Seacocks - When to Close Them

How many of you that have boats moored at marinas close the seacocks on your boat before you leave the boat? Are there some you leave open?

Q1. I close all.
Q2. See 1 above.
It`s said sailboats close them, power boats don`t. I closed them on sailboats, and close them on powerboats. Something can fail upstream of the open seacock.

Dan,
I close all of them if I'm not going to be on the boat for awhile, i.e., a couple of weeks or more. Week to week when we're going out frequently I don't close them.

We keep all 12 of our seacocks closed at all times except the two for the main engines. The others we open only if we're going to be using them on a trip.

Marin said:

We keep all 12 of our seacocks closed at all times except the two for the main engines. The others we open only if we're going to be using them on a trip.

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Marin, Am I correct in assuming you close the two engine seacocks also when you leave the boat?

GFC said:

Dan,
I close all of them if I'm not going to be on the boat for awhile, i.e., a couple of weeks or more. Week to week when we're going out frequently I don't close them.

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Mike, I'm assuming yours are all closed now?

Budds Outlet said:

Marin, Am I correct in assuming you close the two engine seacocks also when you leave the boat?

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No. We leave them open all the time in case someone has to move the boat in an emergency.

Mine are all closed. I have just three. The Perko (for the engine) is opened right after I check the oil before start-up.

Once a month I do exercise the handles to make sure they move easily.

Heck, even the pressure water is off unless I'm taking a shower or washing dishes. I have a hand pump at the galley to get water out of the tank without the pump.

Thanks for the clarification Marin. I am working a deal on a boat and the port engine heat exchanger has to be changed out. It needs to be hauled to do the repair as that engine's seacock is frozen open. I guess it makes sense if it is never closed. It seems that there should be a routine of exercising the seacocks so that if they are needed they will work.

Thanks Janice. I like the idea of a monthly exercise of the seacocks. If that regime had been followed on this boat it would not need to be hauled to do the repair.

We operate the seacocks on the boat several times a year, although some get used every time we go out. Any that are getting overly stiff get adjusted and greased.

The first thing I think I need to do is make an inventory of all the thru hulls. I'm thinking that those above the waterline will probably not have seacocks but that is an unknown to me. My only experience with seacock was with my Sea Ray that had two above the waterline thru hulls for the sinks and two below waterline for the head, one supply and one discharge. I kept the discharge closed all the time as I cruised in Puget Sound mostly. I would open the supply for the head when we were onboard. there were no seacocks on the sink drain thru hulls.

Budds Outlet said:

Thanks Janice. I like the idea of a monthly exercise of the seacocks. If that regime had been followed on this boat it would not need to be hauled to do the repair.

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Excellent point. I always used to close all seacocks to below waterline thru-hulls - there are only 4 to close anyway on our boat - however, just last december the main engine seacock was replaced as part and parcel of a replacement of the sea-strainer as well. Unfortunately this new super-dooper seacock/strainer combo has a detent on the handle that one has to slide up to move. Previously, to avoid having to remove flooring and huddle up near a hot engine after an outing, I had a long handle extension with a knob on the end I could open and close that seacock remotely from the front hatch in the galley floor, easily removed, and away from the heat of the motor. Now I can't, and I have to remove the saloon floor and the engine room floor to reach the damn handle, so it stays open. See what I mean and why I don't close it each time any more..?



Recently I went down and worked it and found it really stiff, so made the mental note to work it more often, or it might seize up - it was close.

All my sea-cocks are closed when the boat is unoccupied except the air conditioning because it is usually left on in the humidity mode. There is of course a real risk that plumbing in the AC line could break and sink the boat, but in south FL the AC needs to be left on. I suppose I reconcile the open AC valve in my mind by having insurance.

My only 2, one for the main, one for the genset/washdown are always open unless I have a specific need to close them such as winterizing the systems while still in the water.
I even leave them open when I remove the screens for cleaning.

If leaving for a few days I shut off the shore water supply and that's it. I exercise the valves and check connections/hoses monthly. If I was to leave for more than a week, I would probably close them just for peace of mind.

> It needs to be hauled to do the repair as that engine's seacock is frozen open<

You will notice a 1/8 pipe plug on either side of the seacock.

Remove it and install a 1/8 pipe Zerk fitting .

A light grease or grease mixed with ATF can be pumped in.

If it is a better quality seacock, loosening the nut on the shaft (there should be 2, a nut and lock nut) after a bit after spraying with JB Blaster a light tap on the shaft end may solve the ha$$le with out a haul.

Good luck.

Remember to lube/operate ALL the sea cocks if you get pulled.

FF said:

>
Remember to lube/operate ALL the sea cocks if you get pulled.

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How do you recommend lubing a sea cock with the boat hauled?

timjet said:

How do you recommend lubing a sea cock with the boat hauled?

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A friend sent this to me recently. I haven't tried it yet though.

Re: Servicing Seacocks

Here is what I do with the boat on the hard to lube the stainless ball type seacocks without having to dissemble them:

rotate the seacock handles so that the ball inside is halfway open. Put a big dab of PTFE or similar grease on the tip of a narrow dowel. Insert the dowel into the seacock from the underside carefully going all the way thru the ball. (helps to practice this without the grease on the dowel just to get the feel of going all the way thru the ball). Now scrape dowel downward on the upper outside of the ball to get the grease on top of it. Go inside boat and rotate handles to spread the grease. Then close all seacocks completely. Put some more grease on the tip of the dowel and put it into the seacock thru-hull to grease the undersides of the ball. Rotate handles again. Works for me, hope it does for you, too.

Try this

Budds Outlet said:

Thanks for the clarification Marin. I am working a deal on a boat and the port engine heat exchanger has to be changed out. It needs to be hauled to do the repair as that engine's seacock is frozen open. I guess it makes sense if it is never closed. It seems that there should be a routine of exercising the seacocks so that if they are needed they will work.

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Try loosening the nut, tap gently on the end of the nut, squirt PB Blaster liberally on the thru hull shaft and nut. Wait a day and try to open the valve. If your lucky this may work. If your doing a survey, you'll be pulling the boat anyway.

Thanks for all the input. I will definitely institute a regime of exercising the seacocks on a regular basis.


The haul out will happen anyway as I am having the hull surveyed. I'm paying for the haul and launch and the seller is paying for the lay days while the repair is being completed. I am going to have all the seacocks checked as part of the survey so any others that don't function will be repaired at the same time.

We've been through this several times and the actual answer to this is to close all seacocks whenever you're engine is'nt running and you don't want your boat to sink.

Dan, yes, all of mine are now closed in prep for an extended vacation. One word of caution--when I do that I hang red/black "DO NOT USE" tags on the engine and generator start switches as a reminder to me that they're closed.

Someone above mentioned adding a grease fitting in place of the drain nut. I did that a couple of years ago and keep a grease gun in the engine room. About once a year (usually in the spring when I'm doing my spring maintenance) I'll give them a shot of grease and work them a few times.

I don't close the seacock for the automatic bilge pump. I don't open the seacock for the blackwater tank.

I like the signs idea. Maybe an explanation on the sign as to the location of the respective seacocks would be in order if someone unfamiliar with the boat needed to move it.

Or just keep your seacocks and hoses in top condition, only have a minimum of them and keep strainers and pumps so near the waterline a leak is a trickle and not a flood.

Then even the wimpiest of bilge pumps will keep up...but have 3-4 robust ones and sleep well..whether your seacocks are left open or closed.

Dan, they're pretty standard tags. I couldn't find one to post on here, but here's a link to the type I use on Amazon.

http://www.amazon.com/Accuform-Signs-MLT406CTP-Thickness-PF-Cardstock/dp/B009D4HWUA/ref=sr_1_1?ie=UTF8&qid=1419285106&sr=8-1&keywords=danger+tags

When I close the seacocks, the first thing I do is hang the tags on the engine start switches on the helm, and on the generator start switch on the power panel.

Having them in the engine room wouldn't do any good because if someone didn't know the seacocks were closed they wouldn't likely go to the engine room before starting the engines or genny.

I put a zip tie through the hole and just hang 'em on the start switches.

Nice Mike. Thanks for the link. I think I would follow up with naming the closed seacock on the tag. That way there would be no confusion if you only had one closed for service and it somehow got knocked off the switch.

Good topic and it makes me realize I should start closing them all when leaving the boat for more than one week (which I never did in all my previous boats with no issue). I have 8 in total (bummer...)
* 2 for main engine, and 1 for genset
* 1 for A/C, and 1 for sewage tank overboard (Purasan system)
* 3 for my heads
I think that's it...

I leave mine open but exercise it every trip. My logic is even with a check list "stuff happens". I'd rather not forget to turn it on and risk engine damage or somebody else damage it if the need to move it in my absence. As Tim said earlier having insurance is perhaps how I rationalize it. That and adequate bilge pump capacity.