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Waterlines: Chasing Leaks on Boats

Water, water everywhere, including the wrong side of the boat

Water, water everywhere, including the wrong side of the boat

Chasing leaks on boats is a time-honored obsession. Rule number one in all galaxies of the nautical universe through all of nautical history has always been the same: keep the water on the outside. When water somehow finds its way inside and you don’t know where it’s coming from, discovering its source so as to staunch the flow becomes a quest for the Holy Grail.

One of my first big quests was aboard Crazy Horse, my old Alberg 35 yawl. She had a habit, I found, of taking on large amounts of water whenever she was driven hard on the wind with her rail under for days on end. Though Crazy Horse was otherwise a very dry boat, I spent hundreds of hours and thousands of dollars trying to find and fix a leak that, in truth, rarely manifested itself and posed no real threat to my safety. After I first recaulked all of the caprail and then rebedded the entire hull-deck joint, the leak did get slower, but it never disappeared entirely.

Since then I’ve learned not to worry so much about deck leaks. After all, a boat pretty much needs to be underwater in the first place if it is to be sunk by a deck leak. Still, these can be more than just annoying. I remember, for example, a Swan 48 I once delivered to the West Indies that took on water very quickly once it was heeled hard over. Because it was a modern boat with very shallow bilges, it was A) impossible to pump the water out while the boat was heeled over; and B) too late anyway, as the huge puddle to leeward quickly drowned all critical electronics, which unfortunately were wired up together down low under the nav seat.

Of course, the worst leaks are those below the waterline. Traditional plank-on-frame wood boats are most likely to have these, but because they have so many, owners must learn to ignore them lest they be driven mad with anxiety. Once while cruising the Bahamas, I was invited to crew aboard an old wooden Bahamian racing sloop and was surprised to find our boat entirely submerged just off the beach the morning of the race. The owner, however, was not concerned.

“Best t’ing to do before a race,” he explained. “If you sink ’em first, they don’t leak so much later.”

Even so, our boat (after we refloated it) leaked well enough during our race that we had to take turns bailing just to reach the finish line. Fortunately, during the last downwind leg we jettisoned much of our ballast, which made things easier.

During my other major adventure aboard a leaky wooden boat, an old Alden schooner, the only thing that saved us in the end was an enormous gasoline-driven trash pump. The leaking in this case didn’t seem to be coming from any one place. Rather, it was coming from everywhere all at once. And indeed once we limped back to shore and hauled out we found half the planks on the port side of the boat were not fastened to the frame. All that was holding them in place was the caulking.

“I’ll tell you what happened here,” said the yard manager. “Last time this hull was refastened the crew took off for lunch, had too many beers, and when they came back forgot where they left off.”

Which is, of course, precisely the problem with plank-on-frame boats. With all those planks, all those seams and all those fasteners, all it takes is a few flaws in a very large matrix and you’re sunk—literally.

When sailing in vessels like this, as we discovered firsthand, pumps are very important. In fact, owners of planked wooden boats take the business of pumping the bilge for granted and nonchalantly track the health of their hulls by counting how many strokes a day it takes to keep everything above water. As long as the number isn’t rising, they figure all is well.

When it comes to pumps, no matter what sort of boat you have, “bigger is better” and “the more the merrier” are definitely the mottos you want to live by. This is particularly true if you sail a smaller boat. The smaller the hull, after all, the faster it will sink when the water on the outside finally does find a way in. 

September 2019



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