Mast Leak and Repair

One night we were sleeping with a nice rain outside, well maybe it wasn't that nice because it was the leftovers from one of the Hurricanes in the summer of 2005. I woke up at anchor because of this drip, drip, drip on my head. No, I wasn't having torture at the time although I sometimes think that having a boat is torture because it always seems you are fixing something. This time the problem was tracked down to water coming into the boat from this tube going up into the mast. We headed back to the dock and since it was Sunday and still raining my only choice was to set up a drip system to catch the water while I called and emailed to see what the problem was.

Fortunately a friend was staying down all week and said he would empty the bucket if necessary.


I called Performance Cruising for their recommendation .

I also emailed the Gemini list for their recommendations. What I found from both was the water was building up in the mast and then it was coming down the tube you see to the right. In the manual it said the tube was 5 inches tall and the purpose was to keep the water out. According to people on the list, if there isn't a drip leg on the wiring the system doesn't work. Well even if there is a drip leg and you have a lot of rain before the standing water can evaporate, you still have a problem because the water builds up and goes down the tube and yes drips on my head.

The recommendations from all sources were to drill two holes in the mast, one on both sides so the water doesn't build up. Second, seal the tube in case there isn't a drip leg with something that can be taken out if you take the mast down. So that is what I did.

First I used a coat hanger that I cut out and measured the distance to the top of the tube. The reason I did this was the differing opinions of how long the tube actually is. Well I don't know about the other boats but in my boat the tube is 5 1/8" long.

The next step I took was to spray in Great Stuff expanding foam into the tube. This was to fill the tube in case here wasn't a drip leg and stop the water. However, foam isn't totally waterproof so there had to be two other steps.

The second step was to fill the end of the tube with connector sealant which will seal off the tube but won't get hard. This should keep the water from dripping on my head but I was also concerned about the water that could and has built up in the mast.

The final step was to drill a hole at the bottom of the mast to drain any water out of the mast. PCI had told me to be careful as I was drilling into the mast so that I only penetrated the aluminum on the outside and not the inside of the mast. (Nov 08 update - I'm not sure there is a stiffener in the mast or if PCI was talking about the aluminium tube that the wires go through.) You can see that I used a small drill first and once I got through the first layer I marked both the pilot drill and the 1/4" final drill. You can also see the results of water coming out of the mast once the hole was complete. (Another Nov 08 update - When I ran a screwdriver in the hole, I found it had plugged up with dirt and more water came out. Therefore, I will now check this annually to ensure the hole is open and the mast drains to the deck.)

Web Page by Jim Faughn