Thru Hull cockpit drain problems

[mike_kelly]

New boat, checked and found it had gate valves on the thru hulls. Always read that gate valves have no place on a boat. Fine I pulled them and started to get quite confused when trying to replace them.

The thru hulls are brass or bronze and one doesn't even look like it has a nut on it. I am not sure of the threads. I want to use Forespar Marelon ball valves which use NPT straight threads which I think are more correctly called NPSM. The gate valve was a B&K 200 WOG which appears to be ISP threads, which appear not to be compatible with NPT. The boat is 40 years old and British made a "could" have British Standard Pipe threads which are the same diameter and threads per inch as NPT but a different pitch.

The cockpit drains are wierd. They are very small, half inch, but the drain is actually 3/4 with this removable liner which reduces the size to 1/2". They looked to me like they were hooked up with garden house fittings. Nobody seems to make cockpit scuppers in 3/4" to match the rest of the drain system.

1. I am not sure how to determine exactly what threads the thru hulls are, Forespar Marelon Ball Valves will work on bronze thru hulls but the buyer must get the threads to match.

2. Why can't I find a matching new cockpit drain in 3/4", is it common to buy a 1 1/2" and then just use reducers to attach to the seacock?

3. IF I have to remove the old thru hull and replace them, how do you hold the thru hull body while turning the nut? Seems like after the bedding compound gives way the thru hull would just spin in the hull.

Thanks for your advise

[CharlieJ]

3. IF I have to remove the old thru hull and replace them, how do you hold the thru hull body while turning the nut? Seems like after the bedding compound gives way the thru hull would just spin in the hull.

Thanks for your advise

The last part I can help you with:) This was copied from something I sent someone long ago-

The normal way to undo (or tighten them) them really takes two people. Most of the thru-hulls have some little ridges or tits on the inside, You need a flat piece of metal that will just fit inside the thru-hull from outside and will lodge against those ridges. Then while someone holds the seacock from inside- might take a pipe wrench, you turn from outside to unscrew ( or screw in) the fitting, probably using a very large crescent to grip the flat metal piece..

[Travelnik]

No advice for you, but my 1969 Westerly Nomad (British) also has gate valves for the cockpit drains. I thought that maybe the PO put them in just to save a few bucks.

I plan on enlarging the drains on my boat, putting them through the transom.

I would like to hear the advice you get from the group.  ;)

BTW, welcome to the forum!

[mike_kelly]

Charlie, I have found an article on thru hulls that shows the wrench and the nubs it is used to lock to but unfortunately when look up into my thru hulls there is no such nub. I guess worse case i can drill a hole through the top of the thru hull pipe and put a long bolt thru it, move the nut up and drill one below the nut etc. Or just drill off the nut from both sides.

What a pain. If people would just do things right the first time.....

Dean, Thanks for the welcome. Looks like lots of practical small boat owner here.
I think now that I have taken more photos and done more research that these thru hulls were done completely wrong, at least by todays standards. The little beast is 40 years old so when it was built it may have be de rigur for the day. But it appears to have the typical problems of the wrong thread types mixed, the thru hull seems to be corroding like it was yellow brass rather than bronze, it had a gate valve on it and no flange.
I guess it is an opportunity to do it right and increase the size of the drains and thru hulls.

Cheers

[CharlieJ]

What a pain. If people would just do things right the first time.....

:D

As a retired boat builder and restorer, I couldn't agree more. That's why the term DPO exists- Dreaded Previous Owner. Some say D a m n instead of dreaded

[Leroy - Gulf 29]

I thought the D stood for dips--t ;D

[mike_kelly]

So if I have to replace the whole mess what size thruhull, seacock and cockpit scupper is best for a 20ft boat with a small cockpit? Since I don't have to consider adequate but have the option, other than the increased cost of larger fittings, to choose best.

Cheers

[CharlieJ]

Really up to you, and the boat set up.

On both of my last two, I made 1 1/2 scuppers. But then I tend to be offshore a good bit.

I would think at least one inch.

[CapnK]

Size - bigger is better, IMO. The only time I want standing water in the cockpit is if I were to be hosting a hot tub party... ;D

Regarding removing the old thru-hulls, a side grinder is a very quick way to do it. Grind from the outside, focus on cutting away the inner wall, so that the larger/main body of the exterior part simply falls away/can easily be pried from the hull/bedding compound.

Welcome aboard!

[mike_kelly]

I wonder if i could kill two birds with one stone? If you look at the drawing i posted of the boat in the thread above about the Outboard, if I opened the engine well again why couldn't I remove the thru hulls completely. Then create drain holes into the well from the back of the cockpit. Also I could put a small "sea chest", with the current forward cockpit drains and the sink draining into it. Then install a pump (with float switch) in the sea chest and pump the water from the sink and forward cockpit well back into the engine well.

Then I have no holes in the boat proper and I don't have to buy expensive seacocks and new cockpit scuppers.

????

Thanks

[SalientAngle]

Brilliant !!! I like the concept, grog to you !!!

[Snapdragon]

Here's a picture showing a similar conversion that I did on "Puff".  Fortunately the cockpit drains are at the rear of the cockpit near the motor well, so it made for a very short run of drain hose.  It also allowed me to glass over two through-hulls (seen in the foreground) and opened up the space under the cockpit floor for an amazing amount of storage/equipment space. 

[Bubba the Pirate]

I took gate valves off my Cape Dory. According to the research I've done, many manufacturers were installing them this way. They are NOT true seacocks.

A seacock is actually very different from a valve, gate or otherwise, screwed on top of the threaded mushroom cap thruhull. For strength and safety, a real seacock is flush against the hull with a built in flange that is bolted to the hull.

Some good pictures and description in Don Casey's article. Or google seacock and look at images.

Here's the Casey article:
http://www.boatus.com/boattech/casey/installing-seacock.asp

[mike_kelly]

Snapdragon,

Yes my way back to the engine well will be more difficult than yours but I am thinking it is worth it to get rid of the holes in the boat. Do you have any problem with the engine well drains being fairly close to the water line? Does the water in the well ever rise up during rough seas etc. Other wise has it been a good choice?

Sailorbum,
Thanks I had found that article and it is very useful.

[Snapdragon]

Mike, the cockpit drains enter the engine well about 6 inches above the water line, and I've never had any water at all enter through the drains, even in a heavy chop.  I don't have any offshore experience with this setup yet, but I'm confident that it won't be a problem.  Considering how much better I sleep when at anchor and how little I worry when I have to leave Puff unattended for weeks on end, changing those cockpit drains and filling those through-hull fitting holes with good solid fiberglass was sure worth the effort!!  I highly recommend it.

[mike_kelly]

Ya after inspecting my thru hulls I am really glad I got dragged down this path. They are really corroded and I probably would have ended up with the fishes. Since I have never had it in the water i don't know where the water line is precisely. So I think I will have to glass over the old thru hulls and then take her out and make the decision on where to place the new drains afterwards.

Like you I am sold on the idea of having no thru hulls!

Cheers

[s/v Faith]

Spent the day scrubbing out Faith's bilges and getting her cleaned up after cruising aboard Emerald Tide since the fall.

Noticed a bit of seepage from the "ball valves" on the cockpit drains. :(

So, of course the ball valves have to go.  I intended to remove them on the last haul out, but I ran out of time so I just replaced them.... They are going on this haul out, and after what I saw today that will be sooner then I had planned.

Pearson originally had fiberglass tubes glassed into the cockpit, and a matching set  glassed into the hull with a rubber hose connecting them.

What is the matter with that?  I know I was thinking of replacing the ball valves with seaCocks...  But why?

The cockpit drains are never going to be closed anyway...  What purpose would the valves ever have?

[Frank]

I remember looking at Revival's cockpit drain hoses there and thinking "there must be some flex in bigger sea's" and "how would I stop a leak...or a gusher from a cracked/broken hose". Seemed a potential trouble spot to me. But then.....how many have travelled how far for how long "as built" ?

[s/v Faith]

Yes, I like the idea of the seacock for that, but;

- having a seacock only works if aboard the boat when the hose goes.

- if hose goes when aboard, it is not that much harder to pound a damage control cone in the hole.

- hose failure seems exceedingly unlikely.  Even folks using automotive radiator hose are using hose rated near 20psi in a 2psi application....  Use heavy exhaust hose and your safety factor is pretty high....  Or use regular reenforced hose and even if you changed them every haul out you could change them for 49 years for the price of the seaCocks....

Has anyone ever experienced, or heard of a cockpit drain hose failure sinking a boat?   I know Ariel's have sunk for sink drain failure, I want the sink on it's own dedicated seacock I can keep closed when not in use.

[Captain Smollett]

A possible advantage of sea cock over damage control plugs is...

I can close the sea cocks in a rain storm and let the cockpit will with water for built in cockpit pool / bath.   8)

Yeah, yeah...can plug the drains from the top; I thought of that.  I tried to make a point that makes sense.   ::)

Still.  I'm putting big old honkin' flanged sea cocks on my cockpit drains.  Practical or not I guess can be argued either way.