[PSUBS-MAILIST] Propane sub

[CWall@swri.edu]

	Yes we can get back to a technical discussion. I might proffer
that while a propane engine might provide an excellent means of generating
both locomotion and/or power, it might be better used to power a
compressor and use air as your deballast gas. That way you aren't using
fuel to deballast your tanks, just readily available air. Subs using
air-breathing or even air-independent engines to power compressors at the
surface have a long and proven track records for increasing range at sea.
If that's your goal, you might consider looking at that option rather than
deballast with propane. People do this with diesel already, right?
	It is totally possible that I have missed the point on this one.
If that's the case, don't take my response as a personal attack.

						Thanks,

							John

The answer I'd offer to your comment is that this sub is not designed to go
deep- the propane will be useless below 150 ft or so, and I don't want to go
anywhere near that deep- and I will have the droppable ballast to prevent that,
 even if I run out of propane with all ballast flooded.

With dives in the 15-30ft range, it doesn't take much to get back to the
surface, and most dives will begin near neutral ballast and surface without
blowing- powered submergence, in other words, so it won't be propane intensive-
 and when I do blow ballast for more freeboard, I'll be burning most of it off
for power when I want to sink again.

I really think it can be very economical, IF the operator wishes it to be.  It
does mean than the style of operation will have to be adjusted- but crash dives
 are not something I put a premium on in the first place in any case.  

Craig Wall