sailboat repair keel

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Keel Bolt Inspection and Repair

Ensuring a snug-fitting seal between the keel and hull is essential.

If your potential dream boat has more than 20 years behind her, one item that will likely come up on a survey is keel bolts — the heavy duty fasteners that keep your keel from going on a bottom tour while you reach for handholds on your suddenly tippy craft. And even if you are not in the market for a new boat, it is always a good idea to take a close look at these essential structural components. A proper inspection will require the boat to be out of the water.

Despite advances in imaging technology, keel bolts are still very difficult to fully inspect without a bit of surgery. (We will be looking at keel-bolt imaging options in a future report.) Fortunately, some hints of trouble are obvious, like large gaps in the keel-stub joint, weeping rust stains near the keel-stub joint or crumbling bolt-ends in the bilge.

Keel Bolt Inspection

This year new World Sailing rules requiring a keel inspection took effect. Additional rules related to keels take effect next year. The rules describe the type of inspection required to participate in one of the offshore racing categories.

I’ve included an excerpt from the relevant rules below. The “Mo” preceding each designated subchapter of the rules indicate the category of race, with the lower number indicating the more strenuous race. For example a Category 4 rules apply to boats participating in “short races, close to shore in relatively warm or protected waters normally held in daylight.” Category 0 rules apply to “trans-oceanic races … where boats must be completely self-sufficient for very extended periods of time, capable of withstanding heavy storms and prepared to meet serious emergencies without the expectation of outside assistance.” There are separate categories for monohulls and multihulls.

It is worth noting that none of the new rules apply to Category 4 boats, those participating in near-shore events. Nevertheless it is a good idea to carry out an inspection of keel bolts at each haulout or after a grounding.

World Sailing Rules

Mo3 3.02.2 Effective 1 January 2023, at a haul-out within two years prior to the event, the owner or his/her representative shall inspect the integrity of the keel and rudder following the recommendations in Appendix L. Mo0,1,2,3 3.02.4 Effective 1 January 2022: Inspection after Grounding – an appropriately qualified person shall conduct an internal and external inspection after each unintentional grounding

APPENDIX L Model Keel and Rudder Inspection Procedure The model form is not the only means of meeting the needs of OSR 3.02.3 Evidence of Periodic Structural Inspection, Organizing Authorities may develop on-line forms.

Structural Inspection of a boat shall be completed by a qualified person both internally (may be in the water) and externally (out of the water). The purpose of this inspection is to identify and report to the Owner the condition of the keel and keel structure observed during this inspection. It is the responsibility of the Owner to undertake any repairs.

Consult the Owners’ Manual for the specific boat, steering system and type of keel (e.g. fin, lifting, swinging, full length). Inspect in detail any high-load areas: keel attachment, keel floor, steering systems, rudder(s). Pay special attention to prior repairs, especially following groundings.

Internal Inspection

Check backing plates, bolting arrangements, sump area and keel floors for any signs of cracking, weakening, or de-laminated tabbing. Lead or lead alloy keels may require tightening of bolts to ISO standards due to lead creeping. Inspect keel bolt nuts for corrosion. Check bolt holes for “ovaling.” Visually inspect for possible de-bonding of the supporting structure.

External Inspection

Check there are no signs of stress cracks (not gelcoat cracks) around the keel attachments to hull, or movement or opening around the keel/hull interface which may allow water ingress and consequent keel bolt crevice corrosion. If in doubt, sand back bottom paint/gel coat to identify depth of crack. Check keel tip deflection to insure immediate return and no internal concomitant movement in the keel floor. Visually check high stress regions, particularly around the forward and aft hull attachment areas of the keel, for signs of paint or gelcoat cracking or large, deep blisters, which can indicate separation and structural weakness.

Rudder/Steering system

Check bearing area for any damage/stress cracks; check rudder shaft and blade integrity, especially at any shaft joins and at upper connections to hull/deck. Undertake a tip deflection test to identify any excessive movement. If applicable, check rudder straps and gudgeons for corrosion or cracking.

Lifting and swing keels

In addition to above, check there are no significant stress cracks in structure around pins supporting the keel. Check for extensive corrosion on pins, cylinders and supporting metal structure.

Keel Bolt Repairs

The new rules prompted me to plumb the archives of our files on keel bolt repair, and I came up with several articles going back to some of our earliest issues. (This is one of those fundamental repair jobs that hasn’t change much over the centuries.) Most of the articles were responses to inquiries to PS Advisor , our question and answer section at the back of the magazine.

For some of our more recent articles associated with keel bolts check out: Sistering Keel Bolts ; When Keel and Stub Part Ways ; and Bilge Oil and Keel Worries . There is also an interesting article from our archives in keel bolt inspection . (I’m still looking for Part II to this article which first appeared sometime before 1998.) If you search the website using the term “ keel bolts ” (include quotations to narrow the search) you’ll find additional reports on the shocking keel failures that prompted the new World Sailing rules.

Repairing the Keel Bolt “Smile”

A typical problem that many owners face is the ever-widening gap between the keel and stub, often referred to as a smile, since it usually appears at the bow of the boat and assumes the sardonic curve of a slack tightrope. The course of action described below is the “keel repair light” for a minor separations. If the separation persists or there is significant corrosion or damage that is interfering with a good seal at the keel-hull joint, a more complete and lasting repair is recommended in When Keel and Stub Part Ways . Keel bolt repair is one of those mentally stimulating jobs, because no repair is ever the same, and a proper fix often require a bit of creative engineering. Mars Metal, the maker of most lead keels in North America offers a complete description of keel maintenance  on its website.

Keel bolt replacement is also an interesting project because you find yourself wielding some unlikely tools, like the pickaxe I used to dig a trench under the iron keel of my former boat a 1937 Atkin ketch. The holes were required to punch out the keel bolts from above. Amazingly, all but two of the pre-World War II keel bolts were in serviceable shape. They don’t make them like they used to I suppose.

The following query from a reader is typical of questions we get on this topic.

Our 37-foot boat has a bolted-on keel, and the joint between the keel and the hull keeps breaking open. Should I drop the keel and put bedding compound between the two, or should I try to fiberglass over the joint? The keelbolts are tight.

We’d not recommend simply fiberglassing over the joint. Without resolving the root cause, movement in the keel will likely crack the laminate and all your repair work will be for naught.

There are several possible causes of this problem, including cast-in bolts that are slowly pulling out of the keel, or inadequate structural support for the keel in the bottom of the hull. If you tighten the bolts every year, and more thread shows above the nuts inside the hull, the bolts are almost certainly pulling out of the keel, and you have a big job ahead of you, which would include cutting holes through the ballast near the top, drilling through vertically from the inside of the hull into the openings in the keel, and installing new bolts with nuts and big washers at both the top and the bottom.

We’d also look for signs of compression of the hull laminate in the bilge under the keelbolt nuts. If it’s a cored hull without solid glass up the middle of the hull, the core could be crushing under the nuts, allowing the keel to drop slightly more every year. We’d be tempted to back off the nuts in the bilge, and jack the boat up slightly off the keel. If the joint has indeed opened all the way through, you may be able to lift the hull using a series of screw jack hull poppets, but you must use a minimum of six, and place them only under strongly reinforced sections of the hull, such as under bulkheads.

The boat should be totally emptied of gear, and the tanks should be pumped out to reduce the weight as much as possible. This is potentially a very dangerous job. You must stop immediately if the keel starts to lift off the ground, if the hull begins to dimple under the poppets, or if the chain between the poppets becomes heavily loaded. Sometimes, you can separate the keel by driving a series of hardwood wedges into the joint as you jack up the hull. It’s far safer to do this job with a Travelift or crane, and if you do it in the off-season, the cost should not be excessive.

With the keel free of the hull-but dropped no more than an inch or so, with the bolts still in their holes-thoroughly clean out the joint with a scraper or putty knife, finishing off by flushing thoroughly with fresh water. Allow both the top of the keel and the bottom of the hull to dry. Don’t stick your hand in the joint, ever! We’d put a thick washer of polysulfide compound around each bolt where it enters the hull. but we’d fill the rest of the joint with a stiff, reinforced epoxy putty mixed from resin and Gougeon Brothers 404 high-strength high-density filler.

The boat should immediately be lowered back down on the keel, the keelbolt nuts set up firmly, and the excess squeezed-out putty cleaned away. While you’re at it, replace the existing washers under the nuts in the bilge with large plate washers cut from stainless steel stock at least -inch thick. For a 1-inch diameter bolt, make these plate washers about 4-inch square, and bed them in polysulfide, too. Give the compound a couple of days to cure fully, then re-torque the nuts using a 3/4-inch drive socket and a breaker bar, with a 2-foot length of steel pipe slipped over the breaker bar to increase your leverage. Most manufacturers will provide torque values for the keel bolts, otherwise J/boats offer a guide to torque values based on bolt diameter that can be used.

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Keel maintenance and repair – Part 1

by Simon Jollands | Boat Maintenance , Preparation , Yacht ownership

The job of a sailing boat’s keel is to control sideways movement through the water and to provide a counterweight to the sideways force of the wind on the sails, which causes a boat to heel over.

Keels are designed to act as underwater foils that generate lift as the boat moves through the water, counteracting the leeward force of the wind and enabling the boat to sail closer to the wind.

The most common type of keel used for sailing yachts is the bolted-on fin keel. Fin keels are usually made of cast iron, bolted through the undersides of GRP hulls with substantial stainless steel bolts. Other types of keel include bilge keels, shoal keels, encapsulated keels, lifting keels and canting keels, as used on racing yachts.

While iron is the most common type of ballast, lead is also widely used. Cement or concrete is sometimes used in combination with scrap iron as ballast for wooden and steel boats, but this can lead to steel rusting from the inside and is not considered good practice. Some modern racing yachts have water ballast which can be pumped into tanks to help counterbalance heeling.

Clearly, motor boats do not require deep keels to counterbalance the heeling effect and sideways force of a boat under sail, but nonetheless they do have keels designed to keep them stable and provide structural integrity. Displacement hulls are often ballasted to increase stability. As a result they have a low centre of gravity making them less susceptible to the wind and waves than planing hulls, which are designed for speed and performance.

Keel problems

It is very rare for a keel to fall off a boat. When this happens the incident often receives a lot of press attention as the subject is understandably of concern to boat owners, builders and designers. Marine accident investigators are usually called in and reports are published explaining the probable causes of these accidents.

There are more common incidents involving keels that require inspections and repairs to be carried out.

Keel bolts inspection

Keel bolts should be inspected once a year for signs of corrosion. Most keel bolts of modern boats with cast iron keels are studs, threaded into a tapped hole in the keel. Keel bolts can be made from either stainless steel or galvanised steel.

Lead keels often have J shaped bronze bolts cast into the lead. Bronze is only used with lead keels as bronze and cast iron create a galvanic reaction.

An inspection entails looking from the inside and outside of the boat:

Outside check

• If there is rust appearing along the hull to keel joint then this is a clear warning sign that the studs may be corroding.
• Look for any signs of movement between the hull and keel, such as splits in the seal or cracks in the hull area around the joint.

Inside check

• Do a visual check of the fastenings in the bilges, making sure you take a look at all of them even if they are hard to access.
• Dry and clean the bilge – the bilges should be kept dry at all times to help prevent corrosion of the fastenings, even if they are stainless steel.
• Some staining and minor rust is quite common but heavier corrosion needs to be checked over carefully.
• Surveyors tap the studs with a hammer and know what sounds to listen for. A ringing sound is good, a dull sound is not good.
• Check for any stress cracks in the bilge area around the keel bolts, which indicate there has been movement. If you see damage like this then it would be wise to have the keel removed for further inspection.

Keel bolt corrosion

Keel bolts can sometimes be withdrawn for inspection to check their condition and for any signs of corrosion. This entails first removing the nuts one by one and inspecting the threads for signs of crevice corrosion.

Quite often, it is the middle part (the waist) of a bolt where the corrosion is taking place, which is where the hull joins the keel. This is caused by the failure of the seal at the hull-to-keel joint, which allows sea water to reach the bolts and corrode them. Under these circumstances, the seal will need to be replaced as well as any corroded keel bolts.

If you have any cause for concern it is wise to ask an expert to take a look and advise whether the keel needs to be removed for further investigation and repair.

Keel bolt and hull-to-keel seal replacement

A typical repair involving keel bolt replacement and new hull-to-keel joint proceeds as follows:

• A frame is prepared to support the keel when it is separated from the hull.
• The boat is supported in the boatyard hoist or crane.
• The keel bolt nuts and washers are removed from inside.
• The boat is hoisted a little off the cradle.
• As separation begins steel blades are inserted into the hull-to-keel joint crack to cut through the seal. Steel wedges may be hammered into the joint to encourage separation. This can take several minutes as seals are sometimes reluctant to give way.
• Once the hull and keel are separated the boat is lifted clear from the keel. The keel now rests in the wooden frame.
• The keel bolt studs are inspected. If any are badly corroded or distorted then they are removed and replaced.
• The old sealant is ground away from the flat surfaces of the hull join and keel top.
• The fibreglass hull around the join area is checked for stress cracks. If these are found then the hull will need to be strengthened with new layers of woven fibreglass mat and epoxy.
• The hull and keel top are prepared thoroughly for priming in order that the new sealant can be applied.
• The boat is slowly lowered back down onto the keel, then the backing plates, washers and nuts are fastened. Excess squeezed out sealant is wiped off.
• The nuts will need to be torque tightened according to the recommended keel bolt diameter torque settings as the seal beds down and checked again after the boat is relaunched for any signs of leakage.

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Keel Repair

Keel repair comes in various forms, from leading-edge chips and dings, to keel and hull joint cracking and weak sumps. Structurally improving a weak keel is a necessary safety repair. The Off The Hook Yacht Services paint and fiberglass crew can repair your damaged keel to a surveyor or engineer’s standard using quality materials.

Explore all that Off The Hook Yacht Services has to offer in paint and fiberglass including bottom paint, running gear paint, collision damage, moisture damage, grounding damage, rudder repair, bow and stern thruster installation, hull paint, deck paint, superstructure paint, keel repair, gel coat repairs, hatch and portlight installation, fiberglass wood replacement and custom fabrication. Full boatyard services including haul out & mobile service, engines & systems, electronics, and hardware & rigging are available at the Downtown Wilmington, North Carolina, Cape Fear riverfront location. Off The Hook Yacht Services is a five-minute drive from Wilmington International Airport ( ILM ) and Private FBO; reaching your boat from across the world is steps away.

Repairing Fiberglass On Boats (Complete Beginner’s Guide)

Fiberglass boats are arguably the best kind of boats you can own.  They’re lightweight, fun to use, and easy to maintain.

They’re even easy to repair, and in this post on repairing fiberglass boats, we’ll tell you exactly how to do just that.

Let’s get started!

Table of Contents

Fiberglass Basics You Should Know

Fiberglass is a wonderful material that can be used to repair all sorts of things.

Learn how to work with fiberglass, and you can repair boats, vehicles, bathtubs, and many other items.

You can even learn to create your own parts, canoes, and even coolers.  An entire lifetime could be spent learning how to build and repair things using fiberglass.

But first, you need to know how fiberglass works as well as what it is.  Fiberglass by itself is just a sheet of glass fibers woven or matted together.  By itself, it is not hard, waterproof, or useful for anything.

However, once you apply a chemical resin to the fiberglass, it becomes waterproof, hard, and incredibly durable.  It also remains lightweight, which makes it great for applications such as aircraft, automobiles, and boating.

The type of resin you use, the type of fiberglass you use, and the core material you use will determine just how hard and durable the constructed fiberglass becomes.

Types of Fiberglass Cloth

There are many different types of fiberglass cloths out on the market today.

Some of these cloths include chopped strand mat, biaxial mat cloth, woven roving cloth, continuous roving cloth, carbon fiber cloths, and the list goes on and on.

This being said, there are two types of fiberglass cloths that you’ll be working with:

• Fiberglass fabrics, or cloths
• Fiberglass mat.

The fiberglass fabrics will be your main structural material, but you may end up using a fiberglass mat to help you work around turns and to help waterproof low-stress areas like the live wells.

With these fabrics, you’ll also have different weights.

These weights will help determine how thick and strong the material is.  Popular boating fabric weights are 10 ounces, 6 ounces, 4 ounces, and 1.5-ounce cloths.  These fabrics are sold by the yard and generally come in widths between three and five feet.

The type of fiberglass fabric you choose will be determined by the application you’re using it for.

Also, lighter cloths can be applied in multiple layers, so if you need more reinforcement, you can always combine a 4-ounce cloth and a 6-ounce cloth in two different layers to provide the thickness and strength of a similar 10-ounce cloth.

Types of Resin

There are a lot of different resins out on the market these days, but the two you’ll most likely be working with are either epoxy resin or polyester resin.  Epoxy resin is more expensive than polyester resin, but it is often considered stronger.  It is also more versatile as the epoxy resin will bond well over polyester resin, but polyester resin may not work well over an epoxy.

This being said, different epoxy materials will work better with different core materials.

For example, the polyester resin will melt some foams and plastics.  I found this out the hard way when I mixed some epoxy resin up in a plastic cup.  The resin started leaking right through the bottom of the cup, and I was very thankful that I had decided to play with the fiberglass outside.

Some other types of resin you might run into are polyurethane resin and silicone resin.  These resins are even more expensive than epoxy resin, and it doesn’t really make sense to use them for boat repairs anyway.

Core Materials

The core material is just the material that is encapsulated by the fiberglass cloth and resin.  Core material on boats is usually balsam wood or a foam core.  However, almost any material can become a core material.

For example, I’ve applied several different types of fabric with polyester resin over the top of pieces of cardboard.  The fiberglass and resin are so strong that it turns the cardboard into a hard shell that you can use to make many different things, including small boats.

If you ever need to do a small one-off project that does not require structural support, think about using cardboard as a cheap and easy alternative to creating a mold or using traditional core material.

This being said, your best bet is to use a core material that is meant for your particular application.  For obvious reasons, being out on the water in a damaged balsa wood and fiberglass boat is a whole lot safer than being out there in a damaged cardboard boat.

Also, keep in mind that you don’t always need a core material.  Sometimes you can create a mold that simply holds the fiberglass and resin together until they dry and become components themselves.  Many fiberglass hulls are built using molds that consist of a thick layer of fiberglass and resin, and they are designed to be very strong with many layers of built-up woven fabrics and mats with no core material.

Camper shells are also built this way without any core material.  If you’re curious about what this looks like, just do a quick search for fiberglass campers on this website, and you’ll see plenty of examples.

When you’re doing repairs on an existing fiberglass boat, you may not be using any core material either.

This is especially true if you’re just repairing a crack or hole in a non-load-bearing area.  In this case, you’ll just be applying cloth over the crack and sealing it with resin.

How Is The Fiberglass Applied?

There are a few different ways that fiberglass can be applied.

• Roll it on with a paint roller
• Paint it on with a brush
• Spray it on with a spray gun.

When doing fiberglass boat repairs, you’ll most likely be painting or rolling it on in small batches. 

The way you’ll do this is you’ll mix up a small amount of resin that you can successfully paint on over the fiberglass within about 15 to 20 minutes.  This is about how much time you’ll have before the resin begins to dry and harden.  If you mix too much resin, you’ll end up wasting it, so it’s important to start small until you get a feel for working with it.

Also, keep in mind that all of your fiberglass should be laid out over the area you’re repairing before you begin mixing your resin.

Once your resin becomes active, you won’t have time to go back and cut out pieces of fiberglass.

General Tips for Working with Fiberglass

As we alluded to earlier, fiberglass must be mixed before it can become active.  This is usually done with a hardener.  The manufacturer will tell you just how much hardener needs to be added to the resin.

Gel coats can also be added to the resin, but this shouldn’t be done until you are on your final layer.

If you apply the gel coat too early, you’ll end up having to sand the layer down before you can add any additional layers.

Also, keep in mind that fiberglass resins are meant to be used at different ambient temperatures.  If the temperatures are too high or too cold, the resin will not cure properly.

You’ll know the resin didn’t cure correctly if the fiberglass feels tacky afterward.

Safety Tips for Working with Fiberglass

Fiberglass resins and hardeners can be toxic, and it’s important to keep them off of your body and out of your lungs.

Personally, I only work with fiberglass outside, but any well-ventilated area will do.

Also, if you’re working with polyester resin, you’ll want to wear a respirator.  Not only is polyester resin toxic to breathe, but it smells awful.  The smell is so bad that I won’t even leave the closed bottle of polyester resin inside my house for fear that it will make the house smell bad.

You don’t want to get resin on your skin or your eyes either.  Wear protective clothing, gloves, and safety glasses to prevent this from happening.

For additional protection, you can also get a lotion that will work to coat your hands.  This way, if the resin gets through your gloves, you’ll have an extra layer of protection between the resin and your skin.  If the resin does end up getting on your skin, be sure to wash it off immediately. 

People have been known to develop allergies to epoxy resin, and once you get this allergy, you’ll never be able to be around epoxy resin again.

Fiberglass Buying Tips

• Always buy fiberglass by the roll. Unfortunately, many people will try to sell you folded pieces of fiberglass because it is cheaper and easier to pack, ship, and store it this way.  Sadly, folding fiberglass cloth can weaken the strands, so when you buy fiberglass that is folded, you’re buying cloth that is already damaged.
• Buy the hardener with the resin. It’s always easier just to buy the hardener and gel coats with the resin.  Different resins will need different amounts of hardener, and the manufacturer will usually sell the two as a kit.
• Get good mixing cups. A poorly mixed resin will not work properly.  Get good mixing cups so that you can accurately mix the resin and get the most benefit from it.
• Buy it locally (at first). A local marine store owner can often offer you valuable tips for working with fiberglass, and they can help tell you where you went wrong when you run into trouble.  You’ll probably end up paying a bit more for your resin, but you’ll often end up with some good and free advice.
• Buy the right fiberglass for the job. When you go to buy fiberglass, you’ll notice right away that chop strand mat is dramatically cheaper than all of the other types of fiberglass.  There is a reason for this.  Fiberglass mat is not very strong, and it can be difficult to work with.  Only use fiberglass mat when the job specifically calls for it.  Resins are expensive, so there isn’t any point applying them over inferior fiberglass cloths.

Repairing The Hull

Before you decide to repair your own boat hull, you may want to do a reality check.

Is the boat hull severely damaged?  Is your boat an ocean vessel that is going to be put under a lot of stress?

If you answered yes to these questions, you might want to save this project until you have a lot more experience with fiberglass repair.  In this situation, a bad repair job could put your life in jeopardy, so the money you save will never be worth it.

This being said, there are a lot of small hull repairs that you could tackle yourself without much risk.  For example, a small hole in a small boat that you only take out on the lake shouldn’t be too much for you to handle.  Small cracks or holes in the areas above the water line might not be a big deal either, but please use your best judgment.

Repairing Holes in The Hull

To repair a hole in the hull, you may need to get some new core material.  Try to match the new core material with the existing core material.  Make sure the remaining core material is dry.

Once you have the core material, you’ll need to fit it into the hole.  Next, measure and cut your fiberglass cloth.  Lay the fiberglass over the area, using fiberglass tape if you have to.  Once everything is in place, mix up your resin and apply it over the damaged area.  You may need to do multiple layers.

For professional repairs of ocean-going hulls, the surrounding fiberglass is ground back on a slope of 1:12 to make a large area to be repaired; a 1/2″ thick fiberglass structure would be ground back 6″ in every direction from the hole.

The patch is then built-up with increasingly larger pieces of fiberglass mat and resin.  Again, you need experience before trying this.

Your final coat should be a gel coat that matches the color of your boat.

Alternatively, you could repaint the boat after the repairs have been made.

Repairing Cracks

Be careful when repairing cracks in your hull, as they could be a sign of bigger structural issues.

For example, a balsa boat with cracks in it could have rotten wood inside the hull.

However, if you just see some cracks from when you accidentally backed into a tree last week, feel free to try to take on the repairs yourself.  You probably won’t need any new core material, but you will need some fiberglass and some resin to patch up the crack.

Measure, cut, and layup your fiberglass before mixing your resin, and you shouldn’t have any trouble with the repair.

One thought to keep in mind with a repair like this is that you’ll probably spend more time sanding and painting than you will be doing the actual repairs.  The more time you spend sanding, the better the boat will look when you’re done.

Repairing The Floor and Deck

The first thing you should do before making any repairs to the deck or the floors is to check to see how severe the damage is.

Often-times, decks and floors are made from wood, and if they are spongy or have holes in them, the wood is probably rotten underneath.

Before making any repairs to the fiberglass, you’ll need to take out this rotten wood and replace it.  What seems like a small repair, in the beginning, can often end up being an extensive repair.  If you don’t believe me, just look at all the free “project boats” listed on Craigslist.

Oftentimes you’ll see that the person giving it away received the boat for free himself, thinking that he could do the repairs and get a free boat.

Once he started to tear the boat apart, he realized just how much work and money would be needed and decided to give up on it.

Once you do know what you’re in for, start replacing the decking and flooring, making sure to keep the materials dry until they are encapsulated with new fiberglass and resin.  Also, be sure to make a note of where the different pieces of hardware are connected to the deck, as you’ll need to put them back on when your repairs are complete.

If you’re careful, you can use the old decking that you pull off the boat as a template for creating your new decking.

Once your new flooring is complete, secure it to the boat and begin placing the fiberglass cloth over it.  Be sure to use a good amount of fiberglass as the decking will need to be strong enough to support people walking over it.  Mix up your resin and apply it in small batches.

If you have a large area to do, you’ll be tempted to make larger batches but don’t do this as you’ll only end up rushing the job or finding the resin sets up prematurely.

Flooring Alternatives

Another thought to keep in mind is that you don’t always need to replace your wood flooring with wood.  Some people will skip the fiberglass altogether and simply install an aluminum floor instead.

This can be useful in certain applications but not very useful in others, so you’ll need to analyze your particular situation before you decide to make any changes.

If you do decide to skip the fiberglass, just be careful to find out what changes this will have on the weight of your boat.  Making a heavier boat could reduce your boat’s max capacity and affect the way your boat sits in the water.

Repairing The Keel

The keel is an integral part of a boat.  On a sailboat, the keel keeps the boat upright in the water and helps to keep it stable in heavy winds.

Being at the bottom of the boat leaves it much more vulnerable to scraping the ground and running into rocks.  For this reason, a keel can often take damage even when the rest of the boat remains trouble-free.

The question is, do you want to repair this damage to the keel yourself?  

If you have a small recreational boat that you can easily bring up on land, I’d say go for it.  You can flip the boat over in your backyard and spend as much time as you need applying a new resin and gel coat to the keel.

For boats that you know will be scraping the bottom again, you may want to apply a keel guard as well.  This will help protect your keel, so you don’t have to constantly make repairs each season.

Repairing The Transom

A solid transom will ensure that your boat’s engine doesn’t fall into the water.  If you’re going to make this repair yourself, make sure you’re prepared to do it properly.

Oftentimes the core of the transom needs to be replaced, and you’ll want to make sure you replace it with a material that is as strong or even stronger than the original.  This is especially true if you’ve upgraded the original boat engine to something bigger and heavier.

Once you’ve replaced the core material, the steps for making the repair remain the same.

Apply your fiberglass boat cloth and use as many coats of resin as you need to get the job done.

This repair includes a lot of hard edges, so you may need to overlap your layers of fiberglass at the top to get a good seal.  Take your time and make sure the fiberglass wraps properly, or you’ll end up having to do a lot of sanding at the end of the job.  Also, be careful to account for where the engine will be mounted so that you can match the hardware appropriately.

Repairing Hatches

Hatches are easy repairs, and they’re great for getting started with fiberglass.

When replacing a hatch, use the existing hatch to make a template for the new one.

The new hatch should be easy to make, and you won’t have to use a lot of thick fiberglass cloth since it won’t be the main structure of the boat.

The main thing to keep in mind when doing this repair is that the hatch will need to be sealed properly afterward.  Oftentimes, people will do a great job repairing or replacing the fiberglass hatch, but they won’t seal it properly afterward, and they end with a leaky hatch.

Repairing Scratches

Scratches in the fiberglass usually don’t require extensive repairs, and the cost is usually minimal.

The reason for this is that the fiberglass does not need to be replaced, and the core material is not yet affected.

Unfortunately, some deep scratches in the gel coat can end up creating a lot of prep work.  You’ll end up needing to do a lot of sanding to get the boat to look new again.

You’ll also need to do a good job matching the color.

If your boat is new, this may not be a problem, but if your boat has been out in the sun for a while, you won’t be able to use the original boat color as it will end up being too dark.

You’ll have to color match the boat, or you’ll have to resign yourself to painting the entire boat over again.

DIY Costs vs. Professional Costs

Doing repairs yourself will usually save you money, and they can sometimes even save you on time.

However, some jobs are too big to be done by beginners, and some jobs just take too much time for the DIY repair to be worth it.

I’ll try to give you a breakdown of some of the costs here so you can decide for yourself whether or not the repair is worth paying for or doing yourself.

Example costs from FiberGlassSite.com:

• 6-ounce fiberglass cloth 50” wide and 5 yards long. – $25.00
• 1 gallon of polyester resin with hardener.  – $39.00

With this much cloth and resin, you could do a lot of small repairs of cracks and holes.

A simple hole or crack repair might cost you $50.00 each, so you’d definitely save money on smaller repairs, and you may even have some extra fiberglass left over for the future.

For a balsa core deck repair, you might want ¾ inch core.  This costs about $50.00 for a 2’x4’ piece.  You’ll also need a 10-ounce fiberglass cloth and polyester resin.

This repair might end up costing you a couple of hundred dollars, but it could save you a thousand.

Foam core used for repairing heavy damage to the hull of a sea-going vessel will need to be very strong.  Not only this, but you’ll need to consult with a marine technician to determine what the best combination of foam, resin, and fiberglass should look like.

Between material costs and consulting costs, you’ll end up spending thousands of dollars.  You’ll also end up spending a lot of time, and you may devalue the worth of the boat since a buyer might not feel safe buying a boat that was repaired by an amateur.

In this case, you may be better off paying a professional boat repair company to do your repairs.

Final Thoughts

Working with fiberglass can be tricky, but it can also be a lot of fun.

Learn how to work with fiberglass, and you’ll find an almost endless number of projects to take on.

Just keep in mind that working with fiberglass is not cheap or easy to get into.  If you decide to take on fiberglass projects, be prepared to spend some time and money doing so.

Also, be prepared to mess up a few projects while you’re learning.

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Cast Iron Keel Repair

• Thread starter docschreiber
• Start date Jun 9, 2015
• Forums for All Owners
• Ask All Sailors

docschreiber

I have a '72 Coronado 23-2 that I recently purchased. My intention was to buy a "ready-to-sail" boat, but due to various circumstances that did not happen. I am a complete newbie to sailing and boat repair. The keel (Iron, I think....) had multiple areas of rust showing, so I stripped it down to metal with an angle grinder and 80 grit sanding pad. On the starboard side I have found a large area (1 foot wide by 10 inches tall by ~5-7mm deep) area that someone had filled with Bondo and painted over. I have cleaned it out, and am searching for the best way to fix it right. Any help is greatly appreciated! I've tried uploading pictures here, but keep getting upload errors on the photos. I've reviewed the guidelines and the pics should load, so if anyone can help here I'll get photos up. I put them on my facebook page and made them public, so anyone can view them there. Sorry for the extra step. https://www.facebook.com/chris.schreiber.182  

My last boat had a cast iron keel in similar condition. As I recall, I stripped it to bare metal, treated it with a product called "ospho" sealed it with epoxie, faired it with epoxie with thickener (don't remember what I thickened it with) put on a couple of more coats of epoxie and bottom paint. Still looked good when I sold the years later. Good luck and welcome to the wonderful world of sailing.  

Phil Herring

Sorry about that, the photos were my fault. I was changing some server settings and caused the problem. Should be working now.  

did those settings have anything to do with the gear adds.....when i click on something for sale i get a blank page and have been for 2 days now  

Quite a project to start with! Wow! Starting with a cast iron keel, you've tackled a big one right away, but you're on the right track! Hopefully, you'll get input from a couple of others who've done the same job. One important item in the restoration process is to make sure that you seal it (the 'ospho' step?) right away when you get to bare metal. Don't let it set for a long time between reaching bare/clean metal and sealing it. Especially with the humidity in TN. I let the folks in the boatyard tackle my cast iron keel (pretty much a necessity with our rules on collection and disposal of materials), and I was glad that I did! They had to use a needle gun to remove the old paint and rust, then barrier coated with two coats of epoxy and then bottom paint.  

You can fill and fair that keel with West System 610 thickened epoxy; however, that is expensive. You can make your own with West System epoxy resin, slow hardener, and West 404 High Density Filler. The 404 is for underwater use. Mix the resin and filler, adding filler til you have a thick paste, a little thicker than you want. Then add the right amount of harder and mix that in. Then fill and fair the damage / voids in the keel. Mix it in a wide Tupperware container to make it easier to mix and to keep it from kicking. I would use a thinner mix on the rest of the keel to make it easier to spread and get an even coat. Use the West System pumps to get an exact ratio. After the epoxy residue hardens in the pan, just flex the pan a little to break it out. Thanks, Andrew  

Cast iron can be welded as well. Maybe one of our welders will come on and explain the process as I am at least aware that it is a precise concept to get it right. Preheat the cast iron? Chief  

actually chief it can be welded ......but it is a bear to do..... yes preheating is one thing that has to be done and after welding it ...it may have to be cooled down slow and controlled as in cooling it down in temp drops ...most of them are made of very low grade materials or have a lot of surface rust scale in some cases it may be better to have a new one made from a casting company...there are a lot variables in this process...but from his description i would not worry about welding it just fill it with a good grade epoxy filler and fair it out and go on  

Woody: I figured you might address the welding prospect. Thanks for giving us more detail on that. Chief  

Agprice and Sprega called it, Strip to bare metal Treat surface Barrier coat Epoxy fill Barrier coat Paint Welding would be a disaster even if you could figure out a way to do it. You want SMOOTH surface. The Ospor step chemically changes any surface rust to an inert substance, ready to be barrier coated. So no rush.  

Jackdaw said: Agprice and Sprega called it, Strip to bare metal Treat surface Barrier coat Epoxy fill Barrier coat Paint Welding would be a disaster even if you could figure out a way to do it. You want SMOOTH surface. The Ospor step chemically changes any surface rust to an inert substance, ready to be barrier coated. So no rush. Click to expand

I wasn't suggesting welding. I was just curious as to viability and sailing safety and if welding would be better in this case. I got the answer from you two and that was my objective; for clarification for all of us. Thanks, Chief  

I pulled the keel and ground the rust off. I the wire wheeled it. The next step or actually three steps was the POR15 process. Degrease and then etch with the recommended products. Got everything from Eastwood. I then top coated the whole thing with Rustoleum industrial gray. Worked mint. Second time BTW. First time was all the prep work and a rust converter before Rustoleum primer and paint. POR is bulletproof. Touch up where you hit rocks. Yes the Ocean is shallow. Who knew!! Happy Sailing!! Ken B CMDRE North East Trailer Sailors  

Jackdaw is right about the ospho. Also, I have had EXCELLENT results with epoxie from US Composites. Way cheaper than west.  

Sprega said: Jackdaw is right about the ospho. Also, I have had EXCELLENT results with epoxie from US Composites. Way cheaper than west. Click to expand

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Fiberglass Boat Keel Repair

Has your sailboat or powerboat sustained damage to its vulnerable keel? Impact with underwater objects can crack, chip or puncture a fiberglass boat’s keel, compromising structural integrity.

When keel damage occurs, proper repairs are essential for restoring seaworthiness.

This article provides a DIY overview of assessing damage and performing a fiberglass boat keel repair.

5. Fairing & Refinishing Repairs

Fiberglass boat keel repair guide, 1. inspecting keel damage.

After a grounding or collision, thoroughly inspect the keel for cracks , fractures, holes and delamination. Look for stress cracks radiating from the point of impact. Check inside the boat along the keel joint for signs of damage. Determine how extensive the repairs need to be.

Minor chip repairs may only require some basic grinding, filling and refinishing.

Major cracks, holes and delaminated bottom skin necessitate more extensive fiberglass work.

If damage compromises over 30% of the keel depth, professional repairs may be needed to meet safety standards.

2. Grinding Out Damaged Areas

Start by sanding and grinding down all cracked, chipped and punctured areas with 36-80 grit disks to open up the damage.

Remove loose fibers and degrade the gel coat surface to improve adhesion. Create a rough surface profile for the repair compounds to mechanically bond with.

For cracks, the saw cut a V-groove along the length with a circular saw at least 1/8″ deep to increase the surface area. Grind damaged fibers at the root.

Vacuum and solvent wipe repair areas to remove debris and grease before applying materials.

3. Filling Holes, Cracks and Chips

Fill scratches, gouges , cracks and drill holes with thickened epoxy adhesive filler thickened with colloidal silica or micro balloons. Apply filler in layers until flush with the surface, allowing cure time between applications.

For cracks, wet out the inside surfaces with neat epoxy before applying thickened epoxy. Overfill the repair and allow the adhesive to cure before final sanding.

Finish filling holes and cracks by applying structured repair materials.

4. Applying Fiberglass Repair Laminates

Cut several plies of woven fiberglass cloth to overlap damaged areas by at least 2″ on all sides. Pre-fill any cloth texture with epoxy filler.

Wet out each layer of cloth with epoxy resin before applying it to the repair. Use a plastic spreader to smooth the cloth, removing air pockets and excess resin. Apply 4-6 layers of cloth based on existing laminate thickness.

For cracked keels with bottom skin delamination, the detached skin may need re-bonding and supplementary layers of glass cloth overlap for added structural strength.

Allow resin fill coats to fully cure between layers based on product guidelines.

Once the repair plies fully cured, use 80-120 grit sandpaper to fair in the repair and blend with surrounding fiberglass. Fill any remaining pinholes or surface irregularities with polyester or epoxy filler/fairing compound, then sand flush.

Solvent clean and apply three coats of two-part polyurethane topside paint to match your boat’s color.

Lightly sand between paint coats. Touch up registration numbers, draft marks and antifouling bottom paint as needed.

Final Thoughts

Performing quality fiberglass repairs takes some work, but restored integrity and seamless refinishing is achievable with the right techniques.

Follow safety precautions when grinding glass materials and mixing/applying resins. Use protective equipment and ensure adequate ventilation.

With time, patience and the proper methods and materials, you can repair damage to your boat’s vulnerable keel without breaking the bank.

Take things slow, allow adequate cure times and the result will pay off with a keel that’s shipshape. Your fiberglass sailboat or powerboat will be back cutting smoothly through the seas in no time!

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How To Fix Small Holes In A Fiberglass Boat? 6 Easy Steps

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Keel damage; what would you do; what will it cost? (with pictures)

• Thread starter geneseo1911
• Start date Aug 4, 2011

geneseo1911

Petty officer 2nd class.

• Aug 4, 2011

Fleet Admiral

Re: Keel damage; what would you do; what will it cost? (with pictures) Woodonglass will be around here in a little while and he'll have a lot of good info for you on this subject.  

Woodonglass

Supreme mariner.

Re: Keel damage; what would you do; what will it cost? (with pictures) This kind of repair SHOULD be done from BOTH sides. BUT... If it's solid NOT spongy at all on the interior where the heavy glass is showing and totally dry, then... You could grind it out and feather back, lay some CSM, and 1708 cloth, fill and fair, Gelcoat or paint and be done in a day. The Keel Guard is Optional but NOT a bad idea. Since you've done some glassin, you could do this and it wouldn't be all that bad, even upside down. Not GREAT, but not THAT BAD!!!! If you PAY for it expect at least 2 hundred bucks. If you want a quick fix to finish the season, acetone wash, Marinetex go. But I WOULD fix it with glass eventually if she wer mine.  

Re: Keel damage; what would you do; what will it cost? (with pictures) Woodonglass-you just made my day! I am fully prepared to drop $500 to avoid grinding fiberglass over my head! After reading some of the other keel threads around here, I was afraid you'd say $2000, not $200. Does the old roving have to be ground into, or will the new resin adhere to it so long as it's dry? If it's not leaking, will I be causing substantial damage by splashing it before getting any work done? I was hoping to go Sunday. Here in central IL, marine supplies are hard to come by. I can't get Marinetex locally (let alone FG supplies), so it'd be next week before I could do anything. Thanks again.  

Petty Officer 1st Class

BWT said: I agree to an extent with WOG post; IMHO it needs to be glassed now (and if it were me I would do everything from the exterior of the hull; csm, couple 1708 and finish with a couple more csm all in poly). What I feel a little leery about is doing a quick fix with marine tex or some other putty and calling it good for the Summer (or even the weekend). Granted he is strongly recommending doing a proper repair in the Fall, but personally I would tackle it now and not wait. Since you've done some glassing, this is a 1 day job. Besides, forecast for the weekend doesn't look all that good for you I'd get'er done now and be ready for next week. If you do it yourself, less than $75 in materials. Click to expand...

• Aug 5, 2011

Re: Keel damage; what would you do; what will it cost? (with pictures) Here is what you could do. Get a floor jack and lift the bow of the boat enough to slip 4x4s between the boat and trailer. Then put the trailer jack all the way up. That should get you enough clearance so that you don't have to lay under the boat. Get an angle grinder and in less than 5 minutes you would have enough material removed to start patching. Then do what others suggests with the CSM and 1708. Mix some filler in with the resin and apply a skim coat to smooth things out. Sand it down. Then put on your keel guard.  

Re: Keel damage; what would you do; what will it cost? (with pictures) Welcome to iboats, good to see another old cobalt! Mine is a 78 trihull, similar coloring and same engine! good luck on the repair.  

Re: Keel damage; what would you do; what will it cost? (with pictures) I have several options to lift the boat....forklift, loader tractor, and backhoe, but all leak down with time. How much support would it take to keep from damaging the hull? If the stern stays on the bunks, wouldn't the corners of blocks on the bunks in the front put a lot of pressure on a small area of the hull? Thanks for the welcome jmorgan. I've been lurking for a while and watched your progress with great interest because your boat is so similar to mine. I'm amazed at how well this thing has held up compared to most boats its age. There is something to be said about the way Cobalt builds things. Even the interior is in good shape, although indoor storage is partly to thank for that. I'll post up some more comprehensive pictures once I get all these little jobs done. Today I'm replacing the clock (the only gauge that didn't work), installing my GPS/sonar, and re-installing the teak swim deck.  

Re: Keel damage; what would you do; what will it cost? (with pictures) yikes! I guess that 'glass is stronger than I thought! That certainly makes it seem less insurmountable. At least on the trailer it couldn't fall on me so long as I was careful where I stuck my arms. I still don't think I'd get under the boat in your picture!  

• Aug 7, 2011

Re: Keel damage; what would you do; what will it cost? (with pictures) UGH. Marina wants 1200-1500 to do the fix. What a scam. I guess now I'm looking for somewhere else to go that will be more reasonable. Slim pickings around here, though. Anybody know a good (reasonable) 'glass man in east central illinois?  

Re: Keel damage; what would you do; what will it cost? (with pictures) This is not that hard of a repair to do. Even upsided down. It's gunna be 32" by 8". You'll need a gallon of resin a yard of CSM and a Yard of 1708 Biax. Your total cost should be under $200 bucks and you'll be done in a day. You can precut the layups and wet em out before you lay em so it will be easier to do and not as messy. We'll talk you through everything. You can DO IT!!!!  

• Aug 10, 2011

Re: Keel damage; what would you do; what will it cost? (with pictures) Well, I went down to Mom & Dad's this morning and dug all my fiberglass supplies out. Much to my surprise, not only do I have all the materials I'll need, including gelcoat, my resin is still fresh. I was gonna start on it tonight, but we had a fire call, so I didn't get to. Hopefully tomorrow. I'm planning to lift it by the front ring with the tractor, slide some blocks under it to hold it off the trailer, and let it back down. Then grind off any loose stuff and scuff the good stuff. Then 1 csm, 1 cloth, and 1 more csm. Fair and Gelcoat. I've never done gelcoat before....any tips? I need to get the keelshield ordered. Is it true that sitting on a roller will ruin it in short order? The front most roller contacts the keel, but has little pressure on it. I can turn the roller by hand with the boat strapped down. Should I relocate the roller or not worry about it?  

Senior Chief Petty Officer

• Aug 11, 2011

Re: Keel damage; what would you do; what will it cost? (with pictures) it's good to see your trying it on your own. it's not that bad, just take your time and dont get frustrated. gel coat is forgiving and it can be cleaned up with a little elbow work and some different grit sand paper as you can find out from more experienced pro's on the website. as for the roller position, i think i would try to find out either from your buddy or launching what caused this to happenand where like this? was it the position of the rollers? was it run aground? from the close up pictures, it looks like there is some pretty good scratches and marks around the damaged area. my trailer is all roller style and the weight is distributed as close as possible equally across all the rollers and v-block with the exception of the cross beam "protector" rollers. good luck and keep us posted.  

• Aug 12, 2011

Attachments

Re: Keel damage; what would you do; what will it cost? (with pictures) ok.....hang on here...... read the first 5 pages of my thread..click the link in my sig..it has all you need to know......more in a sec.....  

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Keel delamination

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I think you are looking at an expensive repair to do this right.  

It is hard to tell what is happening from your description, and photos. The first step would be to bring in a marine surveyor to get a definitive determination of the extent of the damage and a proper approach to the repairs. You will need to find a surveyor who has a strong background in engineering structural repairs to get a definitive answer. My best guess from your description is that minimally the trailing edge of the keel encapsulation envelope was driven up through the hull; sheering and probably delaminating the hull at that location. With that type of damage it is also probable that the laminate at the forward end of the keel is also crushed and delaminated. In addition, that kind of damage is usually accompanied by delamination of the encapsulation envelope from the ballast casting. While the potential extent of the damage is largely conjecture at this point, even if the damage literally is only the encapsulation sheering through the hull, this is a very difficult repair to make , and one that would require working from the interior of the boat for a long length and width. Normally this would require grinding a wide deep tapered area (probably several feet either side of the edges of the damaged laminate and most of the depth of the hull thickness) and then building up new fiberglass and epoxy resin to greater than the original hull thickness but tapered at the edges. It also often involves adding transverse and sometimes longitudinal frames to spread the load into undamaged portions of the hull. It is anything but an easy and cheap repair to do properly. If the damage involves delamination of the hull either beyond the visible damage, and/or delamination at the forward end of the keel, and/or delamination of the encapsulation envelope, this is nearly an impossible repair to make properly (i.e achieving the original strength of the boat) and would be prohibitively expensive if done right. Hopefully a qualified surveyor can determine the extent of the damage and method of repair, and hopefully the damage is as minor as possible rather than totaling the boat. Jeff  

Jeff_H said: It is hard to tell what is happening from your description, and photos. The first step would be to bring in a marine surveyor to get a definitive determination of the extent of the damage and a proper approach to the repairs. You will need to find a surveyor who has a strong background in engineering structural repairs to get a definitive answer. My best guess from your description is that minimally the trailing edge of the keel encapsulation envelope was driven up through the hull; sheering and probably delaminating the hull at that location. With that type of damage it is also probable that the laminate at the forward end of the keel is also crushed and delaminated. In addition, that kind of damage is usually accompanied by delamination of the encapsulation envelope from the ballast casting. While the potential extent of the damage is largely conjecture at this point, even if the damage literally is only the encapsulation sheering through the hull, this is a very difficult repair to make , and one that would require working from the interior of the boat for a long length and width. Normally this would require grinding a wide deep tapered area (probably several feet either side of the edges of the damaged laminate and most of the depth of the hull thickness) and then building up new fiberglass and epoxy resin to greater than the original hull thickness but tapered at the edges. It also often involves adding transverse and sometimes longitudinal frames to spread the load into undamaged portions of the hull. It is anything but an easy and cheap repair to do properly. If the damage involves delamination of the hull either beyond the visible damage, and/or delamination at the forward end of the keel, and/or delamination of the encapsulation envelope, this is nearly an impossible repair to make properly (i.e achieving the original strength of the boat) and would be prohibitively expensive if done right. Hopefully a qualified surveyor can determine the extent of the damage and method of repair, and hopefully the damage is as minor as possible rather than totaling the boat. Jeff Click to expand...

I wonder if there will be any recourse to whomever did the initial repair. Did they do it for you, or the former owner? Clearly it was not a structural repair, just cosmetic. This one has some heartbreak coming, I'm afraid.  

The repair was done by the prior owner.  

Go with Jeff on this I just call them stringers. See if there's a way you can add bolts (Keel bolts) to the encapsulated keel, bring them up through the new stringers it's really the only thing that's going to keep that keel from dropping off the boat (in my humble opinion) You may have a case. If the grounding and damage was not disclosed prior to sale but I am not a lawyer.  

is this a bolt on keel?  

No. Read the first post.  

What did your surveyor say about this when you bought it. What does the insurance claim surveyor have to say about the repair ? (you should be able to find out who that was).  

There was no problem with the keel when I bought it and I also reviewed photos and invoices with him.  

No problem that you could see under the bottom paint. if it cracked the added fiberglass plys it was not fixed correctly. if the hull was damaged to the point that it leaked then all the laminations were damaged and putting a patch on the hull is not going to fix it. I am with Jeff it will need an extensive amount of work to fix correctly  

What I find most interesting about this thread (and particularly Jeff's excellent post above) it what it reveals about encapsulated keels. Much has been posted on this site about bolted on keels, and some could get the idea that encapsulated keels would be the way to avoid those keel bolt issues. This shows that you really just trade off some of those issues for others. Each keel type has it pluses and minuses. And hard groundings are bad, regardless of the keel type.  

How large an area would a grounding impact... what area of the hull is delaminated? Obviously it depends on the force of the impact. Aren't the forces distributed over a fairly large area? Unless there is a visible sign... the hull laminate could be delaminated and that is determined by "sounding" it. I am having difficulty in visualizing the forces vectors on an encapsulated keel leading to a local breach aft... other than in a crude way with the encapsulated aft end moving the most and thus the delamination there. Why doesn't is crush where the impact is?  

Am I mistaken, or do some builders (Passport??) still bolt on an iron keel and then encapsulate it to "theoretically" preserve the keel joint and extend the lifetime of the attachment?  

So unless repaired... a delamination can grow and or migrate. Can there be "invisible" delaminations? ie... inside the layup but without telegraphing to anything visible? I suppose this would be something small. Would a small delamination be less concerning?  

Delamination often is invisible occurring solely within the skin, and it does not need to be 'small' in area to remain invisible. There is no way to say definitively whether a small delamination would be less concerning since it depends on where it is: i.e. how that spot was built and how much stress that area actually has, For example, some years ago I walked around a boat yard tapping on encapsulated keels, Roughly half of those had some amount of delamination (over a foot or so in dia.) between the ballast casting and the encapsulation envelope. While that represents a weakening of the boat's strength, it may or may not be consequential. I also looked at a boat with its owner that had a hard grounding. There was perhaps a 6" dia. area at the trailing edge of the keel that sounded like it was delaminated. That potentially would be far more consequential and was addressed before the boat was put back in the water. Jeff  

Wow Jeff, incredible presentation. Thank you. How many surveyors are as knowledgeable?  

Dave_R said: The repair team, the seller and I can't agree on what we're seeing. Is this a normal seam? Or is this a sinister crack through a good chunk of the keel? Your thoughts? Click to expand...

Hard to know from 2 pics. What is the keel made of? How many bolts connect the keel to the hull? The crack on both sides. Keel is ballast. Suppose a chunk was missing or it was made of solid foam.... and bolted on and failed in. What would be the impact? Obviously less ballast. What difference would that make? GUESS If the chunk is lead or cast iron and securely attached to the hull.... I would think it would have no impact of the boat and performance. This assumes that there are adequate bolts for the keel and the broken bit. Hard to imagine the section broke free... but how to explain a section cracking like that and remaining where it belongs? I say if there are enough bolts for both sections... it's no problem. I AM NOT A MARINE ENGINEER OR SURVEYOR .  

looks like the edge of a fillet tape. is it an encapsulated or bolted on keel?  

Overboared, its an encapsulated keel. No keel bolts. If this is a fillet tape, does that mean there is a design seam around the keel? Certainly a possible explanation. The line does not show the evidence of being a repair. In tat case if it is a designed seam, then wouldn't a seam at that location cause a weakness in the structure at a place where there should NOT be a seam? TakeFive, good suggestion. The purchase survey was done before all this grinding was done. The purchase survey noted the crack in the original, "bondo" repair. Grinding that out is how we found the current "seam" or sinister crack. A 2nd opinion is in order. The original surveyor seemed to be well qualified--here's his info. Capt. Christopher Day SAMS, AMS # 1289 ABYC Standards Cert. 100GT Captain Coastline Marine Services of Florida, LLC 772.643.7300 He is also a chapter head of the local chapter, if that adds any weight. However, he did not seem to be an expert on older sailboats.... You don't, by chance, know a qualified surveyor who would know sailboats of this vintage, do you?  

JHaley, thanks for the pictures and detailed explanation. Your 2nd picture, the crack where the keel joins the hull, is that the AFT end fo the keel? If so, that is very similar to the crack on the Gulfstar 44 I'm considering.  

Yes it is aft end of the keel. If the crack opens up when you pick the boats up in straps then there is more going on than a simple seam.  

Wow - what good timing. I also have a Gulfstar 44 with keel issues, though fortunately not due to grounding at least as best as I can tell. The keel is weeping/leaking at the bottom and causing stalactites to grow from whatever dissolved material (lead? concrete?) is leaking out. Presumably this is because it is leaking into the keel cavity from the bilge - the boat is currently on the hard and until recently water had still been leaking in through the hatches. I think we've finally gotten that taken care of and the bilge is now dry so we'd like to address the keel. We've removed the floor and will be removing the tanks so we can try to seal this and possibly fill any voids in the keel. The floor needed to go anyway as it had rotten spots due to the leaking hatches that the previous owner never fixed 😒. Any insight or pictures either of you could give into how the keel is constructed would be very helpful before we begin tearing into it. I'll get some pics of mine this weekend and post them. Actually any info or pics on these boats in general would be appreciated as we've purchased a rather neglected one located inland so we really don't have any marine services or resources locally - there isn't even a travel lift available here - and we're mostly working blind to try to restore her.  

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Gagarin Cup Preview: Atlant vs. Salavat Yulaev

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Gagarin cup (khl) finals:  atlant moscow oblast vs. salavat yulaev ufa.

Much like the Elitserien Finals, we have a bit of an offense vs. defense match-up in this league Final.  While Ufa let their star top line of Alexander Radulov, Patrick Thoresen and Igor Grigorenko loose on the KHL's Western Conference, Mytischi played a more conservative style, relying on veterans such as former NHLers Jan Bulis, Oleg Petrov, and Jaroslav Obsut.  Just reaching the Finals is a testament to Atlant's disciplined style of play, as they had to knock off much more high profile teams from Yaroslavl and St. Petersburg to do so.  But while they did finish 8th in the league in points, they haven't seen the likes of Ufa, who finished 2nd. 

This series will be a challenge for the underdog, because unlike some of the other KHL teams, Ufa's top players are generally younger and in their prime.  Only Proshkin amongst regular blueliners is over 30, with the work being shared by Kirill Koltsov (28), Andrei Kuteikin (26), Miroslav Blatak (28), Maxim Kondratiev (28) and Dmitri Kalinin (30).  Oleg Tverdovsky hasn't played a lot in the playoffs to date.  Up front, while led by a fairly young top line (24-27), Ufa does have a lot of veterans in support roles:  Vyacheslav Kozlov , Viktor Kozlov , Vladimir Antipov, Sergei Zinovyev and Petr Schastlivy are all over 30.  In fact, the names of all their forwards are familiar to international and NHL fans:  Robert Nilsson , Alexander Svitov, Oleg Saprykin and Jakub Klepis round out the group, all former NHL players.

For Atlant, their veteran roster, with only one of their top six D under the age of 30 (and no top forwards under 30, either), this might be their one shot at a championship.  The team has never won either a Russian Superleague title or the Gagarin Cup, and for players like former NHLer Oleg Petrov, this is probably the last shot at the KHL's top prize.  The team got three extra days rest by winning their Conference Final in six games, and they probably needed to use it.  Atlant does have younger regulars on their roster, but they generally only play a few shifts per game, if that. 

The low event style of game for Atlant probably suits them well, but I don't know how they can manage to keep up against Ufa's speed, skill, and depth.  There is no advantage to be seen in goal, with Erik Ersberg and Konstantin Barulin posting almost identical numbers, and even in terms of recent playoff experience Ufa has them beat.  Luckily for Atlant, Ufa isn't that far away from the Moscow region, so travel shouldn't play a major role. 

I'm predicting that Ufa, winners of the last Superleague title back in 2008, will become the second team to win the Gagarin Cup, and will prevail in five games.  They have a seriously well built team that would honestly compete in the NHL.  They represent the potential of the league, while Atlant represents closer to the reality, as a team full of players who played themselves out of the NHL. 

• Atlant @ Ufa, Friday Apr 8 (3:00 PM CET/10:00 PM EST)
• Atlant @ Ufa, Sunday Apr 10 (1:00 PM CET/8:00 AM EST)
• Ufa @ Atlant, Tuesday Apr 12 (5:30 PM CET/12:30 PM EST)
• Ufa @ Atlant, Thursday Apr 14 (5:30 PM CET/12:30 PM EST)

Games 5-7 are as yet unscheduled, but every second day is the KHL standard, so expect Game 5 to be on Saturday, like an early start. 

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University of Notre Dame

College of Engineering

Keeping an even keel: Notre Dame engineers take first place in AI-controlled boat competition

May 21, 2024 May 21, 2024

A team of seven Notre Dame Engineering students clinched the 2024 Overall Grand Champions title and took first place in the Course Challenge at the inaugural Artificial Intelligence Maritime Maneuver Indiana Collegiate Challenge (AIMM ICC).

The event, a collaboration between Trine University and Crane NSWC, took place at Pokagon State Park in Angola, Indiana, April 26-28.

Teams from six Indiana universities used artificial intelligence to pilot a low-profile vessel (LPV). LPVs evade radar detection by staying close to the water’s surface, making them ideal for carrying out law enforcement and security missions requiring stealth and maneuverability.

AIMM team members were aerospace and mechanical engineering majors: juniors Aidan Francfort , Rebecca Gilpatric , and sophomores Steven Vanden Noven , and Felipe Pinho Muller ; and computer science and engineering majors: sophomores Ryan Paillet, Allen Uy, and Manny Hamer .

Teams were given one hour to complete a series of missions, including slaloming between red and green buoys, retrieving an infant-sized mannequin, deploying and communicating with a sensor, and delivering an object to land—a challenge the Notre Dame team met by flying a drone from the LPV.

High winds and rough water on April 27 made conditions less than ideal for the precise maneuvering of a 300-pound, remotely controlled boat, especially one loaded with 1000 pounds of sand—necessary to maintain the boat’s low profile—plus a cargo of delicate electronics.

“The boat rocked like crazy against 30-mph winds,” said Paillet , the team’s project lead. “But it dealt with all the abuse quite handily and powered through the waves, which sometimes splashed over the entire vessel.”

Unlike traditional remote-controlled vehicles, the team’s LPV was capable of navigating autonomously, while retaining the option of manual controls when needed. The team engineered the systems that transferred power and data throughout the boat and also programmed the custom AI vision models to detect buoys, color-coded rings—even people. 

“I think the team succeeded because we made continuous refinements to designs that were simple yet effective,” said Gilpatric . “I feel like all the time we spent on our boat was completely worthwhile, and the team’s small size made it possible for me to make major contributions.”

Next year, the team plans to further develop the LPV and drone’s autonomous capabilities to make them operational even in rough conditions, said the team’s advisor Enes Aydin , Learning Center Manager at Notre Dame’s Engineering Innovation Hub .

— Karla Cruise, Notre Dame Engineering

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