Wednesday, September 9, 2009

Deck Leaks

If a boat owner tells you he doesn't have any deck leaks, you should interpret that as, "I haven't found any deck leaks recently." Or, "I am lying to you because I want to sell you my boat."

With the return of the rains to Seattle (we set a record last weekend...), the subject of deck leaks is entirely apropos. Why do boats have 'em, and houses not? I don't know, but it may have to do with two things:
  • Boat decks are flat. Well, OK they are gently sloped to shed water, but nothing like the pitches of the roofs on houses
  • Boat decks have a lot of penetrations, where house roofs have only a very few - and those are very carefully (albeit traditionally) treated (chimneys, plumbing vent stacks, roof vents). Boats, on the other hand have deck penetrations for handrails, padeyes for blocks, lighting fixtures, dodger support structures, lifeline stanchions, pulpits, masts, etc. I'd wager that just one handrail on Eolian has more penetrations than the average house roof has altogether. (And what about a boat with a teak overlay deck? In addition to all the penetrations on a standard fiberglass deck, the teak overlay will itself have hundreds of screws.)
So, it comes down to opportunity (flat, or nearly flat surface) and risk (lots of penetrations).

But whatever the reason, deck leaks are a reality. They can really be tricky to locate too. The water can enter and travel a long way before it exits into the cabin. Eolian has a vinyl headliner, which means that water doesn't damage it, but it can direct the water a long distance.

So, what is going on in this picture from two winters ago? There was water coming out of the headliner edge at the narrow teak strip. I had used (ubiquitious) blue tape to redirect the drips from the cabin side, down the tape strips, and into the bowls. Until you find the source, this keeps there from being consequent damage.

And what was the source of this leak? Well, there was a little hole where a small screw had been removed (apparently from an earlier generation of our canvas cockpit enclosure). This screw hole was located inside the cockpit enclosure, and had not been a problem for the previous 12 years we had been responsible for Eolian. However, the small stream of water that had channeled inside the enclosure changed course (a new speck of dust? Recent waxing? Change of boat heel due to emptying water tanks? Who knows). Now it went directly over the screw hole. Well some of it went over the screw hole, but most of it went into the screw hole. And came out in the cabin. It is absolutely amazing how much water can come into the cabin via such circumstances. Until I figured it out, I was dumping the bowls, full, twice a day. Yeah, it rains a lot here in Seattle.

I need to make up a large batch of gelcoat, color-matched to the finish of Eolian's decks. Once I have applied this, the leak will be permanently fixed. But until then, there is a small square of blue tape over the hole.

Sadly, this is not the only small square of blue tape. I really need to make up that batch of gelcoat.

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