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Re: [PSUBS-MAILIST] Working on a new DBP design.
Huh? What?
Carl
John Pier wrote:
> Hello there,
> I dont receive anymore the mailing list , something s wrong?
> Somebody to reply please
> Herve
>
> ----- Original Message -----
> From: Gary R. Boucher <protek@shreve.net>
> To: <personal_submersibles@psubs.org>
> Sent: Monday, March 12, 2001 9:43 AM
> Subject: Re: [PSUBS-MAILIST] Working on a new DBP design.
>
> > Just a note to those concerned. Syntactic foam is great if you learn
> > how to use it. That is if you mix your own. I have some tips if anyone
> is
> > interested. This foam has a tendency to form air pockets inside that you
> > can not easily get rid of. This may not be a factor at low depths but
> when
> > you go deeper, they may collapse. SF should be mixed in a vacuum in such
> > cases. Flotech does sell the kits, but they DO NOT like to sell those
> kits
> > to people to do subs. They would rather know that they go to use in ROVs.
> > Also, the techspheres are no longer sold (As of last summer this was
> > the case) as a stand-alone product. They still use them as filler inside
> > syntactic foam. Some had a tendency to leak.
> >
> > Gary Boucher
> >
> >
> >
> >
> > At 07:09 AM 3/12/01, you wrote:
> > >Soren,
> > >
> > >Here is my input, for what it's worth...
> > >
> > >1. Differential thrust works well and is effective.
> > >Trolling motors are designed for optimum trolling
> > >speed and I haven't found them to be the most
> > >responsive - I can stop and back my sub in half a
> > >length using a single MinnKota 35T, but the
> > >accelerations seem painfully slow. That may cause
> > >problems when going for differential thrust.
> > >
> > >2. Syntactic foam is readily available - check out
> > >flotec.com. They also have "techspeheres" which are
> > >plastic spheres capable of withstanding the depths you
> > >are interested in. Last time I checked, a huge box of
> > >these was just over $100. Blocks of foam are also
> > >available and can be machined to shape, either by them
> > >or by you. Alternatively, you could check out
> > >high-density styrofoam. It comes in sheets and is
> > >normally used for insulating homes, but it serves as a
> > >dandy float.
> > >
> > >3. Using plywood as a pressure vessel is a really bad
> > >idea in my opinion. Plywood is really flexible, hard
> > >to join effectively, and is somewhat porous. To build
> > >something to withstand even 30 feet of depth out of
> > >plywood would be an engineering feat. Once submarine
> > >I saw had two square pressure vessels built for its
> > >onboard computer system - these were maybe 18 inches
> > >square and about 6 inches high, custom designed and
> > >built out of carbon fibre about an inch thick. They
> > >experienced severe distortion at 50 feet. Be wary -
> > >having water flow into your exposed battery
> > >compartment could possibly kill you.
> > >
> > >4. The depth rating of the motor depends entirely on
> > >its design. There are underwater thrusters out there
> > >with a lot of power and torque, rated to 6000 feet of
> > >depth, but they also carry a huge price tag. I am
> > >working on a set of low cost, high power,
> > >oil-compensated, full-ocean depth thrusters with
> > >intelligent motor systems because I am not happy with
> > >anything else available.
> > >
> > >5. Underwater connectors are pretty easy to come by -
> > >I get mine from a guy in Halifax - DASCO Equipment
> > >(Dave Stewart is the guy). He reps Subconn Underwater
> > >Connectors, and they are by far the best quality ones
> > >I have used. Dave overnights me connectors when I
> > >need them, and his prices are lower than anywhere else
> > >I have tried. His email is dastewa@ibm.net, or you
> > >can find him if you search under DASCO Equipment on
> > >the net. They have big fancy catalogs that he can send
> > >with all the info in them - a typical 4 pin bulkhead
> > >connector and pigtailed in line connector will run you
> > >$120-$150 or so. They are pricey, but work really
> > >well and are easy to use - also wet-pluggable.
> > >
> > >6. No help here, sorry!
> > >
> > > -Tim
> > >
> > >
> > >
> > >Hi Everybody,
> > >
> > >I'm new to the list, but have done some research, incl
> > >searching the psubs archives, and I'm impressed with
> > >what people are doing.
> > >I got here after deciding to enhance my diving
> > >experience by building a long range / long endurance
> > >DPV.
> > >I have some ideas, and would love to get some feedback
> > >by all the experienced people here.
> > >First, a quick overview of my ideas so far. I like the
> > >principles of KISS, so my plan is the use painted
> > >plywood sheets as frame construction material, and, as
> > >I'm an electronics engineer, use electronic controls
> > >as much as possible.
> > >My target deep is abs max 200', usefull deep 130', air
> > >for 3-4 hours (using 4 80cf tanks), topspeed whatever
> > >I can get from std trolling motors and range 4-8 miles
> > >roundtrip.
> > >The basic design is when viewed from the rear:
> > >o o|
> > >I Diver I|
> > >O |I I| O
> > > ----|-------------|----
> > >O | Batteries | O
> > >-------------|
> > >
> > >
> > >And viewed from the side:
> > >
> > > /----------------------------\
> > > / |
> > > / [ ] |
> > > < --------------------- |
> > > \ [ ] |
> > > \ |
> > > \----------------------------/
> > >
> > >It's basically a H, with four electric engines 'O',
> > >fixed lift on top 'o', thin variable lift tanks 'I',
> > >battery box below, about where the engines are
> > >located, and 4 std scuba tanks in front of the
> > >batteries. The side sheets would be a 2x7' sheet, but
> > >with big pieces cut out to reduce weight and improve
> > >view. The 'H' mid sheet is 3' wide, where the diver
> > >would lay on, would be solid from the rear and 5'
> > >forward, leaving room for the diver to look down. All
> > >weights will be at the bottom, and it will have wings
> > >for stability during "flight". I would be designed to
> > >be modular assemblies for easy transport.
> > >So here comes the questions:
> > >1) I'm trying to avoid mechanics, so is it possible to
> > >get good results by using only the four engines for
> > >left/right and up/down control by controlling power to
> > >each engine, assuming the DPV has been set for neutal
> > >balance and buoyancy using the variable lift tanks ?
> > >2) I like those syntactic floats for the fixed lift,
> > >are they easy to get in the shape I need (long square
> > >blocks or pipes), or can I get some standard blocks I
> > >can cut to shape ? And sources for normal people ?
> > >3) I would like to avoid pressure compensation, would
> > >a battery box of plywood be able to withstand the
> > >pressure, assuming it has internal support brackets
> > >between each battery and the sealings holds ?
> > >4) Again for the engines without pressure
> > >compensation, would they be able to withstand the
> > >pressure if the shaft is sealed with t.ex silicone ?
> > >There has been some discussion of that in the
> > >archieves, but not any conclusive if no pressure
> > >compensation is used. Somebody talked about that the
> > >Evinrude can go deep, but I would like to use Minn
> > >Kota's, as they seem to have plenty of choices at good
> > >prices.
> > >5) Anybody know a good sources for the underwater
> > >connectors in small quantities and low prices ?
> > >6) Sources for valves to fill and empty the variable
> > >lift tanks ?
> > >And any good ideas and/or sources for the tanks ?
> > >
> > >Regards,
> > >
> > >
> > >Soren Kristensen
> > >
> > >
> > >__________________________________________________
> > >Do You Yahoo!?
> > >Yahoo! Auctions - Buy the things you want at great prices.
> > >http://auctions.yahoo.com/
> >
> >
--
Remember- First you pillage, THEN you burn.