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A couple nearing retirement—weekend cruisers on board smaller boats all their lives—were ready to do some longer cruises. After a few false starts and boats that didn’t live up to their listings, the couple found what they believed was the perfect boat. They set up a survey with a highly recommended surveyor and made plans for the boat to be hauled.

These teak decks are past their prime. The surface has worn away, exposing screw heads and the bottom of the caulking groove. Chances are that water has penetrated the teak and is working its way into the deck core. 

These teak decks are past their prime. The surface has worn away, exposing screw heads and the bottom of the caulking groove. Chances are that water has penetrated the teak and is working its way into the deck core. 

From the dock, everything looked perfect, but as the boat was hauled, the sun glistened on the bottom. They saw blisters. The couple began contemplating whether it was worth it to pursue the boat.

Buying or selling a boat can be exciting, but stressful. The seller wants to present his boat in the best light for a quick sale, while the buyer doesn’t want to get stuck with a bunch of problems. Every boat owner has a different tolerance for making or paying for repairs, and there is a balance to be struck among what the boat costs, what you’ll pay for repairs, and what the boat will be worth afterward.

If a large enough problem arises at survey, what will it take to keep the deal from dying a bloody death? (Disclaimer: No boats were hurt in the making of this article.)

Initial core removal requires careful cutting and grinding. This is early in the process since the top skin has been removed, but the core or deck fills have not. New core will be installed along with a new top skin and a great deal of fairing and painting. 

Initial core removal requires careful cutting and grinding. This is early in the process since the top skin has been removed, but the core or deck fills have not. New core will be installed along with a new top skin and a great deal of fairing and painting. 

Wet Core

Perhaps no finding is more vexing than moisture in the core. Most fiberglass decks and cabin sides, and some hulls, will be composed of a fiberglass skin, a core material and an internal fiberglass skin. If a penetration of either skin occurs and lets rain or seawater into the core, damage can ensue. Builders use a variety of cores such as plywood, end-grain balsa and foam. If plywood or balsa get wet, they can rot and lose their structural integrity. If any of the coring materials contain enough water and freeze, the expanding ice can split the two skins apart, causing even more damage.

A moisture meter in the right surveyor’s hands will determine if there is a difference between a dry area and an area with higher relative moisture, but it won’t necessarily tell you if there is freestanding water inside. The only way to determine this (barring brown water running out) is to remove hardware and inspect the holes, or drill more holes.

Higher moisture readings around one stanchion or cleat probably indicate an isolated problem that doesn’t have to sink the deal. Significant moisture across much of the deck, cabin or hull could mean a structural problem or a condition that affects the boat’s value.

Years of deck leaks have promoted corrosion along the cribbing interface of this tank. Tanks can be well-hidden behind sound deadening and packed into inaccessible locations. Mirrors, cameras, and borescopes should be employed to inspect as much of the tank surface as possible. 

Years of deck leaks have promoted corrosion along the cribbing interface of this tank. Tanks can be well-hidden behind sound deadening and packed into inaccessible locations. Mirrors, cameras, and borescopes should be employed to inspect as much of the tank surface as possible. 

The core material also plays a part in the decision about whether to proceed with the sale. If the core is not too wet or rotten, it likely can be dried out. This is easier to do with foam core. Significantly wet or rotten wood core will likely need replacement. If moisture is in multiple large areas, it can mean so much costly work that it may make sense to pass on the boat altogether.

Teak Decks

An artfully installed teak deck is a glorious sight. The symphony of curves amplified by the lines of black seam compound really takes a yacht to the next level. Plus, teak decks make for a wonderful nonslip surface. The downside is that even as long-lasting as teak is, poor installation, maintenance and time can create the need for an expensive repair.

Most modern teak decks are installed without any fasteners, or with minimal fasteners. The teak is vacuum-bagged or weighted down in epoxy to bond it to the deck without voids. But, some older decks were screwed down; in some cases, a traditional wooden boat deck ruins a perfectly waterproof fiberglass deck after a bunch of holes are drilled into the core. As soon as the seam compound between the teak strips fails, water seeps underneath the teak and into the deck.

A blister repair can involve an enormous amount of crew hours. From peeling off the damaged laminates and bottom paint, to fairing the bottom for new glass, applying the glass, sanding, fairing and applying a barrier coat, it’s a big job. But in skilled hands, the result is better than new. 

A blister repair can involve an enormous amount of crew hours. From peeling off the damaged laminates and bottom paint, to fairing the bottom for new glass, applying the glass, sanding, fairing and applying a barrier coat, it’s a big job. But in skilled hands, the result is better than new. 

Traditionally, teak has been the optimum wood for a boat deck. It’s an oily wood that bleaches to a consistent gray and is hard enough to last a long time. Unfortunately, we’ve overused it, and the natural stocks are dwindling. Plantation teak does exist, but it can be challenging and expensive to find planks of high enough quality and length.

If there is enough wood thickness remaining, and if the deck core underneath is dry, then a failing teak deck’s life can sometimes be prolonged by routing and recaulking the seams, and resetting the fasteners. On a typical 42-foot powerboat, this work might run $25,000.

Purpose-made vacuum pumps and single-use tubing are the start of a clean fluid sample. Filling out the form with accurate and complete information will allow the sampling lab to provide the most useful diagnosis. 

Purpose-made vacuum pumps and single-use tubing are the start of a clean fluid sample. Filling out the form with accurate and complete information will allow the sampling lab to provide the most useful diagnosis. 

Other options for teak removal, repair of the fastener holes, fairing and nonslip paint might run $30,000. Covering the repaired deck with a teak substitute could reach $60,000; complete replacement with like-new teak might top $80,000.

Your surveyor should check existing teak decks for loose bungs, damaged or missing seam compound, and split or loose planks. Check around fittings on the deck for differences in wood thickness. If there is a mound of wood at each deck fill, then you know how much wood has been lost in the deck.

Evidence of a wet deck core, or signs that it’s time to replace the teak, may be cause to look for another boat.

Fuel Tanks

Finding a trickle of fuel under a fuel tank can be disappointing, but should the discovery stop you from buying the boat?

The answer greatly depends on how easy it’s going to be to replace the tank. Sometimes, it’s a nonevent: A recent boat we worked on had a large leaking tank under a large hatch; the tank was cut up and removed through the salon door, and multiple smaller tanks replaced it.

Other boats are not so easy. Tanks outboard of engines, or situated such that the engines need removal, can exponentially raise the cost of replacement. Many boats lack large enough openings to remove an engine, let alone a large fuel tank. A
difficult tank replacement can approach the value of some boats.

Note that aluminum tanks can also corrode from the inside, especially if there is water present in the fuel. This problem will not be visible during the survey unless the tanks are leaking. The presence of fuel under a tank or the bilge should be taken seriously.

When inspecting a prospective boat, make an effort to see the top of the fuel tanks, especially if they are saddle tanks below teak side decks. Deck fills have a habit of leaking. Water trickles down the fill hose and can stand on top of the tank, slowly rusting or corroding the top.

If the boat has iron tanks, look closely for signs of rust or scaling on outside surfaces. Suspicious areas should be poked to check their integrity, and
pressure-testing should be employed if there is doubt. Some tanks are not installed correctly on raised pads, and water can be trapped under the tank, causing rust or corrosion.

As a point of reference, replacing fuel tanks on a 46-foot, twin-engine trawler could hit $80,000, including engine and systems removal and replacement.

Fluid Samples

A good surveyor will draw fluid samples for the engine and generator oil, transmission oil and coolant. The samples will be sent to a lab for analysis, and will tell a great deal about the internal workings of the engine.

What should you do if a sample comes back with a severe rating? This can be a high-stakes question. It depends on what the lab is saying is wrong, and on other symptoms. If the engine is running well, reaching wide-open-throttle and not overheating, yet there is a trace amount of water in the oil, there could simply be a pinhole forming in an oil cooler. On the other hand, an engine with strange noises and bearing material in the oil could need a full rebuild.

It is rare that a sample on its own will kill a deal. An owner who can supply five years’ worth of sample reports, along with the current one, can show any trends that may be forming. A bad sample should prompt further diagnosis before a potential buyer is comfortable with the engine.

Another note about samples: They are only as good as the information that goes with them. Make sure that whoever pulls the sample knows how to get a clean sample. Also make sure the person knows how many engine hours are on the fluid, what brand and type of fluid it is, and the engine’s brand and model number. The more accurate information the lab has, the more information it can feed into its extensive library for comparison.

Blisters

Boats built more than 30 years ago often had polyester resin to bind the fiberglass. There were different chemistries of this resin that were more- or less-resistant to blistering. Poor laminating practices also contribute to blisters.

If a boat has only a few blisters, then spot repairs may be in order. Extensive blistering requires some thought. And, if there are no blisters on a boat bottom at survey, that doesn’t mean that there’s no risk. A boat with a repaired bottom can be a better boat than one that may yet blister.

Consider a boat that lived its entire life in fresh water on the Great Lakes. It spent three or four months a year in the water, and the rest in a heated storage building. If you bought that boat and moved it to Florida’s warm salt water, you might find a load of blisters the next time you haul out.

The only way to know how deep the damage extends into the laminate is to perform a patch test. The yard will grind off the bottom paint in a 6-inch circle and check it with a moisture meter. If it still reads wet, the yard will grind off the gelcoat and check again. A wet reading will indicate that the first layer of glass needs to be removed. If it’s still wet, a second layer of glass will be removed. It is typically not necessary to grind below this level.

The repair would be to peel the bottom paint, gelcoat and up to two layers of wet glass from the bottom, and then rebuild it with new fiberglass and vinylester resin that is more resistant to moisture intrusion. This work would be followed by several coats of barrier epoxy as an additional sealant, and a tie coat with the antifouling bottom paint.

Most boats these days are built with vinylester resins or epoxies below the waterline that are much more resistant to blisters, but not completely immune. Mistakes in the lamination process can still happen. It is more difficult to control the environment in open-air molding, and dust, wind or uncontrolled temperatures can cause problematic laminations. Similarly, poor techniques while infusing hulls can cause improper curing or voids that can lead to problems.

If the rest of the boat is what you want, then blisters don’t have to kill the deal. In fact, finding them may be a good thing. If the work is done at a reputable yard, the new bottom will have a warranty, and chances are there will be no future problems. In most cases, the seller will kick in half or more of the cost to seal the deal.

It’s important to know how extensive the blisters are, and to have the yard give a repair estimate before you buy the boat. Typically, the buyer pays for the patch test, and either repair of the test holes or the full bottom job.

To Buy or to Pass?

A major point to consider is how soon you want to use your boat. If your plan is to buy a boat that needs work and upgrades, then scheduling time in the yard to complete the tasks may not be an issue. Quite a few people enjoy their time in the yard, setting up the boat the way they want and watching as systems get replaced and renewed.

Conversely, if you want to buy a boat and immediately start cruising, then you may want to wait for a boat that has fewer issues. All boats need something added or repaired; you may be capable and want to fix things yourself. If you aren’t, then you should know that most decent yards have waiting lists. Even relatively simple tasks may take months to schedule and complete.

The decision to go or no-go on the purchase often has more to do with the cost to remedy the survey findings. Let’s assume that the boat has leaking fuel tanks, or perhaps a blistered bottom. Repair costs could top $40,000 for either of those problems. If you obtain a repair estimate for $40,000, can you expect a $40,000 price reduction?

Perhaps, but the reduction is usually less than the full estimate amount. If the seller had installed new fuel tanks before listing the boat, then the boat would have been advertised with new tanks, and the value would have been higher. On the other hand, as the buyer, you have to deal with the hassle of getting the work done, and the risk of a higher final cost.

While there is no general rule, 50 percent of the repair cost should be the minimum, and 75 percent would not be unreasonable. Most deals fall somewhere in the middle, with the final number factoring in the overall price and condition.

Our couple with the blistered boat decided to have the yard perform patch tests, which determined that the blisters were limited to the first layer of laminate. Armed with a quote from the yard, they negotiated a price reduction with the owner and bought the boat. A few months in the yard over the winter allowed them to have the bottom repaired, upgrade the electronics and spruce up a few other systems. 

This article was originally published in the November/December 2022 issue.

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