Stop cocks - to close or not ?

[25931]

Is there any good reason to interfere with an open cock ?
I ask because I've always been in the habit of leaving them open and the other day a chap who was interested in buying closed the heads outlet and then opened - later I discovered that it was dripping and continued to drip when closed again.

 

[G12]

So you let someone else interfere with your cock and now its dripping? Hmm....

So, more seriously, you need to exercise them - you've found one reason for yourself and another one is that you know if they've seized or not. Imagine needing the close a through hull and finding it seized solid.

EDIT: and you should close them when leaving the boat unattended...... things do break whilst owners are away sometimes with nasty consequences.

 

[VO5]

Yes, to open and close cocks periodically is a prudent practice many yachtsmen ignore. They should be opened and closed say once a fortnight or once a month at least to make sure they are functioning properly.
If left open for a very long time they are apt to seize.

 

[Dockhead]

There exist a variety of opinions about this.

I, for one, always close all my sea cocks whenever I am off the boat for overnight or longer.

One advantage of this approach is that working them often keeps your sea cocks from seizing -- a huge problem for people who never shut them off.

Obviously it also reduces the risk of your boat sinking at her mooring while you're not around, the main reason I close mine.

This begs the question -- off topic -- of whether your boat is less likely to sink from a split hose if you are ON the boat. It reminds me that I really need to install that bilge alarm without further delay.

 

[Deleted member 36384]

This old chestnut! I close all of mine when I leave the boat, I close the heads and sinks as they are near the water line when healing over, I don't close the seawater inlet to the engine when sailing as there is a very high anti syphon loop, on other boats I have had to.

This winter I found the seacocks for the aft heads outlet very stiff through lack of use. So if leaving them open its best to operate them a few times during the season.

If the hoses are in good condition, securely fastened, and the end point (sink or toilet for example) is not near sea level then why not leave them open, nothing is going to fail? However, do you know what material the seacocks are made from? The recent bad press about unsuitable seacocks suggests that the corrosion can be so severe that failure is likely. At least by opening and closing them one gets to visually inspect them regularly.

 

[johnlilley]

Close them all when off the boat for more than a day or two, but leave the cockpit drains open as the risk of heavy rain sinking a small boat by the stern is much higher than the risk of sound seacocks & pipework failing. Note the SOUND adjective though!

When ashore in winter leave all open so that water does not split the valve, it can & does happen quite often, but not seen until the boat goes back in the water.

Test gate valves by turning fully off tight & fully open tight. Really poor valves will shear the corroded threads on the operating spindle at heavy loads (tight open, tight closed) & note the amount of free movement on the handle when reversing from tight open or tight closed before the gate starts to lift. The more free movement the more the square cut spindle threads have worn or corroded to a point where the handle has nearly half a turn of free movement & could be near failure. A new gate valve has no more than about 10 degrees of free movement if that.
Check out survey photos on web site.

John Lilley

 

[Heckler]

Is there any good reason to interfere with an open cock ?
I ask because I've always been in the habit of leaving them open and the other day a chap who was interested in buying closed the heads outlet and then opened - later I discovered that it was dripping and continued to drip when closed again.

I always close them when not on the boat and when sailing, having said that I have now invested in some twist and lock Jabsco things for the heads. I can now leave the nearest one to the cockpit open whilst sailing. Less faff if its lumpy.
Stu

 

[stevebrassett]

I always close mine when leaving the boat simply because it is an extra line of defence. The seacock has to fail and the hose has to fail (yes I realise the seacock could fail catastrophically all by itself).

 

[ghostlymoron]

Test gate valves by turning fully off tight & fully open tight. Really poor valves will shear the corroded threads on the operating spindle at heavy loads (tight open, tight closed) & note the amount of free movement on the handle when reversing from tight open or tight closed before the gate starts to lift.

Better still replace all gate valves with good quality ball valves. Much safer IMO but ball valve spindles can also fail leaving the handle to turn and giving the impression that they are operating but the ball staying open/closed or anywhere in between.

 

[Appledore]

Test gate valves by turning fully off tight & fully open tight. Really poor valves will shear the corroded threads on the operating spindle at heavy loads (tight open, tight closed) & note the amount of free movement on the handle when reversing from tight open or tight closed before the gate starts to lift.

I always keep the valves on my boat closed, except for the engine cooling water valve when using engine, otherwise that's closed too.

Recently I had noticed some droplets of rusty water on the galvanised elbow to the heads outlet gatevalve (1.250 inch bore). Cutting a long episode short, when I removed said elbow it was rusted trough from the inside. The rusty remains had mainly settled in the gate valve itself, and therefore there was no way the valve was closing, even though I was turning it off tightly, or so I thought. Valve has now been dismantled, cleaned and re-assembled (it is gunmetal or bronze), and the elbow replaced. But I wonder how long it may have been before the elbow sprung an actual leak, and my boat would therefore have sunk on its mooring?

So, gentlemen, do not assume that when closing your gate valves, they are actually watertight

 

[Sandyman]

Part of monthly maintenance routine.
Open & close each valve / sea-cock for or five times and a quick spray of WD40.

 

[Kelpie]

Always off when not in use, except the engine inlet which is left on whilst we are underway or at anchor.

When I was replacing all the through-hulls and valves (between tides, cos I like a challenge) I had taken the toilet off for better access and was alarmed to find water streaming in through the supposedly closed heads outlet. The gate valve had failed and a fairly steady trickle was getting past. I think that for the preceding years/months it was only the integrity of the toilet and its hoses which had stopped the boat from sinking.

 

[jwilson]

There exist a variety of opinions about this.

I, for one, always close all my sea cocks whenever I am off the boat for overnight or longer.

One advantage of this approach is that working them often keeps your sea cocks from seizing -- a huge problem for people who never shut them off.

Obviously it also reduces the risk of your boat sinking at her mooring while you're not around, the main reason I close mine.

This begs the question -- off topic -- of whether your boat is less likely to sink from a split hose if you are ON the boat. It reminds me that I really need to install that bilge alarm without further delay.

On many older-style GRP boats you virtually HAVE to leave the two cockpit drain seacocks open all the time when leaving the boat, otherwise the cockpit will fill with rainwater to the point where water gets below via cockpit lockers and/or the main companionway. The only way round that is a really well-fitting non-sagging cockpit cover, which is a PITA to fit and remove every time, as well as needing lots of little lacing hooks or similar fixings fitted.

It always seemed to me when I had that type of boat that I was not really in much greater danger fom leaving sink, heads, and engine seacocks open as well. Though I fully agree that all should be operable if needed, I usually left them all open unless going away from the boat for a really extended period.

Now I have a modern open-transom-cockpit I do usually turn off all internal seacocks, but do not worry that much if I forget to for a week.

Bilge alarms?? - if you're on board you'll probably notice as the water gets over the top of your boots, and if you're not aboard all the alarm will do is flatten your battery a bit more than the auto pump already has done, before the boat sinks.

 

[Dockhead]

Bilge alarms?? - if you're on board you'll probably notice as the water gets over the top of your boots, and if you're not aboard all the alarm will do is flatten your battery a bit more than the auto pump already has done, before the boat sinks.

You won't notice if you're sailing and everyone is in the cockpit.

And even if someone is below, if the water is already over the sole plates, you are in a heap of trouble.

A bilge alarm might give you a chance to find and stop the leak before the whole bilge is awash and the boat is already sinking.

If you're not on board and have a leak which the pumps can't keep up with, then you don't care how fast the batteries are drained anyway. God forbid. If the pumps can keep up, then the alarm won't sound, and all you can do is hope someone sees the stream of water coming out.

 

[Heckler]

Part of monthly maintenance routine.
Open & close each valve / sea-cock for or five times and a quick spray of WD40.

On the main outlet from the heads, I close it half way (its a ball valve) then i put a good glug of cooking oil in the heads and pump it out, this "oils" half of the ball, and when you shut it it wipes oil on to the seals to lubricate them.
Stu

 

[Fantasie 19]

Yes, to open and close cocks periodically is a prudent practice many yachtsmen ignore. They should be opened and closed say once a fortnight or once a month at least to make sure they are functioning properly.
If left open for a very long time they are apt to seize.

Same goes for the cold water stopcock in the house... don't ask me how I know...

 

[johnalison]

Thoughtless design in an otherwise clever boat has left me with some seacocks that are very hard to get at, including the heads inlet, only accessable through the aft cabin. There are thus some cocks that we don't always close. I tend to not worry about it and exercise the seacocks fairly regularly when I can.

Someone once pointed out to me that it's the seacocks that are left closed that deteriorate faster, since corrosion or concretion on the exposed surface can eventually damage the plastic or cause the cock to stiffen.

 

[25931]

You won't notice if you're sailing and everyone is in the cockpit.

And even if someone is below, if the water is already over the sole plates, you are in a heap of trouble.

A bilge alarm might give you a chance to find and stop the leak before the whole bilge is awash and the boat is already sinking.

If you're not on board and have a leak which the pumps can't keep up with, then you don't care how fast the batteries are drained anyway. God forbid. If the pumps can keep up, then the alarm won't sound, and all you can do is hope someone sees the stream of water coming out.

If you have leak that the pumps can keep up with until the batteries run flat and if you return before the boat sinks you might like to have enough battery left for the pumps - tricky.

 

[blackbeard]

One of the boats in our clubs took on a quite lot of water a while ago. Fortunately someone noticed it was floating bit low, but this isn't obvious until there is quite a lot of water inside.
Problem was, it had been left for some time with the engine cooling water seacock open. Apparently there was a pinhole leak in a hose pipe.

 

[KellysEye]

>I always close mine when leaving the boat simply because it is an extra line of defence. The seacock has to fail and the hose has to fail (yes I realise the seacock could fail catastrophically all by itself).

Yes agree, always close them when off the boat.