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-   -   Cockpit drains (http://www.sailnet.com/forums/sailboat-design-construction/62370-cockpit-drains.html)

theartmkr 02-26-2010 02:35 PM

Cockpit drains
 
Ok you boat (re)builders. Here is a question. I am rebuilding a 1961 Champion 21 (see rebuild photos at: http://billsboat.webs.com). My cockpit sole is about 4" above the waterline. Should I install ridgid pipe (schedule 40) glassed into base of cockpit sole, extending vertically THROUGH the bottom of the hull (glassed in at hull)? This would let water drain quickly (especially if I used two 2" drains). Option #2 would be to use hoses connected to cockpit drains and then to through-hull right at waterline. I guess option #3 would be to use hoses from drains to seacocks below waterline. Any thoughts would be appreciated.

bill

sailingdog 02-26-2010 04:04 PM

If you're going to go with PVC pipe, I would go with schedule 80, rather than 40, since it is stronger...and I would recommend using epoxy resin to glass them in, rather than polyester or vinylester, due to the stronger secondary bonding characteristics. You might also want to glass around the entire pipe, all the way from the cockpit to the hull, however, if you do this, you can probably drop down to schedule 40 pipe. :D

If you decide to use hose, rather than PVC pipe, I would recommend putting in a seacock.

theartmkr 02-26-2010 04:46 PM

so, sailing dog, do you think a straight through pipe is better or a hose? And if I did use hose below waterline.....definitely would use seacock, but you think I would still need to use them if I were right at the waterline?

tager 02-26-2010 05:20 PM

I don't totally understand why, but some advocate crossing your cockpit drain lines. Port to starboard, starboard to port.

jrd22 02-26-2010 05:32 PM

Quote:

Originally Posted by tager (Post 574504)
I don't totally understand why, but some advocate crossing your cockpit drain lines. Port to starboard, starboard to port.

That's done because you need the low side to drain when heeled. If the scupper in the low side of the cockpit is very close to the waterline it won't drain well and in some cases water will actually come in through the scupper if they are not crossed. You need to carefully lay out where the thru hulls need to go to to insure that they work properly.

I wouldn't use PVC pipe for your scuppers, go with the hose and seacock/thru hull.

amarinesurveyor 02-26-2010 06:04 PM

Bill,
Very cool boat! How about taking the cockpit drains straight out the transom as high as you can? Then it would make sense to cross the hoses.
Brian

Mechsmith 02-26-2010 06:22 PM

I would not bother crossing lines. Standard cockpit drains are too small anyways for serious blue water work. If I had all my druthers I'd have an eight inch checked drain out the back. (look at one of the Coast guard RIB's) The ones with the 50 calibre mounted in front!

The reason for not using schedule 40 or 80 PVC pipe is that it is too rigid and you must allow for some flexing between the cockpit floor and the hull.

I have 1 1/2" re-enforced neoprene fuel hose with barbed and clamped bronze fittings and thru hull. There is one on each side of the companionway in the corners of the cockpit. one elbow (90 degree barbed) and one "T" leads to the single through hull which is just above the waterline. This was factory on my Seafarer 29.

Re crossed drains. The lower cockpit drain would not drain when heeled anyways. The outlet would be higher than the drain. The upper outlet won't have any water near it.

The hose is available from most autoparts stores (NAPA in my case). Use fully stainless hose clamps (hardware store NOT automotive) and double them up. After installation put a bit of silicone adhesive sealer on the screws so that they cannot work loose. You could also use reinforced auto radiator hose as that will safely last ten years or better out of the sun.

My Seafarer 22 has only one drain in the center of the cockpit that is lead straight down to a through hull in the centerline. Hose again between them.

Mechsmith 02-26-2010 06:29 PM

PS. Dont use the wire re-enforced automotive hose. The wire can't stand plain water.

jrd22 02-26-2010 08:17 PM

Quote:

Originally Posted by Mechsmith (Post 574525)
Re crossed drains. The lower cockpit drain would not drain when heeled anyways. The outlet would be higher than the drain. The upper outlet won't have any water near it.

Umm... I guess most of the world's sailboat designers are wrong then? Mine seem to drain quite well when heeled over, must be something wrong :rolleyes: .

Do NOT use automotive hose for below water line use unless you have the boat well insured. Use USCG below water line hose only. Available at marine stores or online.

bubb2 02-26-2010 09:32 PM

Quote:

Originally Posted by Mechsmith (Post 574525)
I would not bother crossing lines.

Re crossed drains. The lower cockpit drain would not drain when heeled anyways. The outlet would be higher than the drain. The upper outlet won't have any water near it.

My Seafarer 22 has only one drain in the center of the cockpit that is lead straight down to a through hull in the centerline. Hose again between them.

This maybe it's a little boat thing when you said you would not cross the cockpit drain hoses.

If fact they will drain faster crossed then if they were not. As the thru hull here the water is exiting is not in contact with the sea when the boat is heeled. The water draining from the cockpit does not have to over come the surface tension of the sea in order to drain. Thats way it's done with crossed hoses.


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