3-way DZR / bronze ball valve?

[prv]

Hi,

I'm going to be removing and overhauling my engine this winter, and I want to take the opportunity to add some "unstoppability" features (dual changeover fuel filters being the classic example).

One of the things I'd like to do is make it possible to "rod out" the intake seacock in case anything gets stuck in it. The boat will be on a mud berth, which seems to provide a certain potential for debris, plus there's always the rogue carrier bag to watch out for. Fortunately, the arrangement of the boat is such that the seacock is in a relatively spacious location under the cockpit, with an access hatch in the sole directly above it. What I was thinking of doing was replacing the current gate valve with a three-port ball valve. One arm of the T would screw onto the skin fitting, while the engine intake would be on the side arm. The remaining arm, facing upwards, would have an 18" length of fairly lightweight transparent tubing.

Normally, the valve would be set to connect the intake arm to the engine. In the event of blockage, though, the transparent tube would be brought up through the hatch, bringing it above the waterline. The valve would then be turned (after undoing some kind of security device to prevent accidental switching to this mode) to connect the transparent tube in-line with the skin fitting. A straight rod clipped nearby for the purpose could then be shoved down the tube and out through the skin fitting. I might well also add a hose barb and screwed blanking fitting to the open end of the tube, as a second safety cutout.

The only flaw in this plan (unless you guys care to suggest others ) is that I cannot find anyone selling three-way ball valves in a material that I would want to use on a skin fitting. Any pointers?

Pete

 

[rogerthebodger]

I something simular but I fitted a tee to the inlet skin fitting with a single ball valve on the sid arm of the tee to act as the sea cock. I did not fit a valve to the other leg just fitted a plug but a valve with plug could be fitted if need be.

I in fact have twin sea cocks of the above type going into a manifold with twin strainers so if I get a blockage in either the inlet or the strainer I can simply open the unused sea cock and close the blocked until I can clean the blockage.

See below shown before fitting

 

[Tranona]

This is all too complicated. Use a normal ball valve (not a gate valve as you seem to have now) and use a Vetus water filter immediately above the inlet with the bowl above the water line. The filter will reduce the chance of blockages through weed etc that will be caught by the strainer and if the blockage is at the intake you can easily pass a rod or direct air say from a dinghy pump down the inlet hose to clear it. I have this arrangement on my boat, although have yet to need it in anger.

 

[vyv_cox]

This is all too complicated. Use a normal ball valve (not a gate valve as you seem to have now) and use a Vetus water filter immediately above the inlet with the bowl above the water line. The filter will reduce the chance of blockages through weed etc that will be caught by the strainer and if the blockage is at the intake you can easily pass a rod or direct air say from a dinghy pump down the inlet hose to clear it. I have this arrangement on my boat, although have yet to need it in anger.

I agree. The best way to reduce the possibility of blockage is to increase the bore of the system. My 3/8 engine coolant blockages disappeared when I went to 1/2 inch. Go up one size if there is a known problem, change skin fitting, valve and tubing and as Tranona says, use a Vetus filter.

Transiting the Canal du Midi required very frequent clearing of the old inlet valve. Taking the hose off and rodding through was routine after a while, all done in less than a minute. Hardly worth the expenditure on a 3-way valve.

 

[Tranona]

That is interesting about bore sizes. I currently have a 1/2 inch intake for the Yanmar 1GM. Just installing a new Nanni 14 and have to change to a 20 mm which means a new filter and a change of location as the engine is wider at the point where the filter is currently. Exhaust and anti syphon also needs changing as exhaust is the other side. However footprint is basically the same so small mods should make it an easy swap.

 

[prv]

This is all too complicated. Use a normal ball valve (not a gate valve as you seem to have now) and use a Vetus water filter immediately above the inlet with the bowl above the water line. The filter will reduce the chance of blockages through weed etc that will be caught by the strainer and if the blockage is at the intake you can easily pass a rod or direct air say from a dinghy pump down the inlet hose to clear it.

I would of course fit a strainer as well, but something like a carrier bag would just get wedged in the inlet without getting as far as the strainer. I like your idea of having the strainer directly above the seacock so that after opening the strainer (which would probably be the first step) you can easily move on to rodding down the inlet. That's definitely the best solution. Unfortunately, though, my strainer and everything is all going to be below the waterline under the cockpit. The boat has a long keel and the engine mounted low down - there's not much space in the engine bay that's above the waterline. Hence my plan for a flexible tube that could come up through the hatch in the cockpit sole to give me above-waterline rodding access when necessary.

Replacing the gate valves with ball valves throughout is a given.

Cheers,

Pete

 

[prv]

I something simular but I fitted a tee to the inlet skin fitting with a single ball valve on the sid arm of the tee to act as the sea cock. I did not fit a valve to the other leg just fitted a plug but a valve with plug could be fitted if need be.

This seems like a sensible way to go. I realised after posting that the available ball configurations (L or T) meant that a three-way valve wouldn't be entirely satisfactory anyway.

I in fact have twin sea cocks of the above type going into a manifold with twin strainers so if I get a blockage in either the inlet or the strainer I can simply open the unused sea cock and close the blocked until I can clean the blockage.

That's good bombproofing, but I don't think I have the space. I'm hoping to do something similar with fuel filters though - need to really get my head into the engine bay and figure out the possibilities.

Cheers,

Pete

 

[alahol2]

Fit one of these above your seacock and you will be able to rod straight through.

 

[JohnTH]

What is wrong with a gate valve on the skin fitting? A “T” after that and another gate valve on top, above the waterline. this works well enough and there is a clear hole to rod out rubbish ! The top gate valve is to prevent water splashing from an otherwise open pipe.

Even better, but more expensive, is to have the filter unit as per the the above picture.

73s de
Johnth

 

[Tranona]

What is wrong with a gate valve on the skin fitting? A “T” after that and another gate valve on top, above the waterline. this works well enough and there is a clear hole to rod out rubbish ! The top gate valve is to prevent water splashing from an otherwise open pipe.

Even better, but more expensive, is to have the filter unit as per the the above picture.

73s de
Johnth

A Gate valve is not appropriate for underwater - you need a ball valve.

The strainer shown in the picture is OK but it does not usually come above the waterline so when you take the cap off to rod through and clear the blockage water comes rushing through! Not a good idea I suggest!

The use of a Vetus type trap above the waterline is the way to go.

 

[alahol2]

The strainer shown in the picture is OK but it does not usually come above the waterline so when you take the cap off to rod through and clear the blockage water comes rushing through! Not a good idea I suggest!

The water doesn't actually rush through, it 'glugs'. At least you know it is clear and it takes only a second to close the ball valve. I would guess I get about a half pint into the boat when I do it now.

First time I did it I used a screwdriver to rod through. I then dropped the screwdriver, the handle of which fitted neatly inside the strainer. I now had water coming into the boat, no way to shut the seacock and no easy way to grab the screwdriver. Had to swiftly put the lid on the strainer while I worked out my options.
I now have a special screwdriver with a big handle that won't fit inside.