We recently hauled out our 1974 Islander 30 MKII to repaint the bottom. While we were out, we checked all the thru-hulls, the prop, etc. Everything looked fine. We went in the water and acquired a pretty good leak. It is not coming in any of the thru-hulls or around the shaft. Has anyone ever had a similar mysterious leak happen? Help, it's driving me nuts trying to find this leak, which is allowing approximately one gallon per hour every one to two hours.
Mark Matthews responds:
Thanks for the question. I can empathize with your situation. Theres nothing worse than emerging from hard toil in the boat yard only to be in worse shape off than when you first went in. If its any consolation, while changing a cutlass bearing, I once had to take the stern tube out. Somewhere in the activity, I forgot to put 5200 on the inside flange. It wasnt till we were back in the slip that I had realized the error, and although I was eventually able to rebed it, the bottom line is that these things are best done when the boats out of the water.
In your case there could be any number of things wrong. For starters get a flashlight, take a deep breath, and start crawling around the inside of your boat. Start with the thru-hulls. Shine, look, and feel for water making its way under the backing block, through the handle, or through a hose that has been cut by an over-tightened hose clamp. If anything seems damp, wipe it down with a paper towel until it's dry and wait.
Search methodically. Inspect the engine, sink, head, and cockpit scupper hoses too. Anything that has a cut, nick, or is chaffed below the waterline will allow water into the boat. Dont forget the water strainer for the engine too, and engine water pump or any other connection that brings water into the boat, like air-conditioning pumps. Tasting the waterprovided you are in salt watermay also be illuminating. Dont rule out a leaking water tank or hot water heater.
Check the shaft too. In conventional stuffing box arrangements, the packing gland should leak a drip or two every minute. More than this and it either needs tightening, or the packing needs to be replaced.
Check the rudder post. On many boats this is essentially a vertical flexible stuffing box with the rudder shaft coming out of it. If its none of these, the only other culprit left is the keel bolts. Heres hoping for a simpler solution.
For more advice, I'd recommend subscribing to the Islander e-mail discussion list, where you can benefit from the experiences that other Islander owners have been through. Here's a link that list: http://members.sailnet.com/email_lists/