Cockpit Drains

[SimonV]

Hi all

It would seem you yanks like things small, I have noticed the cockpit drains on a lot of boats are lucky if they are 1-1/2" in dia. Now what would be the best way to replace them with 3"' or better 4" dia drains, say on an Islander 36. Would you just glass in some pvc tube? I have been to the on line boat supplies and they just don’t do through hull fittings in that size.

[PBzeer]

4" would be a pretty big hole to try to plug if the thru-hull failed. I have 4 1 1/2" drains that go to 2 1 1/2" thru-hulls and my cockpit drains pretty fast. 3-4" seems like overkill.

[HerbDB]

My center cockpit beneteau 36CC has two three inch drains that go straight down through the engine room. The system has hoses above the water line. They connect to glassed in tubes that exit below the waterline. I am not sure how they are made, but the exteriors of the tubes are fiberglass. There are no through hull fittings or shut off valves. I would not trust pvc for this type of application unless there was a shut off valve; too brittle.

[sailingdog]

Some boats don't require large cockpit drains because the back of the cockpit is essentially one large drain... like on Alex's Giulietta. On others, the cockpit drains are undersized, but even a 3" hole is an awfully large one. One reason not to oversize cockpit drains too much is that you don't want the drains to be a hazard. If I stepped on a 4" drain, my foot would probably fit in it. Cockpit drains, by their function, shouldn't have a strainer or grate over them as that would allow them to be blocked far too easily.

Any cockpit drain that doesn't lead directly overboard needs to be inspected regularly, as the hoses for them should not sag and need to be double clamped on both ends—otherwise a wave that poops the boat can end up in the bilge—not what you want.

The size of the drains is also determined by the size of the cockpit. The cockpit on my trimaran is relatively small and drains well through two 2" drains. I'm planning on modifying the cockpit later this season and relocating one of the cockpit drains, as I'm glassing in a new storage locker in the cockpit to create a bridgedeck.

[Valiente]

I have a shallow cockpit on an otherwise flush aft deck. It's about the size of a half-bathtub of the kind you see in small apartments. No lockers, no levers, no gaps. The wheel is a good 30 centimeters higher than the highest possible level of water in the cockpit.

Two three inch metal pipes drain down and directly aft, but well above the waterline. I prefer small cockpits or those that can shed weight.

I plan to weld in padeyes for tethers, but it's built to take a big wave on the stern without pressing the boat down too much.

[sailingdog]

having a steel boat has some serious advantages, like being able to weld stuff to the deck and not have to futz with potting the cored section with epoxy or making backing plates... But corrosion never sleeps.

[SimonV]

So I get the consensus is to go with extra drains rather than larger drains.