Cockpit drain reqirements?

[SailingHarmonie]

Originally Posted by Cyrus Safdari

The reason why a flexible rubber hose is introduced in btwn the hull and the cockpit is to absorb crash forces and not send the forces further up that can crack that tube which could be disastrous if the crack was underwater

LOL, Nonsense. The reason people use hoses is: (are you ready?): It cheaper to build a boat that way.

The boat has made two circumnavigations, has wel over 150,000 sea miles. and none of her 400+ sister ships have ever had such a problem. The boat builder has been making them this way for 40 years...

[Renegde_Sailor]

On my boat I went a different route, I have a huge cockpit which is 10' long, it only had 2x 1 1/8" id drains, I filled those and the through hulls solid, then drilled two holes in the back of the cockpit to which I ran 2 4" id tubes that come together in a comon plenum that exits above the water line via a 6" hole.

According to the math My cockpit will hold about 3500 gallons of water full to the brim, with the 2 4" drains, it can drain it completely in less than a minute.

I also built the plenum box with a removable top so I can service the rubber flap I installed in there to keep water from coming back in.


I am incredibly happy with the new system.

[Mg451]

Thanks so much

[Don C L]

It’s pretty rare you will find conditions that will threaten to flood the companionway, but if you do, you’ll (usually) have plenty of warning. I wouldn’t worry about preventing every drop from entering, but you might beef up the slots and slats, or switch to stout little doors. A splash now and then may come over and enter an open hatch and douse a chart table or quarter berth unless you have a dodger. A dodger is very good idea if you don’t have one, verging on necessity in my book.

[Mg451]

Yes i do have a dodger. Like the westsail 32s I have no cockpit comings that block water from the running all the way down the sides into the cockpit.

[Don C L]

Originally Posted by Mg451

Yes i do have a dodger. Like the westsail 32s I have no cockpit comings that block water from the running all the way down the sides into the cockpit.

Yeah I often got a wet butt sailing the DE38 from splashes coming over the windward side.

[Ballsnall]

Originally Posted by Mg451

Thanks maybe it is over kill and its a real tricky location to get to so im trying to talk myself out of adding three more difficult through hulls. And as your familiar with the downeasters cockpit ( more like a foot well) maybe ill take that advice and just add one more so each 1 1/2 drain has its own 1 1/2" through hull.

That would be my choice, just remember, if your in conditions with green water in the cockpit it's unlikely your boat will be sitting level so a lot of volume will be spilled out not drained, the wave pressure on the stern will likely cause water ingress through the cockpit drains or at the least limit the water from draining out.

To me cockpit drains are more a comfort thing to stop the 2 or 3 inches of water sloshing around in normal conditions.

[Carl-T705]

I have asked myself if my cockpit had just four inches of water in it, would I be threatened or just annoyed. I think just annoyed, so my thought is to raise the extra drains to three to four inches above the sole which would give a steeper drain angle and be easier to install and less worry about following seas. Then what do I Know, I'm just a kid

[nofacey]

Your existing drains with one additional 1-1/2” thru hull on straight runs will be fine.

[Mike Burch]

Originally Posted by Cyrus Safdari

The reason why a flexible rubber hose is introduced in btwn the hull and the cockpit is to absorb crash forces and not send the forces further up that can crack that tube which could be disastrous if the crack was underwater

Absolutely correct. That's why Lloyds forbid any such construction.

The original post says that the cockpit has two 1 1/2" drains teed together into one 1 1/2" outlet. So effectively the cockpit has only one 1 1/2" drain. That is not adequate.

The easiest solution is probably to instal another 1 1/2" outlet and thus give each inlet its own outlet. That would seem to be adequate for an 18000 (not 1800) cubic inch cockpit.

But if the OP feels that is still inadequate he could possibly change everything from 1 1/2' to 2". According to Poiseuille's Theorem of laminar flow, that would theoretically increase the flow rate in the drains by a bit over three times, though in the real world of turbulent flow it would be rather less.

[Renegde_Sailor]

Originally Posted by Don C L

It’s pretty rare you will find conditions that will threaten to flood the companionway, but if you do, you’ll (usually) have plenty of warning. I wouldn’t worry about preventing every drop from entering, but you might beef up the slots and slats, or switch to stout little doors. A splash now and then may come over and enter an open hatch and douse a chart table or quarter berth unless you have a dodger. A dodger is very good idea if you don’t have one, verging on necessity in my book.

+1 on the dodger, I have a hard dodger with windshield wipers on my boat, and it is a wonderful thing that was much appreciated this year sailing to Alaska and Back!


Especially out in Queen Charlotte Sound with some 16' rollers walking through!