Diesel/Electric Propulsion System Design - Have your say!

Hi again CatBuilder,
Have you considered RO watermaker Au$4500 for about 60 litres/hour running on mains power http://www.blueseamachines.com/ saves on the weight of water... I only carry 200 litres (about 45 gallons)...

 

I have not, because I tank my water out to the boat for charters and leave the tanks very empty when it's only the wife and I.

No need for a water maker.

I have, however, completely figured out my diesel/electric drive system with retractable props.

Since nothing like it exists yet, I will probably have to end the thread here and keep the information to myself for now. Thanks to everyone for the doubts and other comments.

The doubts and such are actually helpful since it helps you think through all of the possibilities of failure, etc... They have all been solved, with the exception of weight and cost. Those two could still sink it!

 

Which brought a wry smile to my face as it was the same constraint in my selection, although not so difficult as the small population base limits choice and increases some costs significantly... - Like finding propellers now

 

OK, no worries. I'll remember in future that you're only interested in taking information and not giving back anything on the topic when you see a private advantage in it.

IMO that totally contravenes the spirit of this forum but what the hell. I'll spare you my experiences in the future.

PDW

 

Pd. It's not like that. I'm happy to share the entire system, except the one part I may commercialize in the future: the retractable drives for the catamaran.

I just invented them and nothing like them exists.

I gained nothing here with respect to: generator selection, controller selection, motor selection or the design of retractable drives. It was mostly a discussion of why not to use diesel electric if you scroll back through.

 

Yes, you're right. It is a lot easier to source things where there is a large population.

Why do you need new props?

PS: I do really like Orams. I had been looking at one in duflex foam, but the cost of importation of the panels and that press thing blew the build budget as compared to just doing a female mold a-la Ian Farrier style builds.

Your boat came out beautifully. Nice job!

 

Hi CatBuilder,
The saildrive systems came with a set of folding propellers in the style of Gori... Being a power boat, and likely to remain so, as I cannot afford mast and sails etc for A$25 to $40,000, I figure replacing propellers to closer match the performance range, (from folding 2 blade 15 x 11 - - to - - 3 blade fixed at 16 x 12 - what is available, and consider trimming down the diameter if 'over-proped') - - in seeking better efficiency, as folding props are not warranted now...

Next time make it here in Australia, or, Thailand - - - staying and supervising the build is an IMPORTANT consideration)... If I built again it would be a blend of Oram & Chamberlain and built by John Hammond http://www.catchcryhamm.com/?q=node/23 and/or Niel Bowchow....

 

I agree with pd although accept you withholding the one part you mentioned as being quite reasonable. If you post details of the rest, maybe someone could even help with best price sourcing, possibly even some config ideas would be better than what you plan?

 

No problem. I'll get to posting after my infusion today.

 

Hi cat builder.
I got a lot out of the e-motion videos. They are like a lecture but very useful
Mick

 

Search on americasailingclub as the YouTube video author. I found it good

 

Ok, the system:

21-24KW, 3 phase, 240VAC Generator to run any time the engines are in use
Pair of 12KW Motor Controllers
Pair of 12KW Motors
Large 3 phase battery charger
As many batteries as makes sense in a catamaran
Large single phase 120VAC (American style) inverter to run house loads from battery bank
Possibly 240VAC to 120VAC transformer to run house loads directly from genset, but may never happen, since battery charger, though lossy, can supply large DC current from generator to battery bank, which is then inverted back to 120VAC
All required fuses and distribution panels

That's it. Very simple. Very basic. Very convenient.

 

If you are using AGM batteries, which is preferable as minimal risk of hydrogen production, they seem to be somewhat particular as to charge supply being 3 different voltages but in bulk phase as many amps as can be delivered... I also had great problems with equalising the charge currents as if in parallel and one bank showed full charge, the charge controller ignored the part charged parallel bank so complex switching had to be set up... I wish I had used single cell batteries and had one bank... Then simpler wiring and no charge current/voltage distribution problems...

 

Yes, a single bank is always better than two. It is also more efficient. I forgot to mention the batteries would be LiFePO batteries. Much higher energy densities and quick recharge rates.

 

Hi CatBuilder,
Again, charge management is VERY critical as they are usually hundreds of AA size cells in parallel and must be carefully managed internally... LiFePO4 I think is the most recent commercial iteration and several "new compounds" are in development now...

The comparative newness of this technology induced me to stay with the "Lead/Acid" technology in the 'safer' AGM packaging...