RE: [PSUBS-MAILIST] air pressure in ballast tank while surfacing

["Jens Laland" <laland@artematrix.org>]

Hugh

[it appears that my first attempts to post this message, with attachments,
simply failed... so here is a stripped version without the images]

** What sort of a pump.

I wasn't thinking of a hand pump, but a manual pump: something like a
pedal driven membrane ('bellows' is probably more to the point) pump with
chain & sprockets (bicycle overdrive) and a small fly wheel.

** A hand pump would be a bit slow!

Yes, and that's why I hope my own idea of a pedal driven pump would
perform somewhat better.

** Spa pool pumps are very fast and good.

I thought of that, but they do consume electric energy.

** I am doing similar but with closed buoyancy and using a pool pump to **
pump out the water rather than an Air pump to pump in the air.

This is interesting, and gets me thinking of the Seehund (ww2 midget sub)
and how one of its crew were able to drive the boat at full speed upwards
and as they broke the surface, with a hand on the air vent valve of the
forward ballast tank, ready to close it the very split second the the boat
stopped 'in mid air'. This way, with the forward end of the boat now
barely afloat, they used the hand pump (ref. attached photos) and 'pumped
out the remaining water' (I assume they referred to the forward ballast
tank only, and used compress air to blow their aft ballast tank). This
bilge pump could handle 70 liter (18.5 gal) per minute (at 90 double
strokes).

Best regards,
Jens Laland

PS.: Images can now be viewed here: http://traktoria.org/files/seehund/pumps/




************************************************************************
************************************************************************
************************************************************************
The personal submersibles mailing list complies with the US Federal
CAN-SPAM Act of 2003.  Your email address appears in our database
because either you, or someone you know, requested you receive messages
from our organization.

If you want to be removed from this mailing list simply click on the
link below or send a blank email message to:
	removeme-personal_submersibles@psubs.org

Removal of your email address from this mailing list occurs by an
automated process and should be complete within five minutes of
our server receiving your request.

PSUBS.ORG
PO Box 53
Weare, NH  03281
603-529-1100
************************************************************************
************************************************************************
************************************************************************