When I leave the boat I always shut the thru-hulls. It’s what I’ve been taught as best practice. But I have a dilemma about the cockpit drains. On my 26C the cockpits drained through the transom but on my 30U they drain below the waterline. I have been leaving these thru-hulls open but having spent many hours last evening saving a friend’s very large, modern yacht from sinking at the dock I’m questioning if that’s the right thing to do. So, 1) What do others do with their cockpit drains if they drain below the waterline- do they leave the thru-hulls open when the boat is at the dock? ; and, 2) Why would they have changed the design to move the drain from the transom to below the waterline?
My 30U (#211) doesn’t have seacocks on the cockpit drains and they aren’t below the waterline when they boat is at the dock. The relative positions of the drains and the through hulls make it hard to see how they could be made to fit.
Whole other debate, just my opinion…
Given the our boats are not recommended for offshore work in the first place and mine for sure will never be pooped by a following sea, I would suggest that the safest way to treat the cockpit drains would be to seal the hull openings and let the cockpit drain into the bilge. Maybe not the perfect solution but IMHO the danger of sinking is far greater from one of the through hulls or hoses failing unnoticed than from whatever water might make it down the cockpit drains. I’d rather pit my bilge pump against the latter than the former.
Unfortunately I doubt that either ABYC or the insurance community would share my view.
You could just put in two new through hulls on the transom above the waterline, like Pauls and mine are. Not terribly difficult to do, maybe possible to do even if boat is in the water. Reasonably easy transom access from inside cockpit locker. Just a suggestion.
Mine aren’t on the transom Don. They are a few inches above the water on the bottom. There really isn’t much way to put a seacock on them and if you did they would be difficult to access. They are submerged under power and sail. I can’t actually believe they built them this way.
Yeah you’re right. I was just in my locker greasing rudder post, mine are the same. But I don’t see why they couldn’t be through the transom as is the exhaust, propane locker vent, etc. So long as water doesn’t collect in the hose and freeze in the winter… for those who have to worry about such an event.
You would figure all the 30s would be the same. My scupper hoses exit “down”, but above the water line.
When we sailed her to her new home we had a long starboard tack from Norwalk toward the Throgs Neck Bridge. That put the port scupper in the water. We heard the Bilge pump come on and discovered split in the hose just above the through hull. We switched tacks to get it out of the water. Reversed the hose so the split was at the top and put a bung in the scupper. We went back to the starboard tack and replaced the hose when we reached the Hudson.
My N36 has four underwater thru-hulls for the cockpit drains. The aft two are quite large (2"). The waterline sits right inside the valve: if the hose is removed and the seacock is open, the boat won’t sink, provided she is sitting still.
The forward two are standard size, 1.5" (38mm). These two thru-hulls sit deep below the waterline. They don’t just handle the drainage for the forward cockpit drains, but the side deck drains are also connected to them via a T-fitting.
Am I happy with this setup? No. What was my solution? I bought high-quality, heavy-duty hose that won’t degrade over time. The thru-hulls and seacocks were replaced with high-quality Marelon fittings. I think the chances of something going wrong are pretty slim now, but basically Neil is right: more thru-hulls means more risk.
