leaking vented loop

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leaking vented loop

Postby daletournier » Sat Jul 18, 2015 10:48 pm

Hi, the Hoyt f32 has a mid mount engine that is quite deep in the boat and the anti siphon valve ( vented loop) under the galley bench isnt as high as I would like it. On a previous boat I have had this valve salt up (not opening) resulting in a hydro locked engine ( fortunately no harm done). Im quite paranoid due to that experience and religiously reach under the sink and manually press that little valve down straight after turning the engine off. Twice ive felt my manual activation disrupt a siphon taking place. The problem I have is quite often this valve dribbles a little, not sealing well, this is quite common with vented loops, obviously this is something I dont want as it results in dripping on various parts of the engine below. If I had a engine under the companion way I would do away with the valve and plumb a line from the vent to the cockpit and allow it to dribble to a scupper, this does away with any risk of a sticking or leaking valve. But, being a mid mount engine I cant keep a line higher enough to run it to the cockpit. Im thinking of adding a galley pump spout over the sink and connecting the u vent to it and allowing it to dribble into the sink while engine is running. I believe I can make this asetically look fine although ideally I'd prefer another solution.
Thought, opinions or better ideas?All suggestions are welcome.
Cheers Dale
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Re: leaking vented loop

Postby Castaway » Sun Jul 19, 2015 10:06 am

I had a similar problem with a Volvo vent, which dribbled continuously when the engine ran, although there was never any back-siphoning. I ran a thin tube down to the bilge, and just pumped it out from time to time; usually only a litre or so after a day's run.

A few years ago, I bought a cheap plastic loop vent, which has worked well, and not leaked, for the past five years. Might be better that a pipe to the galley?
Gerald Freshwater,
s/y 'Castaway', (UK F35 cat ketch)
Lerwick Boating Club
Shetland Isles, Scotland
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Re: leaking vented loop

Postby rbrown739 » Sun Jul 19, 2015 9:00 pm

I had a leaky vented loop on my F32 and it eventually caused my external engine oil line to rust thru. Not good. I moved the line along the bulkhead to the port side where I was able to get it a bit higher and put a drip loop in the lines so that if leaked again it wouldn't be above the engine but only above the bilge. Seemed to work.
Carina, F32 (Hoyt)
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Re: leaking vented loop

Postby daletournier » Thu Jul 23, 2015 1:26 am

Thanks guys for the responses. I think im just going to add a longer hose (to elbow) and run it so the lowest point is aimed to the bilge, then if/when it dribbles it misses the engine completely. The ideal solution is to cut two holes behind the sink and mount a scott pump type loop on the bulk head. This is a high quality vented loop that would be mounted two feet at least above the waterline thus it should operate very well, but I can't live with the visual side of seeing the loop in my galley.
Cheers Dale.
Posts: 181
Joined: Wed Aug 18, 2010 6:25 pm

Re: leaking vented loop

Postby tnltracy » Mon Jul 27, 2015 8:28 am

Haven't noticed mine leaking, but haven't really watched it closely. Mine is raised up on the starboard side of the galley bulkhead, along the side of the basin. This has it away from the engine, but I'll have to look to see if any seepage could follow the lines back down toward the engine.
1984 Freedom 32 #28
Warwick Cove, Greenwich Bay, RI
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