Seacocks

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angelsson

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Have two seacocks in my engine compartment Nic 38, which are gate type and just keep turning and are jammed in the open position. They are not part of the skin fitting but are screwed onto it.
I want to replace them with good quality ball valves.

Would anyone help me with what size they are and which ball valves would be best to replace them with, and a source if possible.

I wish to purchase the new new valves in the UK and take them out to the boat in Sardinia, rather than remove them and hope I can find the right type and size there.

Many thanks
 
Sorry can't help with the size on a Nic, but surely you can see them? If the thread diameter is about 3/4inch it will be called a 1/2inch seacock, and similar for larger sizes.

I have used the zinc-plated brass types (ball valves) with no problem, except for one which seized and handle (mild steel) broke. I replaced it two weeks ago, and my biggest worry was if the seacock would come off without disturbing the skin fitting. Fortunately it did. As the price difference was minimal, I replaced it with a (claimed) bronze one anyway ... though handle was still mild-steel. Examining the old ball-valve (10yrs+) there is no sign of corrosion. (all my seacocks are electrically isolated).


Vic
 
Ball valves and gate valves are both plumbing fittings. Assuming the valve fits to a male skin fitting(most likely) 3 sizes are the most common 15mm,22mm 28mm. Giving the size of the engine I would assume it is not 15mm,and,if it is a water inlet to the engine it is not likely to be 28mm. So that leaves 22mm i.e. a 22mm female ball valve and take a 15mm reducing set just in case. Available at plumbers merchants or chandlers.
 
Substitute 3/4" for 22mm and 3/4" to 1/2" bushes for reducing sets. The reason for this is that your skin fitting will be imperial thread not metric pipe.
 
Plumbing Fittings

...................................................................................

No NO No No

Use the right fitting.........They will be bronze marine fittings and not MM but Bsp thread sizes IE 1/2 and 3/4 BSP

Use Homebase and B and Q fittings at your peril as these are not bronze and will dezinctify quickly unless you are only in fresh water.
 
They are really very easy to replace - I changed mine and obtained new ones from ASAP supplies by mail order.

The outlet from the sink was

3/4 inch BSP ball valve DZR

and the engine inlet was the 1/2 inch version.

DZR is the reccommended material.

To be honest iof you aren't sure of the size then they are cheap enough to buy a few different ones and then return the ones you don't need later (less postage and 10%), but I think you will find that 3/4 inch is fairly standard.

I used the old "hosetail" fitting from the inboard side of the gate valve on the new valve, though it required a large vice to separate them.

If you haven't got the ASAP catalogue get it - excellent referenece book when refitting anything engine, plumbing, electrical on boats and they will shipm anywhere in the world albeit at a price.

regards
 
You will find, (with the possible exception of Russia), that ‘world over’ ALL pipe dimensions and thread forms are BSP (that is British Standard Pipe) measured in ‘inches’. They are used and can be obtained anywhere in east and Western Europe, the Far East Australasia etc. I’ve no knowledge of Sardinia but suspect that the same is true there.

Thus 15mm ‘outside diameter’ copper pipe is ½ inch bore (12.7mm + 1mm wall thickness) likewise 22mm is ¾ inch bore (19.7 + 1mm wall thickness) [BTW there are two ‘walls’ either side of the ‘hole’ wherein the liquid flows] 28mm is therefore 1 inch and probably about as big as most ‘skin fittings go; apart from the ‘loo’ outlet, that is.

If possible whilst you are at it, run a longer pipe from the skin fitting, to a point ABOVE the waterline and there put the valve (as said above, preferably good quality bronze rather than B&Q’s domestic quality brass). You can then maintain/grease/replace the valve when needed without sinking the boat.

Cheers CRB
 
[ QUOTE ]
If possible whilst you are at it, run a longer pipe from the skin fitting, to a point ABOVE the waterline and there put the valve. You can then maintain/grease/replace the valve when needed without sinking the boat. Cheers CRB

[/ QUOTE ]
Surely the idea of the valve is if any hose leaks then closing the valve stops you sinking. Since you might find the whole bilge filled with water and not be able to instantly identify were its coming from, closing all valves ought to bide you time. What happens if the hose from the skin fitting to your above water line valve leaks /forums/images/graemlins/confused.gif

Pete
 
Pete,

You are correct, I’m not advocating the use of ‘hose’ etc from the skin fitting, rather a ‘solid’ pipe you can rely on, firmly plumbed and secure that takes the level above that of the waterline such that any maintenance can be done easily.

In a steel boat for instance, skin fittings are pipes welded to/through the hull and usually taken up above the waterline for this very reason.
 
Many thanks to each one of you who generously took the time to reply to my query, which will be most valuable.
Good luch and best wishes
Mike
 
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