Blakes sea-cock - how tight

[IanC]

I've followed all the postings about blakes sea-cocks(the cone shaped ones). I've just serviced mine - ground it and greased it. How tight do I do the two bolts on the top - should it move relatively easily - or should I have to give it a load of grief to move it?

Also I can I leave it open when I'm on the boat - I don't need to shut it every time after I go to the loo do I?

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[tillergirl]

I have mine so that I can turn them without force but not so loose that they will move by vibration. How to describe this in words ain't easy. I can't turn them with one finger but I can with two fingers and a thumb! Does that make sense? I keep mine well greased with Blake's Seacock grease and have never seen any sign of seepage at all. As for leaving them on you need to ensure you don't have a syphon going on. I tend to leave the inlet open all the time but close the outlet after use but I suspect this defies logic. I also have double clipped all pipe connections and check their soundness at the beginning and mide season.

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[neil_s]

I can't turn the handles on mine if the cap screws are done up more than finger tight! I also leave the sea cocks open while aboard - but you need to check your own installation to make sure that the pipes are sound and there is no risk of sea water syphoning back into the bowl after use.

I'm not that fond of pumping my loo out into the sea, anymore, and am looking at fitting some sort of holding tank. This will also remove the need for seacocks!

See you sailing! Neil

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[johnwest]

I would agree with tillergirl on the feeling of the seacock. Mine are about the same
stiffness. I leave mine open all the time , except when I leave the boat for an extended period. When pumping out make sure that the last two or three stokes are blowing air bubbles up the pipe which should prevent any syphon action.

j

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[snowleopard]

holding tanks & seacocks

unless you want to be totally reliant on pump-out stations it will be necessary to provide for pumping out at sea. holding tank discharge will need to be below waterline so will still need a seacock.

we use a big bilge pump with T-valve to serve both bilges and pump-out. it discharges through a single 1.5" seacock.

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[Gunfleet]

<<I leave mine open all the time , except when I leave the boat for an extended period. >>
John, this is asking for trouble. I have never had any trouble with the seacocks on my boat then - out of the blue - it started siphoning during one night. Luckily I was aboard and it has a deep bilge. I awoke when the floor was awash. If I'd locked up and gone down the pub for a couple of hours... well, you can imagine.

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[roger]

Make sure the ring holding the cone down cannot rock - thats an easy test.
Make sure the bolts are locked tight with the nuts that should be on the bolts. Access to these nuts is often difficult. I suggest you make sure you have easy access by modifying the boat or you'll be tempted to skimp on maintenance.
On passage I've often found the head filling up. Its much safer to turn the cocks off unless you are actually pumping out the head. You will get some extra safety if you have the recommended pipe loops and air bleeds.
I like my seacocks to be easy to move - they are much more likely to get stiffer rather than easire.

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[jcr]

The two bolts should be no more than finger tight. It is important that the retaining plate is parallel with the top of the cone. To ensure this, screw the bolts down alternately, a few threads at a time, ensuring that each bolt is screwed down by the same number of threads. Check that the cone can be turned easily. Then tighten the bottom lock nuts and check the cone again. You may find that you have to turn back the bolts (perhaps half a thread) so that, when the lock nuts are again tightened, the cone can still be turned easily without leaking.

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