> > > Look at car wash pumps. They are usually positive displacement piston
> > pumps designed for hard use. Available from about 25 psi on up to 1000
> > without going into specialty units.
> > > Vance
> > >
> > > Sent from my iPhone
> > >
> > > On Feb 29, 2012, at 4:12 PM, "Hugh Fulton" <
hc.fulton@gmail.com> wrote:
> > >
> > > > Brian,
> > > >
> > > > If you can find something off the shelf then I would love to know.
> > Saltwater, pump, 250 psi, 10 gpm. Not easy to find but I am in NZ.
> > > > USA should be much easier to find something. Does anyone else have
> > any experience with this??? Hugh
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > From:
owner-personal_submersibles@psubs.org [mailto:
> >
owner-personal_submersibles@psubs.org] On Behalf Of ojaivalleybeefarm @
> >
dslextreme.com
> > > > Sent: Thursday, 1 March 2012 9:29 a.m.
> > > > To:
personal_submersibles@psubs.org
> > > > Subject: Re: [PSUBS-MAILIST] Hard ballast inside P. hull
> > > >
> > > >
> > > >
> > > > Hugh,
> > > >
> > > > Ok, I agree, it just seemed like you had to do a lot
> > of modification to your pumps. Is there nothing off the shelf that would
> > do the job? Do you have some good sources for those pumps?
> > > >
> > > >
> > > >
> > > > Brian
> > > >
> > > > On Wed, Feb 29, 2012 at 11:49 AM, Hugh Fulton <
hc.fulton@gmail.com>
> > wrote:
> > > >
> > > > Vance would know more about how common it is but fighting for space
> > inside is a common thing. Moving the water with air pressure is fine but
> > what do you do with the exhaust air as to get rid of it would mean fighting
> > against outside water pressure or compressing it inside the transferee tank.
> > > >
> > > > I believe it is better to have access outside as then you can
> > compensate for different weight of passengers and also compression of the
> > vessels, difference in temperatures, fresh to salt water options etc.
> > Easier to use a manual bilge pump to transfer if you are having it inside
> > and then air into one tank equals air out. I am following the Comsub HBT
> > system with the motorized pump and 2 tanks with a relief valve on each tank
> > so if the pump fails I can blow with air to remove the water against the
> > relief. My penny’s worth. Hugh
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > From:
owner-personal_submersibles@psubs.org [mailto:
> >
owner-personal_submersibles@psubs.org] On Behalf Of ojaivalleybeefarm @
> >
dslextreme.com
> > > > Sent: Thursday, 1 March 2012 7:24 a.m.
> > > > To: personal_submersibles
> > > > Subject: [PSUBS-MAILIST] Hard ballast inside P. hull
> > > >
> > > >
> > > >
> > > > Hi,
> > > >
> > > > I'm thinking of having my hard ballast located inside
> > my pressure hull and controlling it's contents with air pressure. So I
> > guess it will have to be rated equal to my pressure hull. One reason for
> > doing this is simply for logistics as far as how my sub is laid out and how
> > I have to locate things. I could change this in the future to have the
> > hard ballast outside if I can find a good place for it..
> > > >
> > > >
> > > >
> > > > I was toying around with the idea of having fore and aft trim tanks
> > using hydraulic fluid as the medium for transferring weight fore and aft.
> > That way I wouldn't have to worry about corrosion in the pump, even though
> > the oil would not have the weight of water.
> > > >
> > > >
> > > >
> > > > Is locating a hard ballast inside the pressure hull a common thing
> > to do?
> > > >
> > > >
> > > >
> > > > Hugh, any thoughts?
> > > >
> > > >
> > > >
> > > > Brian
> > > >
> > > >
> > > >
> > > > __________ Information from ESET NOD32 Antivirus, version of virus
> > signature database 6925 (20120229) __________
> > > >
> > > >
> > > >
> > > > The message was checked by ESET NOD32 Antivirus.
> > > >
> > > >
> > > >
> > > >
http://www.eset.com
> > > >
> > > >
> > > >
> > > > __________ Information from ESET NOD32 Antivirus, version of virus
> > signature database 6925 (20120229) __________
> > > >
> > > > The message was checked by ESET NOD32 Antivirus.
> > > >
> > > >
http://www.eset.com
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > __________ Information from ESET NOD32 Antivirus, version of virus
> > signature database 6925 (20120229) __________
> > > >
> > > >
> > > >
> > > > The message was checked by ESET NOD32 Antivirus.
> > > >
> > > >
> > > >
> > > >
http://www.eset.com
> > > >
> > > >
> > > >
> > > > __________ Information from ESET NOD32 Antivirus, version of virus
> > signature database 6926 (20120229) __________
> > > >
> > > > The message was checked by ESET NOD32 Antivirus.
> > > >
> > > >
http://www.eset.com
> > >
> >
> >
> >
> >