Okay, maybe that title is a bit melodramatic, because there are a million and one very old boats out there that are completely safe. It is without question, however, that as a boat’s age becomes measured by the decade instead of by the year, there are a few significant forms of age-related structural failure which can lead to big, big problems. What’s worse is that the long age-span of fiberglass means that there are more and more aging boats out there year after year, and what’s even worse than that is that many of the potential failures aren’t apparent to the naked eye—at least, not until a boat sinks. So whether you own an old boat or you’re considering a used boat purchase, be sure to looks for these issues.
- Stringer and/or Bulkhead Failure – This can take the form of separation from the hull, cracking and/or fracturing, and in the case of wood-cored stringers, the rotting away of their innards. The good news is that all of these issues can be spotted with a visual inspection; that includes rotted coring, because if the boat’s been used at all with rotten stringers, significant and visible cracking almost surely will have resulted. The bad news about stringer failure is that most of the time the stringers are hidden from view beneath a deck liner, which makes laying an eyeball on the critical areas difficult, to say the least.
If your boat or the boat you’re looking at has bilge access, in all likelihood you can get see the stringers from there. Use a flashlight, and look closely at where they meet the hull and bulkheads. Hairline cracks are to be expected, but anything big enough to slip the edge of a dime inside of is a sign of trouble.
What if you can see an area where the stringer has actually separated from the boats hull? The boat is unsafe, period, and needs to be removed from service immediately until some major-league repairs can take place.
- Hull to Deck Failure – Most modern powerboats, be they designed for bass fishing or bluewater, are constructed with a hull and a deck and/or liner. These major components are joined around the perimeter either with mechanical fasteners like screws and bolts, chemical adhesives like 3M 5200 or Plexus, fiberglass, or a combination of the above (hence the term “screwed and glued”). Then, the joint is hidden away behind a rubrail that encircles the boat.
If the hull and deck or liner separate, the results can be completely catastrophic. Just last season, a 32’ walkaround was in rough seas when the hull and deck separated, unbeknownst to the captain and passengers. With every wave, water poured in through the open joint. Eventually it filled the bilge. By the time anyone realized what was going on it was too late, and when a wave hit the boat broadside, it swamped and then rolled. Four people died.
Again, the toughest thing about finding deterioration in a hull-to-deck joint is the fact that it’s often difficult to look at. You can usually get an eyeball on it by inserting your head into an anchor locker, if there’s one with a big enough opening. And sometimes it’s visible from the bilge, looking up and to the sides. But it’s rare to have visual access to the entire joint, all the way around the boat. The only sure way to gain access to it 360-degrees around the boat is to remove the rubrail. You can replace any suspect-looking fasteners, and seal any gaps or questionable looking seams with a sturdy adhesive-sealant like 3M 5200. But when in doubt about a hull-to-deck joint, take the boat to a pro.
- Through-hull Fitting Failure – Though both metal and modern plastics certainly can and do fail—accidentally stepping on a seacock usually does the trick—through-hull failure is more often a problem with boats built with plastic parts in the late 80’s and the 90’s. Some of the plastics used through this time frame turned out to be susceptible to UV damage over the long-term. The worst cases pop up when a boat sits in the sun for very long periods, maybe on a lift or a trailer. The plastic can deteriorate without any real visible damage except perhaps a color change, yet become extremely brittle. As long as the boat’s afloat this usually isn’t a problem, but if the through-hull smacks against a piling or drags against a trailer bunk, it can shatter or crumble to bits in a heartbeat.
Check for through-hull deterioration by looking for significant color difference between the outside and inside of the through-hull. Cracks are obviously also a reason for concern. When in doubt you can test the plastic by giving it a mild rap with a hammer or the handle of a screwdriver, but if there’s any question, the safest thing to do is simply have it replaced.
- Deck Delamination and/or Rot – Any boat built with a ply-cored deck will probably need to have it cut out and replaced, at some point in time. Yes, there is pressure-treated ply with a lifetime no-rot guarantee. I used to own a 19’ center console built with the stuff, and after a decade or so, though it didn’t “rot” it did absorb water, flex, and delaminate from the fiberglass. That’s an extreme example, because plenty of builders get 20 or even 30 years out of a ply-cored deck. Still, sooner or later…
Silver Lining For Old Boats
There are two fortunate aspects to rotting, delaminating decks on boats. First, they’re pretty easy to find. Just walk all over the boat, and if the deck feels spongy or springy anywhere, it’s on its way to needing replacement. Second, cutting out and replacing a dead deck isn’t a massive job. Remember that 19-footer of mine? I had a fiberglass shop professionally replace the deck and it only cost around $1,500.
- Bad Backing Plates – If you’re looking at a boat that was well-built in the first place, it’s likely to have pre-tapped aluminum, phenolic (composite), or Starboard backing plates. If it was really well built, the plate was laminated right into the fiberglass. But quite commonly a faster, less expensive way to back a cleat or a rail is to use regular old wood. And again, the stuff rots.
Any hardware that’s lacking a backing in good shape should quickly become apparent. If, for example, a cleat moves one iota when you kick or shake it, something’s obviously wrong. And in most cases fixing the problem is quite easy; just pull a few nuts and bolts, add a new backing plate, and you’re good to go.