[PSUBS-MAILIST] G.L. rules Arrangement for Diving/Ballasting, Control/Compensating & Trimming

[Alan James]

Joe,
It says in section 7 D 4.1...
"The capacity of compensating tanks has to be big enough to compensate for all the
changes in buoyancy expected to arise during the planned diving duties plus a 
reserve capacity of at least 10%.
I presume you could use the compensating tanks as a supplement to adjusting
buoyancy with weights.
   I wonder how those tourist subs get on with fifty people of differing weights who
aren't weighed before hand. And what about the trim? "Excuse me madam could
you move to the front of the submarine & swap seats with that skinny gentleman".
Alan


________________________________
 From: Joe Perkel <josephperkel at yahoo.com>
To: "personal_submersibles at psubs.org" <personal_submersibles at psubs.org> 
Sent: Monday, January 13, 2014 1:18 AM
Subject: Re: [PSUBS-MAILIST] G.L. rules Arrangement for Diving/Ballasting,	Control/Compensating & Trimming
 


Alan,

I've been giving this issue of fine buoyancy control some thought lately. In the literature is there any mention of a rule of thumb volume to vehicle ratio for the capacity?

On a K-350, the difference between diving solo or with a passenger could be as much as 200 lbs (100 kg). I would think that it would be convenient and useful to be able to compensate for this without having to manually transfer solid ballast (lead). The standard VBT volume is too small to be able to do so.

Joe

Sent from Yahoo Mail for iPad 



________________________________
 From:  Alan <alanlindsayjames at yahoo.com>; 
To:  Personal Submersibles General Discussion <personal_submersibles at psubs.org>; 
Subject:  Re: [PSUBS-MAILIST] G.L. rules Arrangement for Diving/Ballasting,	Control/Compensating & Trimming 
Sent:  Sun, Jan 12, 2014 9:20:37 AM 


Hi jim,
here's a G.L. quote. "Normally compensating tanks are to be provided for a fine
adjustment of the wanted depth and for balancing of changes of buoyancy
because of consumption of provisions & supplies during the underwater voyage,
changes of the density of seawater, taking on or taking off of payloads as well 
as effects of buoyancy/loss of buoyancy."
   This section covers hard & soft tanks, internal & external, & calls them all
compensating tanks.
Alan

Sent from my iPad

On 12/01/2014, at 9:59 am, jimtoddpsub at aol.com wrote:


Hi Alan,
>Thanks for posting that.  What all does "compensating tanks" refer to? 
>Best regards,
>Jim
> 
>-----Original Message-----
>From: Alan James <alanlindsayjames at yahoo.com>
>To: psubs.org <personal_submersibles at psubs.org>
>Sent: Fri, Jan 10, 2014 5:37 pm
>Subject: [PSUBS-MAILIST] G.L. rules Arrangement for Diving/Ballasting, Control/Compensating & Trimming
>
>
>Hi all,
>This is my G.L. summary of Diving/Ballasting, Control/Compensating & Trimming.
>It builds a little on a previous section "Stability & buoyancy".
>   All the ballasting controls & systems have to work under previously specified heel & trim requirements. Including when one main ballast tank is damaged.
>   It has to be possible to check these systems prior to diving.
>   The sub must be able to surface after the failure of a compensating tank.
>   Flooding & bilge openings are to be protected with grids, filters or strum boxes to stop the entrance of foreign matter.
>   All the operating units for controlling positive & negative buoyancy are to be grouped together & clearly marked on the control consul. This control consul is to have indicating instruments showing depth & trim.
>   Separate shut off valves are required for each ballast tank.
>   The vent valves are to be designed in such a way as to prevent unintentional opening.
>   Where diving tanks have flooding holes without means of closure, double shut-off
>valves "May" be stipulated for the vent pipe.
>   The blowing line for each tank has to have a separate shut off.
>   Blowing the tanks cannot cause an excessive over-pressure.
>   Where the diving tanks are pumped out there needs to be a closure valve & back up bilge pump. No excess under-pressure can be caused.
>   Compensating tanks are to be designed big enough for all the changes in
>buoyancy plus 10%
>   Compensating tanks need contents gauges to give continuous readings.
>   The compensating tank vent pipes need to be wide enough for maximum 
>inflow / outflow and designed so that water can't flow from them unnoticed in to the hull.
>   The volume of the trimming tanks is designed in such a way that all planned trimming situations can be adjusted by combined filling & emptying of the various tanks.
>Alan
>
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