[PSUBS-MAILIST] Diesel Exhaust

[Hugh Fulton]

Hi Marc,

I am in the final throes of finishing twin engine driven 2 man and I have
opted for the following:

 

2 x 2” Snorkels with plastic float valves leading into the cabin through 2 x
2” combination valves being manual ball valves coupled to air actuated
shuttle valves and fitted with non return valves.

This means that the non return valves will vent overpressure situation on
the surface and blow out through the snorkel float valves.

The snorkels are located inside an airbox leading into the boat part which
has about 4 cubic meters of air volume so that if I go through a wave the
float valve does not get to close and the air is drawn from the “air box”
volume for a brief period.

The air is then drawn from the cabin again through 2 x combination valves
into the engine pressure chambers.  The exhaust which also takes a large
portion of the engine cooling water goes through a raised exhaust line above
the water level then down through an air operated shuttle valve and a non
return valve exiting underwater through the center of the propeller as per
an outboard motor or stern leg.   According to the rules you should have 2
valves on the exhaust.  I am relying on the air drawn through the cabin for
cooling and as most of the cabin is protected by fiberglass I am hoping that
it wont get too much direct heating from the sun apart from through the
domes.  When the air operated shuttle valves are closed ready for diving the
engines will pull a vacuum of approx 1-2 psi before shutting down.  IF no
vacuum maintained then no dive and the engines keep running.  All untested
yet but hoping I am only about 8 weeks away.  Carsten’s system is all tested
and proven.  Regards, Hugh

 

 

From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org]
On Behalf Of 
Sent: Saturday, 12 October 2013 6:33 a.m.
To: Personal Submersibles General Discussion
Subject: Re: [PSUBS-MAILIST] Diesel Exhaust

 

Hi Marc,
 
before I response in detail, which size should the sub have? And which
range?

And which kind of wave high, wave length and weather you want to survife on
the surface?
Any concept sketch? Do you like to snorckel with the sub? 

Euronaut has more problems with the short medium high wave in the baltic 
than with the high but long waves in the north sea.
 
Bad weather in the north sea lift the hole boat before the wave reach the
sail, but in the Baltic the waves are 
shorter and did mot lift the boat so much - as result the sail goes very
wet. Like in the movie "Das Boot"

Short wave in the baltic: 
http://www.euronaut.org/content/gfx/operational/IMG_8705.jpg

Here the over waterline exhaust of Euronaut in operation. 
The funny sound comes from a wave flap close to the end of the exhaust 
which goes up and down at idlle speed. 
http://www.youtube.com/watch?v=PT7i05s92ak

Cooling is also something you should have in mind. 

And noise.. 

And..

vbr Carsten



From: Marc de Piolenc <piolenc at archivale.com>
To: personal_submersibles at psubs.org 
Sent: Thursday, October 10, 2013 10:15 PM
Subject: Re: [PSUBS-MAILIST] Dive report - Pickles Reef


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

-- 

Carsten Standfuß
Dipl.Ing.Schiffbau @ Meerestechnik
Heinrich Reck Str.12A
18211 Admannshagen

0172 8464 420
WWW.Euronaut.org
Carsten at euronaut.org 

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