[PSUBS-MAILIST] Dive report - Pickles Reef

[Jon Wallace]

Hi Marc,

I don't understand how renewal of the ambient tropic air will help with environmental comfort to the point of not requiring some kind of air conditioning.

Jon


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On Thu, 10/10/13, Marc de Piolenc <piolenc at archivale.com> wrote:

 Subject: Re: [PSUBS-MAILIST] Dive report - Pickles Reef
 To: personal_submersibles at psubs.org
 Date: Thursday, October 10, 2013, 10:15 PM
 
 I've been following this discussion
 with great interest. I don't have a sub yet, but I do live
 in the Tropics, and as there's no cold current handy to
 where I live any subbing I do will be in water pretty near
 air temperature. As you might expect, I've given this
 problem a lot of thought.
 
 My tentative conclusion is that, if I build a sub, I will
 have to make it more autonomous than is the rule on this
 list. Specifically, it will need a combustion engine to
 ferry itself on the surface to dive sites, and to maintain
 comfort and keep the battery topped off for diving while
 doing so. I started with the assumption that I would need an
 air conditioning unit running off a small industrial diesel,
 but then I realized that, if I use a snorkel exhausting into
 the cabin, and have the diesel draw air from the cabin, I
 get continuous renewal of the air in the cabin without the
 cost, power burden and safety problems of running a Rankine
 cycle refrigeration system. That's the solution that I've
 retained for the moment. Of course I also need a secure
 means of preventing exhaust gas from being aspirated into
 the snorkel (I can't quite understand how naval submarines
 manage to combine both functions in one mast), but that
 might be as simple as having the diesel exhaust flush with
 the hull, with some arrangement to prevent water from coming
 in. Since the diesel would only be used on the surface, and
 the snort would only be there to allow a low-freeboard hatch
 to be kept closed, the power penalty would be minimal.
 
 Fuel storage, fuel feed and the like still have to be worked
 out. Naval submarines have very complex arrangements for
 this, and that complexity must be tolerated for a good
 reason. Even so, I need a simpler way to do it that still
 protects the fuel from contamination and me from
 asphyxiation.
 
 Marc de Piolenc