[PSUBS-MAILIST] Saddle Tank Vents

[James Frankland <jamesf@guernseysubmarine.com>]

Hi All,

 

I'm nearly done with my hatch locking mechanisms and will be starting on the main tank assembly very soon.

 

http://www.guernseysubmarine.com/Extended_files/Page6497.htm

 

I have made the sub as per the plans to take the standard K350 main tank assembly.  I was intending to make part of the front tank contain "viewports" so as to not destroy the view from my new dome.  Similar to Doug Privitts sub.  But im really very tempted to change the design to use saddle tanks instead.  This would be for 2 reasons, first it would not obstruct my front dome and second, the tanks could be completely enclosed (appart from the holes at the bottom) which would make the boat a lot more resistant to accidental flooding of the tanks.   The waters around here can be a little bit choppy even on nice days, so i'd prefer the stability of completely enclosed tanks.

 

Anyway, the problem is that i have the vents and high pressure air in the "standard" places.  OK, the HP air wouldnt be too difficult to route to a saddle tank but the vents are not as easy.  i only have 1 vent per tank and im pretty sure i should have the ability to vent either front or back or the tanks.  So if the subs longitudinal trim changed and it tipped forward or back. i'd still be able to complete the vent. 

 

Option 1 is to put a vent pipe from the back of 1 tank, passing along the top to the front of the tank where it joins to a second vent hole and then combined, they go to my valve.  I dont think this will work as im sure if it tipped the wrong way, i'd get an airlock even though there was a vent there.

 

Option 2 is to pipe both tanks front vents together to 1 valve and similarily both tanks rear vents together to the other valve.  Even so, with the position of the rear vents relative to the valve, i still may get airlocks.

 

Sorry its a bit difficult to understand written down, i should have drawn a picture but im at work, just thinking about what to do...

 

Any suggestions?  What have other people done for saddle tank vents?

 

Kind Regards

James