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| Why are through hull fittings so long? |
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anon252
Visitor
| | Posted on Tuesday, February 07, 2006 - 03:11 am: | 
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My seacock for engine cooling in-take has a leak. (Off doesn't mean no water flows). It's a standard ball valve (no flange fitting, like those marketed as seacock). The arrangement of valve, fitting, tee (warm water return from thermostat), fitting is over 6" long. I think this offers too much mechanical moment to the hull and I would prefer to see this run of pipe fittings closer to the hull (increase risk of rotational moment without valve control for the sake of reducing risk of orthagonal moment acting on the hull).
The screened through-hull fittings for engine in-take I find in stores are 3" long or more, but I think my hull is less then 1/2" thick. Why is there so much excess length on the thread barrel?
I have no plywood footers to mount a 'seacock' type valve (the through-hull nut tightens directly to the fiberglass). Should I add such a foundation? I don't think the firming bolts add enough value to justify the addition risk of leak. (experience? application procedure?)
If I cut off the excess thread barrel to say 1 3/4 long, is there some risk I haven't thought of?
If I assemble a 90' fitting to the through-hull before the valve, I can place the valve in parallel to the hull plane. This would force the incomming seawater to follow a U-shaped flow. Would this increase the risk of clogging? Does anyone have experience with this layout? Is it a bad idea? Should I prefer an S-shape first and loop back to the water pump after the valve or filter? |
Dean
Visitor
| | Posted on Friday, March 03, 2006 - 03:14 am: |
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The palmer manual says to minimize bends on the intake as much as possible. I have no idea why this would matter for fixed pipe fittings, but the message seems clear for soft rubber tubing. Since the owners manual says that 3/8" intake is required, why would it matter if you have 3/4" intake with many 90' elbows or even 180' angles? |
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