Re: [PSUBS-MAILIST] Practical motor

[irox <irox@ix.netcom.com>]

Electric trolling motors filled with oil.  On ebay you can find all sorts
of trolling motors and just about all costs (from ~$100 to $1000).

Ian.

-----Original Message-----
From: Alexander Foreman <alexforeman@mailworks.org>
Sent: Mar 31, 2004 4:09 AM
To: PSubs Mailing List <personal_submersibles@psubs.org>
Subject: [PSUBS-MAILIST] Practical motor

Does anyone know if there is a low cost elecric motor that needs little
or no modification (except for pressure compensation) that comes with a
waterproof housing and can be used down to 100 feet?

On Mon, 29 Mar 2004 07:45:35 -0700, "Coalbunny" <coalbunny@vcn.com> said:
> Why not have an additional air tank and inflate "ballast tubes", raising 
> the sub a few inches?  He'll be on the surface, so he can refill his 
> tanks with a small 12vdc compressor (if he wants), and if in a crisis 
> underwater, he can also inflate the same tubes and add to his bouyancy.
Inflateable ballast bags - I think the problem with these is deflating
them cleanly and storing them when diving. The bags will nead to be
inflated when entering the sub prior to diving - to maintain hatch
clearance.
Maybe the bags need to be stored in a fairing of some kind, but them
might as well have bigger ballast tanks.

> Otherwise, I'd suggest not flooding the sail.  That's the part I fail to 
> understand.
> Carl
I presume you're a 1ATM oriented submariner.
Because the 1 ATM boat will be very heavy anyway, adding a conning tower
makes only a small difference to the boat's overall weight.
In some ambient designs, weight is critical. The structure of the boat is
light so overall weight is determined by lead ballast added to compensate
for displacement.
If the conning tower is NOT necessary for submerged operation, but IS
necessary for surface operation, then flooding the conning tower when
submerging seems the logical option.
Flooding the tower reduces the amount of water the boat must displace,
and therefore reduces the amount of lead ballast required.
The difference can be measured in pain and hardship whilst launching a
heavier sub.

Of course, this is only one of many options, as you and others have
pointed out.
-- 
Alexander R Foreman
Port Lincoln, South Australia
Sub - Research stage only
    - Small dry ambient

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