Re: [PSUBS-MAILIST] Onboard compressor?

[VBra676539@aol.com]

I've seen diesel power done as a generator only, and also as a main engine 
with a big 36vdc alternator to whack some power into the batteries. I'm not 
sure why you'd want to mess with compressors unless you were building 
something big enough to run on its own for a week-end or something, and then 
you might need a couple of them. You could use a low-pressure, high-volume 
unit for your surfacing maneuvers (a reasonably sized home compressor, 
maybe?) and then save the tedious high pressure work for when you were 
underway and/or charging batteries on the surface. If you were using your 
diesel as a drive unit, then a clutched power take-off (John Deere, where are 
you?) might be the option you need. Alternatively, you could run your 
generator set and power all these devices seperately, each with its own 
motor, although it might be more expensive and cumbersome that way. Seperate 
compartment or not, it's going to be noisy in there when you run the diesel. 
Exhaust can be run through a flex pipe/hull-stop arrangement and can, in 
fact, be vented underwater. You'll have to fiddle the discharge angle so that 
a venturi is created while underway (angle it back) which will help avoid 
sucking up a big dollop of seawater, but it would be worth it to quiet the 
thing down and to give the engine some back pressure.
Vance