Intake seacock & strainer in 5.5-inch bilge

[Alii]

I need to install an engine intake thru-hull, seacock and strainer in a bilge compartment that is only 5 1/2 inches high. I have an area around 9" x 2 1/2' to work with. This will supply a 1" ID hose that runs about 12' then through a SeaFrost condenser before the seawater pump on the Yanmar 4JH2E.

So far what I've come up with is the Forespar Marelon 93 Series OEM Smart Valve (combination thru-hull/ball valve) 1.25" (I will need to take half an inch off the handle for clearance in open position), and the Forespar MF810 water strainer with an adapter down to 1 inch. I will need to modify the large handle on top of the strainer, as reported height overall is 6.1". The strainer would be well under the waterline, but I would have hardly any hose that could clog or kink between the valve and the strainer (versus the long twisting run that would be needed to put the strainer above the waterline).

Any experience to share with these two Forespar products? Or perhaps someone has dealt with a similar situation and come up with a better solution?

Thank you for help with brainstorming,

Alii

[sanibel sailor]

Easy for me to say, but I would try for a dedicated engine intake without putting the condenser inline.

There are lots of Marelon valves, go to their website and look under OEM stuff. Be aware that some of their seacocks have a proprietary thread pattern. I discovered this when an assistant cross threaded the thruhull on a valve. I assumed a quick trip to West Marine would fix it... Turns out it was not standard pipe thread, so no other fittings would work. Forespar was nice enough to send a new one immediately at no cost, no questions asked.

[The Way]

I'm no expert, but I thought the strainer had to be above the waterline to avoid syphoning.

Fair winds,
Jack

[sanibel sailor]

Originally Posted by The Way

I'm no expert, but I thought the strainer had to be above the waterline to avoid syphoning.

Fair winds,
Jack

no. it is basically a closed system, although there ought to be a siphon break before the injection elbow.

now if that strainer lid becomes ajar...

[sanibel sailor]

Boat Marine Plumbing OEM Smart Valve Thru Hull

OEM valves, notice there is a valve with two outflows

[HopCar]

My favorite way to make a low profile seacock is to use a Groco Flanged Adapter, a street elbow and a Groco ball valve.
Using 1" fittings I think it would end up at just 5-1/2" high. If it is something you think you might like to try, I can put one together and measure it for you.
Groco Flanged Adapter IBVF
ACR Bronze 90 Degree Street Elbows
Groco Full Flow In-Line Ball Valves (IBV series)

[Alii]

"Easy for me to say, but I would try for a dedicated engine intake without putting the condenser inline."

Yes, sanibel, easy to say but impossible to do. There is nowhere to put a second thru-hull plus strainer plus pump plus discharge to supply a separate water source to the condensor. Glad to hear you've had good support from Forespar.

I have an anti-siphon loop between the manifold and the mixing elbow. I thought the rationale for recommending mounting strainers above the waterline was to avoid leaks. I don't think this concern is unique to Forespar (or to this Forespar model), pretty sure Groco recommends the same thing.

Thank you HopCar for the photo and offer to help re the Groco components. This is pretty much what we have had for our watermaker and head intake -- except in 316, which proved to be of poor quality (I have a separate post on that issue) -- and we've just replaced those thru-hulls with the Forespar Series 93 3/4".

If I go with this Groco configuration .. what about the strainer? I believe all in the Groco line are too large for my space. It looks like this Forespar MT810 accommodates a lot of flow and a lot of contact area with the screen. I like the idea of being able to inspect it visually, and clean it so easily.

Alii

[Alii]

Sanibel, I had misinterpreted your post about the OEM valve with 2 outflows. You're suggesting using one valve to supply both the engine and the condenser separately? Hmmm ... I will still need a strainer, a pump, and a discharge port on the condenser line.

[Alii]

HopCar, one thing we've had to do with the Groco-type set-up is to position the handle under the valve. We have reasonable access and swing room in the bilge to get to the handle.

[HopCar]

" I believe all in the Groco line are too large for my space."
I think you're right, use the Forespar strainer.


"HopCar, one thing we've had to do with the Groco-type set-up is to position the handle under the valve."
I'm pretty sure that would put it under your 5-1/2" height limit.

[Cadence]

Originally Posted by Alii

I need to install an engine intake thru-hull, seacock and strainer in a bilge compartment that is only 5 1/2 inches high. I have an area around 9" x 2 1/2' to work with. This will supply a 1" ID hose that runs about 12' then through a SeaFrost condenser before the seawater pump on the Yanmar 4JH2E.

So far what I've come up with is the Forespar Marelon 93 Series OEM Smart Valve (combination thru-hull/ball valve) 1.25" (I will need to take half an inch off the handle for clearance in open position), and the Forespar MF810 water strainer with an adapter down to 1 inch. I will need to modify the large handle on top of the strainer, as reported height overall is 6.1". The strainer would be well under the waterline, but I would have hardly any hose that could clog or kink between the valve and the strainer (versus the long twisting run that would be needed to put the strainer above the waterline).

Any experience to share with these two Forespar products? Or perhaps someone has dealt with a similar situation and come up with a better solution?

Thank you for help with brainstorming,

Alii

That 12' run seems a little long to me?

[Alii]

I called Forespar to request detailed dimensional drawings and other info on the MF810 strainer. The gentleman said he would see IF there was anything he could send to me. We'll see...

He also said they are shipping 500-600 of these strainers a month to various builders who are all installing them under the waterline.

If anyone out there in the course of their Xmas shopping happens to see one of these MF810 strainers, could you take a look and offer an opinion whether I can bring the overall height under 5 1/2 inches by taking down the stem on the knob on top of the lid? Do you see mounting options on the bottom of the bilge rather than on a bulkhead, perhaps using something other than the supplied bracket? (I'm in Malaysia or would do this myself.)

[Alii]

I agree, Cadence, the hose run is long. The only bilge compartment deep enough to accommodate the seacock is mid-ship next to the bilge. The hose is threaded aft through 2 other very shallow compartments, takes a right turn behind the engine, then comes up to the condenser.

The set-up has worked for 28 years, provided I use only Yanmar original impellers (the OEM Johnson variety are too soft).

[oceaneer]

Im wondering about your impellers and the too soft comment..
I have been butting a little loop in the seawater lines before the raw water pump to keep it flooded all the time. (like a P trap)
This really helps as most impellers burn out on start up from being dry.
THanks
Oceaneer

[Alii]

Hi Oceaneer -

The water pump is much lower than the condenser and water remains in that hose when the engine is stopped (and started). Only the stiffer vanes on the Yanmar impellers have enough oomph to deal with the long intake hose plus upstream condenser. Yanmar says to replace the impeller every 600 hours and that's pretty much when they start to fail on me.

Alii