Monday, July 30, 2012

Fixing the leak

After a first effort to fix the leak and a trip to Europe, I had a second launch and sailing trial.  There were no big rigging errors but rigging the boat still took a while.  The wind was quite a bit slower and the sailing less exciting.  The leak too was slower and the hand-operated bilge pump kept things under control, but the boat still took in water.  Three weeks ago I launched the boat again in the local reservoir, without rigging and with the forward floorboards removed.  The leak was slow enough to make it difficult to diagnose, but I had my suspicions.  The water mostly came in on the port side, and that of course is where I built the ballast box.  One end of the bolt on which the CB pivots lay inside the ballast box, and I came to suspect that I forgot to ensure that it does not leak.  My previous boat has a significantly shallower draft and the bolt is almost always above the waterline, which probably made me too complacent in this case.  My fear was that most of the leak was coming right through the ballast box, soaking the lead shot every time the boat got in the water.   This would inevitably cause corrosion. 
So for many reasons it couldn’t be helped: I had to remove the middle floor plank covering the ballast box and check things out.  So I did, sitting inside the boat while it sat on its trailer.  I saw that the lead shot was showing signs of corrosion already.  I removed the lead and poured water into the ballast box as a test.  I discovered that both forward and aft compartments had gaps along the seam where the side wall met the keel batten, which leaked water in and out of the ballast box, but that did not explain why the boat itself leaked: no water dripped out of the bilge onto the floor.  Then I tested my hunch that the leak may be through the CB pivot bolt hole.  Sure enough, as long as the water level inside the compartment was above the bolt, water trickled out onto the floor in a good-sized stream.  Gotcha!
To remove the bolt I had to cut up and remove the port side wall of the forward ballast compartment.  It was a lot of work, but it could have been worse: the fit was so poor that it wasn’t even glued to the keel batten.  I took out the CB pivot bolt and the CB itself and cut a new side wall.  The next day I epoxied the side wall and puttied several seams that allow water to spread along the bilges.  The third day I replaced the CB and its bolt, making sure I used rubber gaskets and caulk on both sides, plus I glued and nailed the side wall and gave it a second coat of epoxy.  The fourth day I re-caulked the inside of both ballast compartments.   The caulk I used took a couple of days to dry, and then I tested the compartments again for water tightness.  Alas, the bolt hole still leaked.  I used more epoxy compound between the bolt and the CB case, then tightened the bolt and tested again.  By now the leak had been reduced to a slow drip.  After another dollop of caulk (silicone this time) had dried it was time to test again.  The leak had slowed even more, but was still there.  Back to the drawing board. 
So I removed the bolt again (through a hole I had to drill in the compartment side wall) and found the continuing problem.  The pivot bolt goes through cedar, a soft wood that deforms when compressed, plus the epoxy compound I had used had not hardened properly.  So I glued a square piece of marine plywood an each side, slathering plenty of epoxy compound to be on the safe side, and used a longer bolt with neoprene-on-steel washers.  Then I plugged the hole in the side wall with a cork, and tested for leaks again.  Success, at least for now.  Then it was time to finish the job.  After letting the compartments dry, I coated the lead shot with mineral oil to prevent further corrosion and packed it in double layers of Ziploc bags.  Then I replaced the middle plank.  With a bit of luck all this will be sufficient to stop the leak and keep the lead dry. 
This is what happens when you don’t do things right in the first place.  I had boasted that the only thing I had to do over was the oar blades.  Can’t say that any more.  But without mistakes you can’t experiment or learn.  The expense was annoying, because somehow I had timed my purchases so that there was almost nothing left over: I needed disposable gloves, epoxy, wood flour, epoxy measuring cups, brushes and lumber.  These plus a new bolt and washers and Ziploc bags added up to just over $70, including exorbitant shipping fees.  I’ll put that and the 20 hours of work (spread over two brutally hot weeks in a garage with no A/C) down to experience. 
If I was starting from scratch knowing what I know now, I might have foregone the ballast box completely and simply strapped lead bars or ingots to the keel batten, after testing the boat for leaks.  I would have also slathered more epoxy between CB trunk, keel batten and bottom and filleted more carefully every seam that could possibly enable a leak.  But I feel that the two-week-long repeated diagnostic, repair and retrofit process taught me a lot and, hopefully, was successful.  So, after returning from my daughter’s wedding in San Francisco followed by a trip to Paris and Belgium, I expect to relaunch Aerie and, knock on wood, not have to worry and bail any more.