[PSUBS-MAILIST] engine drive

Sun Aug 20 19:45:12 EDT 2017

Hi Hank,

I am a believer of putting the fuel outside the vessel in the form of a bladder.  

100 litres of diesel/petrol would weight about 83 and 75 kg resprctively so would be positive 17 or 25 kg flotation but if inside the vessel would be 83 kg negative and when empty would be 83 kg of unwanted flotation if diesel.  The additional safety of having a bladder outside is the biggest consideration. Hugh

From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of irox via Personal_Submersibles
Sent: Monday, 21 August 2017 11:02 AM
To: Personal Submersibles General Discussion
Subject: Re: [PSUBS-MAILIST] engine drive

Hi Hank,

one of the key dangers with gasoline vapor is that it's heavier than air, so it will pool inside the sub (this has not changed with advancements in ICE technology).   Even with good ventilation, purging the pressure hull of gasoline vapor may be tricky.

You could look at converting the engine to something which is lighter than air (hydrogen?), but this should under go a lot of research/experimentation to ensure it's safe.

There has been a lot of discussion of using gas engines in sub in the past (bionic dolphin uses gas, but this is more enclosed jet skii than submarine), none of which seemed yield a safe approach to this.

Could you cut open your hull to install the engine, then weld it up again?

Good luck,

  Ian.

-----Original Message----- 
From: hank pronk via Personal_Submersibles 
Sent: Aug 20, 2017 3:41 PM 
To: Personal Submersibles General Discussion 
Subject: Re: [PSUBS-MAILIST] engine drive 

Alec,

Yes it may be to scary, I will give it more thought.  I need more range, and my boat will not be ready for the spring of 2018.  It is bad enough I missed this season ;-(  I need a working submarine with reliable range and batteries will not do it.    

The danger is gas vapour reaching an explosive level.  That would mean a leak and no proper venting coupled with an ignition source.  Both these risks can be managed.  Diesel fuel in a hot enclosed environment is not as volatile but still not without risk.  In all fairness, you can't compare early antique engines with a modern-day Honda.  My options are limited with an 18 inch opening.  

Hank

On Sunday, August 20, 2017, 4:21:51 PM MDT, Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Sorry to be critical, but yes, from an historical perspective a gas engine would be a big no-no as gas powered subs were death traps prior to the adoption of diesel. I always say my subs are at their most dangerous in the shop, not in the water. This could be a situation where the drained gas engine is not dangerous underwater but is dangerous during surface transit. And frankly storing the gas outboard sounds like a bit of a challenge in itself.  I applaud original solutions, but this isn't one that sounds like a good idea, at least to me.

Gamma seems to have pretty good range on batteries, and I recall you're planning on the trailerable landing craft. Would the landing craft not obviate the need for an onboard ICE?

Cheers,

Alec

On Sun, Aug 20, 2017 at 7:50 AM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Hi All,

My diesel engine did not work out in the end, and 6 hp I suspect is a bit skinny.   I do have a beautiful 15 hp 4 stroke Honda outboard that has been converted to run a hydraulic pump inboard.  I converted it many years ago to power my sternwheeler but ended up with an antique engine. The engine is stripped down to a bare engine with external water pump and internal oil cooler.  The problem is, it is a gas engine, and that is a big NO NO or is it?   If the fuel supply is outside the hull and the engine is run out of fuel before a dive, then there is no fuel at all inside the sub while it dives.  An engine compartment blower fan can constantly circulate air through a duct to the outside of the sub.  I know as a rule it is considered a bad idea but with careful   installation it could be a very nice drive system.  This would be much quieter and smoother than a diesel engine.  The Honda would be very easy to remove from the escape pod if I need to escape.  The Honda 4 stroke is as reliable as even a Yanmar diesel.   I was bragging to a Honda mechanic one time that the Honda starts with two pulls in the spring.  He said it must need a tune up LOL  it should start in one pull.  

Hank

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