[PSUBS-MAILIST] Ballast Tanks

[Alan via Personal_Submersibles]

Hank,
I managed to interpret that email & In my calculations I forgot about putting a burst
of compressed air in to get the water completely out, although I was automatically
doing that when I was diving.
A bit of a no brainer now for me to have a free flooding ballast tank. 
Alan

> On 19/05/2020, at 12:08 PM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Alan, I know after laughing Gamma I always gave a boat of air to make sure all was open and good.  I could not quantify the amount but know there is not much difference.
> Hank
> 
> On Monday, May 18, 2020, 6:00:12 PM MDT, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> 
> Just did some experiments & answered my own question.
> If you put an upturned glass in a container full of water & push it down till
> it is just fully under the surface, the water enters the bottom of the glass to
> a level that is 6% of the volume of the glass.
> This is less than what I thought. You would only gain 6% more floatation by
> going from a free flooding ballast to having a flood valve.
> The pros of having a flood valve are the added floatation & added security that 
> your sub won't sink if the vent valve fails.
> The cons are that you would need a much larger valve than the vent valve 
> & there would be more pressure in the ballast tank when blowing the ballast.
> Alan
> 
> > On 18/05/2020, at 7:45 AM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> > 
> > Has anybody got an idea or guess as to how much water comes in to
> > a free flooding ballast tank? Ie. would it fill up to 1/4 of the volume
> > of the tank with water? And does this vary much after towing.
> > Also if you know the volume of your ballast tank that would be helpful.
> > Am considering inlet valves at the bottom of the tanks as I will be towing 
> > the sub a lot.
> > Thanks Alan
> > _______________________________________________
> > Personal_Submersibles mailing list
> > Personal_Submersibles at psubs.org
> > http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
> 
> 
> 
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20200519/b354eeb3/attachment-0001.html>