SailNet Community

SailNet Community (
-   Gear & Maintenance (
-   -   Drains, valves, and seacocks: weighing the alternatives (

Rusty123 10-31-2012 04:57 PM

Drains, valves, and seacocks: weighing the alternatives
As I posted in another thread, my recently purchased 1981 Spirit 28 does not have any sort of isolation valves for the cockpit drains (which are below the water line) nor the bilge pump overboards (which are not). The hoses are connected to 1-1/2" barb-type through-hulls, which appear to be Marelon.

While the bilge pump hoses appear sound, the cockpit drain hoses are pretty sketchy - thin wall wire reinforced, with plastic "cuffs" (look like vacuum cleaner hoses). One is also a little short, so it's slightly skewed on the barb (although it is double clamped, and doesn't leak).

Ideally, I would like to replace all the through-hulls with proper seacocks. However, I don't plan to haul out until spring at the earliest. But I'm nervous about those drain hoses, so I don't want to leave it as is for any longer than necessary.

I've modified a plumbing pressure test plug to fit security in the outside of the through-hull, so I can make some minor modifications in the water. Here are the options I can see:

1. Replace the cockpit drain hoses with better quality, correctly sized replacements, and then install seacocks at next haulout. This would be the cheapest and easiest (at least in the short term), but would still leave the drains vulnerable to a hose failure (freezing, for example) in the meantime, and with no way to isolate drains or bilge discharge in case of a calamity.

2. As a temporary measure, install Marelon ball valves on the existing through-hulls (I would need to cut off the barb section of the through-hull, but there appears to be plenty of threads available). But ball valves are plenty expensive (over $100 each - almost as much as seacocks), so I'm reluctant to make that investment, only to replace them with seacocks in 6 months.

3. Install the ball valves as described above, but as a permanent fix. If I went with this option, I would trim the through-hull such that the valve is snug against the retaining ring, which would somewhat reduce the likelihood of snapping off the assembly.

Thoughts or suggestions?


asdf38 10-31-2012 06:00 PM

Re: Drains, valves, and seacocks: weighing the alternatives
I have a few thoughts,

On the one hand it sounds like your hoses aren't in great shape, but on the other hand how long have they been there? They're not leaking now so there is a case to be made to leave them until haul out.

Once hauled I suggest just getting the best components for what you want to do. If that's a proper seacock then do it. Don't skimp on the materials.

But I just don't see a strong case for seacocks here. You can't close them when you're gone so if you are and they spring a leak the boat's sinking anyway. How much time are you going to spend aboard? And if you're lucky enough to be there then you don't need the seacocks to fix the leak - you'll have other options like plugs, tape etc. So what do you think they'll get you?

Rusty123 10-31-2012 06:11 PM

Re: Drains, valves, and seacocks: weighing the alternatives
asdf38, you make some excellent points.

While I don't sail very often (particularly in the winter), I do visit the boat 2 or 3 times per week. I was actually thinking about leaving the cockpit drains isolated when I'm not sailing, as I have a full canvas cover, so there isn't much rain accumulation. And even if the cover failed, there wouldn't be enough rain to fill the cockpit in a day or two (Seattle area rains often, but not too hard).

As for bilge pump discharge, those would always be open, so having a plug handy is probably a more reasonable approach.

Faster 10-31-2012 07:15 PM

Re: Drains, valves, and seacocks: weighing the alternatives
If you do decide to add the ball valves, be advised that most valves will be NPT thread (ie tapered) and the through hull threads are not. What that means is that when you install the valves on the through hull threads you'll only get maybe 1 1/2 threads engaged before it tightens up.. not very secure. Check Mainesail's 'how-to' site for the RIGHT way to do this.

Replacing Thru-Hulls and Seacocks Photo Gallery by Compass Marine at

Brent Swain 10-31-2012 07:39 PM

Re: Drains, valves, and seacocks: weighing the alternatives
I use the type 316 stainless ball valves from the pulp mills, found in scrapyards for $1.50 a pound. They have given me no problems in 40 years. For thru hulls, I weld in type 316 stainless pipe nipples, also from scrapyards for $1.50 a pound. A composting head also eliminates a couple of thru hulls.
For my steel hulls, I use keel cooling and dry exhaust, eliminating a couple more thru hulls.

Rusty123 10-31-2012 10:49 PM

Re: Drains, valves, and seacocks: weighing the alternatives
After further investigation, I'm not certain that my existing through-hulls are actually Marelon. They look more like regular nylon. Which pushes me towards replacing them with new Marelon through-hulls and seacocks (at least for the below waterline cockpit drains) at the next haul out. In the meantime, I'll just replace the hoses -- the existing ones just look like an accident waiting to happen.

Watercolor 11-28-2012 10:59 PM

Re: Drains, valves, and seacocks: weighing the alternatives
Rusty, did you come to any resolution to your problem.

Rusty123 11-29-2012 01:03 AM

Re: Drains, valves, and seacocks: weighing the alternatives
I replaced the hoses with some heavy duty PVC/Vinyl sanitary hoses (Trident XHD). At my next haulout, I'll install new through hulls and seacocks (probably marelon).

ambianceack 12-01-2012 08:43 AM

Re: Drains, valves, and seacocks: weighing the alternatives
I actually need to do a similar repair. The two seacocks that drain the cockpit are not operating and I need to replace hoses. I was thinking about not replacing the seacocks since they do not leak and are in the drain position. Just curious, why are you planning to replace the seacocks? I am not sure if they are needed?

Rusty123 12-01-2012 10:38 AM

Re: Drains, valves, and seacocks: weighing the alternatives
Cockpit drains are a big hole in the hull. Seacocks give you a way to close the hole in an emergency. That's what it boils down to for me.

All times are GMT -4. The time now is 04:22 PM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
(c) LLC 2000-2012

For the best viewing experience please update your browser to Google Chrome