Thanks Joe. Backpressure was something I thought about after I sent the email, but I presumed that since the engine is only having to work against the differential pressure to force out the exhaust, then it should be able to run underwater. However, that's my own guess.
Heck, you could even set up a mechanical linkage between an airvalve and the throttle to dump extra air into the engine bay if it's running. Add a solonoid that automatically activates it when the snorkel is closed, and your engine bay gets a shot of air when the boat dips just below snorkel depth.
Let us know what Yanmar has to say. Inquiring minds want to know. ;-)
NP
From: "Joseph Perkel" <joeperkel@hotmail.com>
Reply-To: personal_submersibles@psubs.org
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Speaking of 1ATM construction...
Date: Sun, 22 Jan 2006 00:09:12 +0000
NP
Carsten mentioned something recently regarding Spurdog starting the diesel at depth to blow ballast with the exhaust but, as you noted, this is in a 1 atm boat. (Same as sea level). Too much negative pressure is not a good thing either.
In my ambient, I am anticipating exhaust backpressure issues to be resolved, partly by routing the exhaust up high in the sail. This is a potential deal killer for the 14 hp engine and I have yet to receive an answer from Yanmar on the subject.
Joe
From: "Nomdae Plume" <nomdae@hotmail.com>
Reply-To: personal_submersibles@psubs.org
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] Speaking of 1ATM construction...
Date: Sat, 21 Jan 2006 23:35:21 +0000
Will a diesel engine run in a pressurized environment? For example: If I had a 1ATM boat, and for some reason needed to run it at depth, (aside from the obvious huge consumption of air) would the engine run at all?
NP