Blakes seacock strainer

[Ex-SolentBoy]

Blakes seacocks come with a strainer to go on the outside of the hull.

My simple understanding was that you used the strainer for inlets, but left it off for outlets. A recent incident has made me rethink this.

On passage this week a friend found his engine starting to overheat. Correctly identifying a blocked water intake he was able to tie up at a nearby town and investigate. A plastic bag had been sucked into his seawater intake through the strainer. Hard to believe but true. I guess the bag was rotting.

Anyway, they managed to clear it by a combination of diving and fiddling around in the boat. The boat of course was fitted with a proper strainer inside the hull as well.

The point was made that if there was no strainer on the outside of the hull and reliance was put on the internal strainer it would be easy to simply poke a stick from inside to out.

On the either hand, with no external strainer the flow into their would be greater with associated increased risk of sucking bags and other debris in, albeit to hopefully get caught by the internal strainer.

What do you think?

 

[rob2]

I just wondered which way round the strainer was fitted? The shell types are often fitted as a scopp facing forward, although I was once told that it should be reversed so that it deflects objects rubbing along the hull.

Agreed, the ordinary strainers prevent rodding through so if you're planning on removing it, make sure you have a simple procedure for doing it. Some people fit a stand pipe reaching above the waterline so that the rod can be shoved down. If, like on my boat, there just isn't room for that you may need to use a more flexible rod and undo the hose from the far end so that it can be raised above WL to achieve the same end.

Rob.

 

[vyv_cox]

When we transited the Canal du Midi we suffered endless blockages of the engine inlet seacock by dead leaves. I probably rodded through more than 20 times by closing the seacock, taking the top off the internal strainer, inserting a brass rod, then opening the seacock and pushing the rod down. This allowed a small amount of water into the boat, subsequently mopped out. Presumably the leaves might well have been drawn onto the surface of an external strainer, making them far more difficult to remove.

 

[pampas]

I just wondered which way round the strainer was fitted? The shell types are often fitted as a scopp facing forward,

Rob.

There are two types, 1. with no internal scoop, this must have the grids facing aft,

2, the internal scoop tpye MUST have the grids facing forward in order not to create a suction.
Trust this clarifies a bit.

 

[doug748]

I fitted a Blakes seacock on the engine intake, last winter. For the reasons you outline, I did not fit the hull strainer.

No problems so far, but you do have to think through what to do if there is a blockage between the inlet and the remote strainer. For example you could try blasting it back with a dinghy pump, use vyv cox's/Rob2's rodding methods or remove the whole pipe for attention.

 

[rogerthebodger]

When I built my current boat I fitted inlet strainers on the skin fitting, when I beached last month to get ready for summer I found then full of critters partially blocking the inlet with no real way to clean then out completely so I took an angle grinder to remove the grills to allow proper cleaning and anti fouling up inside the inlet pipe.

I can rod from the inside but without the external grill it will be much easer to clean then properly

I would never fit external inlet strainers again.

 

[ianat182]

Whilst not directly answering your question, I use a plastic covered curtain wire to travel the full length of the inlet pipe to the raw water filter fitted with a small cup hook to clear baby mussels etc, a form of preventative maintenance as far as I'm concerned on the weedy Hamble and Solent, and can be done comfortably with no delving; The dinghy inflator or the 12v tyre inflator I've also used to clear in the past,also for cockpit drains.


ianat182

 

[prv]

Many boats seem to only use Blakes seacocks for the heads, with skin fittings and ball valves elsewhere. This is what I have, so the question of an external grille doesn't arise.

In my case, the hose from the engine seacock needs to run off horizontally - that is, a 90º elbow fitting would normally be fitted on top of the valve. I instead fitted a T with the upwards-pointing arm blanked off. Next to it is stowed a portable standpipe and a plastic rod, so if I ever needed to unblock the outer opening I would close the valve, open the blanking plate, screw on the pipe, then open the valve and rod through.

Naturally, this preparation ensured that I've never needed to use it

Pete