Re: [PSUBS-MAILIST] K350 Parts

["Rick and Marcia" <empiricus@telus.net>]

Hi, Dean - your operating depth will determine whether you'll be using LP or
HP air.  I would have to assume you're not diving too deep, maybe 10 at's?

Joe's right - Boyle's Law will bite you.  Anyone who's ever used a buoyancy
compensator or, god forbid, a dry suit knows how difficult maintaining
neutral can be.

A one-at trim system is simple to design and operate and, again, depending
on depth, doesn't have to be too heavily built.  An internal pump that
remains at one-at within the tanks can shift water back and forth or
laterally to control pitch and roll to accomodate passengers, etc.
Regarding depth control, you'd be using valves to admit water or air from
cylinders.  Attempting neutral at the beginning of your dive gives you the
surface as a reference and a large cushion in case you mess up.

Check with some of the experienced psubbers for actual LP and HP usage.

Cheers
Rick L
Vancovuer


----- Original Message -----
From: "Joseph Perkel" <joeperkel@hotmail.com>
To: <personal_submersibles@psubs.org>
Sent: Saturday, December 30, 2006 10:13 AM
Subject: Re: [PSUBS-MAILIST] K350 Parts


> Dean,
>
> Many times I have thought of this as well...(Why not use small shots of
air fore and aft for trim?)...seems simple enough...... But, the MBT's are
ambient......
>
> The problem is the dynamic nature of the bubbles with depth changes. Here
you have the vents closed to keep the the bubbles where you want them and
that's where the trouble starts. Start to change depth significantly, and so
change the size of these bubbles...larger (ascending) smaller
(descending)....there so there goes your fine trim and control.
>
> It's best for these types of trim systems to be hardened.
>
> Joe
>
>
>
>
> --------------------------------------------------------------------------
----
>   From: Recon1st@aol.com
>   Reply-To: personal_submersibles@psubs.org
>   To: personal_submersibles@psubs.org
>   Subject: Re: [PSUBS-MAILIST] K350 Parts
>   Date: Sat, 30 Dec 2006 12:03:57 EST
>
>
>   I have read many posts discussing secondary bt
>   for fine neutral control.
>
>   My question is can't the mbts be used for this?
>   It seems to me it could be done by using a simple
>   method.
>
>   my thoughts are to put 2 inline control valves on the
>   hp air line. the valve closest to the mbts would be left
>   open and the 2nd one would operate normally. Then
>   when fine control is needed, you would close the front
>   valve, open the back valve then close it. This would allow
>   a small amout of hp air to be delivered giving fine tuning.
>   the same could be done on the air release side.
>
>   The amount of control would be the volume between the two
>   valves.
>
>   So am I ignorant again? am I missing somthing here?
>
>   just a planning away
>   Dean Ackman
>
>
> ************************************************************************
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