Cockpit scuppers

[sanibel sailor]

My cockpit scuppers are adequate for heavy rain or a big splash, but I doubt they would quickly clear a heavy load of water from the cockpit. I suspect the same of most production boats. Low priority at the moment, but it is on my mind.

Two drains at the forward corners of the well. There are grates to keep small objects aboard. The drains are nominal 1-1/2" fiberglass tubes, although I suspect an ID closer to 1-1/8", then 1-1/2" hose strait down to a seacock.

Problems/thoughts- 1) grates restrict flow quite significantly, but are fairly important. 2) Does not appear that grate openings can be enlarged much. 3) FG tubes with smallish ID, but likely a challenge to enlarge to bigger tube due to joinery in the way. 4) Could install a flush style 2" thruhull in floor, but would require fabricating a new grate of some sort as well as a adapter to the 1-1/2" hose in a tight space.


5) Low companionway sill (and engine access hatch in floor) accentuates potential problem, but that solution is for another thread.

Solution I am considering-
Installing two drains in the aft wall of the cockpit well (just above floor level) with only a welded mesh screen as a grate, leading straight to a thruhull in the transom. Might require a swing style check valve to prevent water coming backwards.

[AKA-None]

I believe that's why the open transom has become so popular recently.

Make sure the new drains work while healed. E.g. The outlet needs to be lower than the inlet when healed.


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[sanibel sailor]

Down below

[Stumble]

If you are going to go thru the bother of adding drainage then I would suggest adding enough to meet the ABYC standards for draining cockpits. They basically require enough drainage to empty the cockpit 75% in 90 seconds.

See Gords post here Cockpit Scuppers Size and Hose material [Sitemap] - Cruisers & Sailing Forums for more information.

[wsmurdoch]

We have screens (really punched stainless sheet metal discs) over our cockpit drains to keep dropped things from going into the maw of the deep blue. But, when we are offshore, or when we are not on the boat, we remove them to help the cockpit drain faster, much faster.

[Cheechako]

On a boat I had I put in two 4" drains in the back of the cockpit (on the vertical lazarette wall) with hose running to exits on the transom. Though they aren't on the floor, each one is 7 times bigger than a 1.5 scupper. Even four 1.5 scuppers drain very slow. (I've seen video testing in the water) The good news is most boats float with the cockpit full of water.

[sanibel sailor]

my grates clearly do not meet current standards.

If you count my sill as about 6", I have no trouble meeting the drainage requirement; above that, it all just drains below quite quickly.

Do they mean cockpit seat height or lowest point on the coamings?

[zeehag]

if you ditch yer grates i will take em.... i can find a use on my fat bottomed girl.
realistically, have you tried to elevate the grates??? shouldnt be too hard. after all, bristols are decent deep water boats, are they not. and designed by an adequate designer???

[Stumble]

Originally Posted by sanibel sailor

my grates clearly do not meet current standards.

If you count my sill as about 6", I have no trouble meeting the drainage requirement; above that, it all just drains below quite quickly.

Do they mean cockpit seat height or lowest point on the coamings?

First instal non-leaking hatch boards. Then the test is based on the maximum volume of water that could be in the cockpit at one time. So the lowest point of the seat back, or coming depending on the design.

[sanibel sailor]

Originally Posted by zeehag

if you ditch yer grates i will take em.... i can find a use on my fat bottomed girl.
realistically, have you tried to elevate the grates??? shouldnt be too hard. after all, bristols are decent deep water boats, are they not. and designed by an adequate designer???

Had not considered elevating the grates. Right now I race the boat, so there is a lot of traffic right there, but that may be a good solution when heading for open water. If I replace them, you got first dibs.

Designed by Ted Hood, although I understand it was actually Dieter Empacher's work while he was at the firm. I think it comes down to the level of detail provided by the designer. Probably the number and size were spec'ed, but not the exact details which were left to the builder's discretion.

[svGenesis]

I was looking at mine the other day (center cockpit) I have 4-1 1/2" scupper holes, 1- in each corner, below they join into 2 (fore and aft) then run down into the thru hulls. My question is why not plumb these out the side or aft above the water line and decrease the odds of a thru hull/hose/clamp failure?

[clockwork orange]

Its astounding what some builders will do, I once owned a nice little C&C 24 where the back wall of the cockpit was parallel to the transom with only a 4" space between and a foot above the waterline and yet the builder chose to slope the cockpit sole toward the companionway to 2 x 1.25" drains which merged in 1 x 1.5" seacock. wtf.
I don't know the layout of your Bristol but if at all possible can you run a couple of solid tubes through the lazzarette and through the transom. They can just be in addition to the existing ones and take over if the cockpit gets filled. I have used vinyl down spout material as a form and wrapped it in fiberglass to make a strong fiberglass tube that you can glass in, it is not important that it bond to the vinyl as its only a form but you leave it in, rectangular has more area than round.
I am going through the same thing with a customers Hans Christian 38T at present, shockingly inadequate drainage despite the reputation. It has a stupid little well which I suppose someone told the designer was required on a "bluewater boat" but they forgot to point out that having big high comfortable coamings that are as high as the trunk cabin that remain the same height all the way around the stern would hold a huge amount of water with nowhere to get out except down the companionway. The boat has 2 x 1.5" drains at the aft end of the well but the boat sits bow down with chain rode so someone installed a 3/4" drain at the fwd end to drain the cockpit when at the dock. it doesn't work. The side decks are just as bad as the huge bulwarks can hold thousands of gallons with a single 1.25" drain each side, very unseaworthy. We have installed large freeing ports through the bulwarks that are 7" x 3" approximately. Lots more to do. As someone else pointed out the best cockpit drains are an open transom, you can safely have a large comfortable cockpit at anchor as long as you have an open transom.

Steve.