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Inspecting Older Sailboats

Looking out for these problem areas can save you time and money.

Sailboat Stored on Jackstand

In this article we examine problems specific to older sailboats. Because many of these issues involve rot, corrosion, or manufacturers' defects and are therefore not covered by insurance, finding them early can avoid expensive headaches later.

Rig and Mast

The 28-foot sailboat was sailing along in a fresh breeze, when the skipper heard a faint "pung." The skipper glanced up — and then watched helplessly as the top of the mast started tilting awkwardly to leeward. A mere second or two later, it crashed over the side (Claim 98372712).

To a neophyte's eye, a sailboat's mast and rigging looks like a delicate web of cables and aluminum (or wood), hardly up to the task of propelling the boat to hull speed. A sailboat's rig, however, is carefully engineered to withstand all the various forces on it. A single failure can bring the whole thing tumbling down. In this case, the cause of the dismasting turned out to be a chainplate that had broken below deck level. The top was still clean and shiny but the rest of it, the part that had been hidden from sight, was a black, corroded mess.

Chainplates tie the rig into the structure of the hull. On most boats, they are made of stainless steel, which is susceptible to crevice corrosion when exposed to saltwater in the absence of oxygen. On an older sailboat, corrosion often begins where the chainplate passes through the deck or down below where it ties into the deck structure. Inspect chainplates for corrosion and cracks, above and belowdecks — you may have to remove a liner and some trim to get to it.

Moving to the rig, inspect turnbuckles for cracks and make sure there's at least 3/4-inch of thread visible inside. Make sure all turnbuckles are locked in place with cotter pins or, better yet, 316 stainless steel welding rod. Welding rod can be removed quickly and easily in the event of a dismasting and doesn't snag sheets or passing legs. Carefully check terminal fittings (use a magnifying glass), especially those near deck level, which are more likely to stay wet and corrode. Stays should be inspected for "fishhooks" by wrapping some tissue paper around the wire and carefully running it up as far as you can reach — shredded paper indicates a broken strand. Inspect rivets on the mast and boom. If you spot any that are loose or broken, all of them in the area will need to be replaced. Bubbles on a painted mast are an indication that corrosion is at work, as is white powder on bare aluminum, especially where stainless steel is in contact with it. After repairing the corroded area, the barrel of stainless steel fasteners should be coated with a lubricant/anticorrosive like Tef-Gel, and the head isolated from aluminum with plastic spacers available at marine stores.

Most people have a natural aversion to hanging from a rope at the top of a swaying mast, but unless the mast is off, there's no other way to inspect it. Only go up the mast if you have some experienced hands below to help, you're confident of the halyards and shackles that will haul you up, and you can rig a second safety halyard. You can hire a rigger to take a look, but learning how to go up yourself could serve you well in an emergency.

Run the tissue paper up each shroud to find fishhooks. Check the spreaders for damage where they meet the mast and at the ends, and make sure each spreader bisects its shroud. Inspect the tangs used to attach the stays to the mast, looking for cracks and corrosion. Make sure no cotter pins are missing or damaged. At the top (breathe, and don't look down), inspect the sheaves for cracks or excessive wear. Spin each sheave and make sure it moves freely (you'll need to switch your weight from one halyard to another).

Check the tangs for corrosion or cracks and look for missing or broken cotter pins or rings. On the way back down, check the rivets or screws used to secure the mast track. When you're back on deck — and less wobbly — inspect the mast step if the mast is deck-stepped. If it appears to be sunken, the deck support may be corroded or have shifted. Keel-stepped masts are prone to corrosion around their bases because water usually finds its way into the bilge. Look for pooling water or white powder and cracks at the base of the mast.

Look for cracks around where the goosenecks for the boom and vang attach to the mast and around the fitting where the vang attaches to the boom. These may need to be replaced or reinforced on older boats.

If the boat has a bowsprit, don't forget that the bobstay is part of the rigging. Inspect it and its attachment points for any signs of damage or stress. A bobstay that has been rammed into docks repeatedly will fail sooner or later, and if a headsail is flying at the time, the whole mast could come down.

Fiberglass Issues

Nearly all sailboats built in the 1980s or later have a deck comprised of a core made from balsa or some sort of composite material sandwiched between two fiberglass skins with a layer of gelcoat on the outside to make the hull shiny and fair. Problems frequently arise with the core and with the gelcoat.

Rotted Core Due to Water Leakage

Water that leaks into the core can eventually cause rot.

The deck doesn't take its strength from the fiberglass, but from the stiff inner core. Over time, water can leak into the core through deck fittings, such as cleats, chainplates, and stanchions, which causes rot that can eventually turn the core into mush. A mushy core compromises the deck's structural integrity, and if large sections of the core are rotted, it can be all but impossible — and very expensive — to fix. Professionals use the handle of a screwdriver or small plastic hammer to tap on the deck, listening for signs of softness, something you can do as well. Pay careful attention to the area around fittings that penetrate the deck; a dull thud often signals a soft spot while a solid "thunk" usually means a healthy core.

A spongy feel as you walk the deck may be a sign of larger rotten areas. If you suspect a problem, contact a professional. Extensive core repairs are generally above the skill level of do-it-yourselfers.

Chainplates are all but impossible to make watertight, so pay special attention there. Not only can a leaking chainplate destroy deck coring, it can rot the structural bulkheads to which they attach below. A rotten bulkhead can give way, releasing the chainplate and bringing the whole rig down. In the case of the 26-foot sailboat above, a leak caused the chainplate to corrode, which made it fail under load. After you finish your deck inspection, go below and look for stains or other evidence of leaks through the deck, keeping an eye out for water-damaged bulkheads.

BoatUS receives the most complaints about gelcoat problems including crazing, cracking, and blisters. Gelcoat is a thin coating over fiberglass and easily cracks. Gelcoat crazing is common on some makes of sailboats like Islander and Ericson from the 1970s when gelcoat was applied in a much thicker layer than today. It looks like spiderwebs embedded in the gelcoat that don't penetrate the surface. Though unsightly, these are not structural, and it is not worth the cost of repair.

The thinner gelcoat on newer boats is less likely to craze but more likely to crack. Though rarely structurally serious, cracking can indicate excessive flexing and often occurs on unsupported decks or cabin roofs, around stanchion bases or cleats, or where the boat structure makes a sharp angle — at cockpit corners, for example. Gelcoat cracks around deck winches, cleats, genoa tracks, or a windlass mean the area should be further inspected. The fitting may need a backing plate to spread the load, or the area may need to be structurally reinforced.

Fiberglass hulls blister when water passes through the gelcoat layer and combines with materials in the resin to create an acidic mixture that expands, pushing the gelcoat into a dome. Though unsightly, blisters on older boats are rarely a structural issue and can be dealt with relatively easily. A new boat with a "pox" of blisters, however, should be avoided as this could indicate problems with the quality of the fiberglass layup.

Hull Fittings

BoatUS has received complaints about underwater fittings on some sailboats. Brass fittings contain zinc, which can leach out of the fitting over time, causing it to become brittle and porous and eventually break. Head discharge fittings tend to be particularly susceptible. Look for fittings that have a pinkish color or patches of white fuzz. Plastic fittings are also not suitable for underwater use and while few manufacturers would install them, a previous owner may have. Bronze and Marelon (a type of glass-reinforced composite) are the most durable materials for underwater fittings.

Cracked Plastic Fitting

A plastic fitting will eventually turn brittle and crack in the sun; if the boat is overloaded, it could sink.

Also check fittings that are above the waterline when at rest, but which may be underwater when the boat heels. These fittings are sometimes plastic and will degrade in the sun. A cracked fitting close to the waterline can leak when the boat takes on extra weight (snow, gear, extra passengers, and so on) and can sink the boat.

Keels and Centerboards

Keels tend to take a lot of abuse in shallow waters. Damage on the leading edge and the bottom indicates some pretty hard groundings. Often the interface between the hull and keel has some filler in it that is easily cracked, but unless the crack is substantial, it's usually not a problem.

Cracked Keel

A large crack, like this, means a hard grounding, which may have caused structural damage.

Centerboards are subjected to heavy loads, and the cable, pins, sheaves, and fittings that support them spend much of their time underwater. The serviceable life of the wire and fittings is affected by many factors: whether the boat is being used in salt- or freshwater; the number and severity of groundings; the compatibility of the metals used; and the weight/configuration of the keel/centerboard.

A cable that fails suddenly can be much more than an inconvenience; the centerboard can bash a hole in the hull and sink the boat. Swing keels and centerboards should be lowered completely (usually this is only possible while a boat is in the slings and positioned over a pit) so that the wire can be inspected for broken strands. Centerboard trunks should be opened and inspected when the boat is out of the water. Fittings at either end of the wire should be replaced if you see rust, cracks, or distortion.

If you're buying a boat, doing your own inspection can save you the cost of a survey by ruling out boats with common faults. But a self-inspection, no matter how thorough is no substitute for a marine survey, so hire a professional after you've done your own checkout.

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Charles Fort

Contributing Editor, BoatUS Magazine

Charles Fort is BoatUS Magazine's West Coast Editor. He often writes local news items for BoatUS Magazine's Waypoints column and contributes to Reports, in-depth tech features in every issue written to help readers avoid accidental damage to their boats. He is a member of the National Association of Marine Surveyors, he's on ABYC tech committees, and has a 100-ton U.S. Coast Guard license. He lives in California.