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Hi Brian. That makes good sense. Save a few bucks and go with what works.
As for matching up the two materials, There's always going to be the corrosion
factor to deal with. Zinc sacrificial anodes will help but not eliminate the
problem. On the plus side, bronze and stainless won't "gall" when screwed
together. I'm using a lot of brass bolts mated to stainless lock nuts. Although
replacement of the brass will be needed sooner than stainless bolts would, at
least I know I'll be able to get them apart without a big hassle. Some places
I'll be using stainless bolts and brass nuts, because I need the extra shear
strength of the stainless, but again, it comes apart easily after a long time in
salt water.
I too am going with the bronze valves. They are pressure
rated to 600 psi, are cheap to replace, and when polished they look really good.
Very "Capt. Nemo" like. Also, the highly polished surface corrodes much slower
than the regular cast surface. I've got quite a few of the interior valves,
unions, elbows, nipples, and related bushings and adaptors and when polished,
they look really good. The HP air will be like yours, Swagelock and stainless
tube.
I haven't cut in any through-hulls yet, but those will
all be stainless nipples. Then a bronze ball valve on each one where it enters
the sub. Complete shut-off at every penetration if a problem develops. Even the
electrical through-hulls will be valved off. I want to get all the components
mounted before I start cutting in the nipples. The largest is 2 inch, while the
smallest is 3/8 inch. The main ballast will all be 1 inch. Maybe a little slow
to submerge but I don't expect that to be a problem.
You said you're using rod linkage to operate your
valves? Wouldn't a small hydraulic cylinder work just as well?
When the weather gets a little better, I'll cruise
down on my bike for a visit and a cold beer. Frank D. |