Cockpit Drains

[KeelHaulin]

I have a question regarding the configuration of cockpit drains. I have 6 drains (two deck drains, 4 cockpit) that are routed to 2 2" thru hulls beneath the forward cockpit drains. The problem I see is that these drains will allow rainwater to exit while at the dock but the thru-hull valves must be open for this to happen. If I close the valves the cockpit will flood and overflow into the cabin through the companionway.

I'd rather not leave these thru hulls open while away from the boat because they are below the waterline and there are multiple hose connections on those lines between the drain and the valve. So I was thinking that it would be a good idea to close the thru-hulls and then open a diverter valve that allows the rainwater to go into the bilge; which would then be pumped out by the bilge pump (or go to a dedicated sump system).

Thoughts?

[sailingdog]

It would probably be wise to have at least two of the drains connected to above waterline through-hulls.

The problem with having these go to a sump or into the bilge is that if the bilge pump fails, you will pretty much guarantee your boat sinking in a heavy rainstorm. In fact, having the seacocks open in the current setup is probably safer, provided the hoses are inspected regularly and double clamped, than changing the setup.

BTW, I would separate the deck drains from the cockpit drains, since the deck drains add a lot of surface area to collect water in a rainstorm.

[KeelHaulin]

That might be a possibility; but it's possible that the cockpit floor is too close to the waterline height; not sure. My boat has a low freeboard and a deep cockpit. I'll need to measure the depth of the water inside the drain hoses to determine how low the thru-hull will need to be; and look at the line drawings. On the starboard side there is a quarterberth so plumbing over to the hull on the starboard side would be difficult if not impossible. On the port side I could probably plumb a drain so that all 4 of the cockpit drains would exit when the seacocks are closed. Or, possibly another thru-hull fitting beneath the transom? (bilge pumps and engine exhaust are already located there)

I agree that the deck drains probably add a lot of water to the drain system. I have seen on one other boat that these drains were epoxy back filled so that the drain is no longer active. They don't clear all of the standing water anyway and with aluminum toerail only a small puddle collects on each side. I will block those holes and check to see how much more standing water there will be first.

Thanks for your helpful comments...

[sailingdog]

It really doesn't make sense to have all four of the cockpit drains drain via a single through-hull, since that would seriously restrict the drain rate. It might make more sense to have the two port side ones drain via above the waterline through-hulls, and leave the two starboard ones plumbed the way they are. Since you're not really at risk of getting pooped when at the dock or anchor, this shouldn't increase your risk of sinking from the cockpit filling to any degree.

If you're planning on doing any long distance cruising in your current boat, plumbing a diverter valve into the line that drains the deck drains is a good way to setup a rain water collection system.

Originally Posted by KeelHaulin

That might be a possibility; but it's possible that the cockpit floor is too close to the waterline height; not sure. My boat has a low freeboard and a deep cockpit. I'll need to measure the depth of the water inside the drain hoses to determine how low the thru-hull will need to be; and look at the line drawings. On the starboard side there is a quarterberth so plumbing over to the hull on the starboard side would be difficult if not impossible. On the port side I could probably plumb a drain so that all 4 of the cockpit drains would exit when the seacocks are closed. Or, possibly another thru-hull fitting beneath the transom? (bilge pumps and engine exhaust are already located there)

I agree that the deck drains probably add a lot of water to the drain system. I have seen on one other boat that these drains were epoxy back filled so that the drain is no longer active. They don't clear all of the standing water anyway and with aluminum toerail only a small puddle collects on each side. I will block those holes and check to see how much more standing water there will be first.

Thanks for your helpful comments...

[sailboy21]

If your seacocks are in good repair and you use double high quality hose clamps there shouldn't be any issue leaving them open. If you are really paranoid consider closing them halfway or more. Pour a bucket of water in the cockpit to make sure they still drain, but at a rate you think the bilge pump could handle if a leak inside were to develop. Just make sure the cockpit is clean so nothing could clog a partially close valve.