Diesel Electric Propulsion

CaptJ,

I've used the 36 hp Yanmar outboard before, tough little unit but way too noisy. A pair of the 27 hp units were used on a 35' multihull from SF to Hawaii, burned 385 gallons for 2250 nm.

So, about 6mpg. Well, the only way I see how your going to make the electric work and get range you're looking for, is to maximize whatever charging you can with solar panels and wind generation. Another idea are 2 diesel outboards, supplemented by diesel electric. When you run out of electricity, you can switch over to the small diesel outboards and they can also help charge the batteries (albeit slightly) while they're running in addition to the solar panels and wind generation so that you can shut them off and switch back over to electric. I'm no expert in this field, but I don't believe the technology is there to get 15 mpg in a typical boat design at this point in time without relying on sail. Someone made a hybrid boat that was nicely finished off, around 30-35' that was electric and the entire hardtop was built in solar panels. Anyone remember who made it?

That vessel displaced 3 times as much as my planned boat and as you crunched the numbers got close to 6 nm per gallon running at twice the cruise speed as I plan to. I will have a small amount of solar assist. Now does 15 nm per gallon seem so far fetched?

I saw one of those boats in St Michaels MD recently.
I didn't get near enough to scruntinize it though.
It was a nice enough looking thing.

I had gone to the web site when they first came out a year or so ago.
The electric side of the system gave you about 6 knots for a pretty short period of time and 6 knots was WOT for MAYBE 30 minutes.

There was a 6 cylinder ( cummins maybe ?) diesel and the entire hard top was a photo-voltaic panel(s).

I thought that it was a nice boat but 6 knots for 30 minutes or less was sorta dissappointing.

Found it.

Greenline Hybrid dot com

From the web site:
" The hulls are outstandingly efficient throughout their speed range, bringing unbeatable mileage and range of over 700 nautical miles at a speed of 7 knots. This, combined with a top speed up to 15 knots, makes long day trips a breeze. The electric drive mode will not only allow for cruising in complete silence at speeds of up to 6 knots, but also offer a range of up to 20 nautical miles, before the diesel motor is required."

This one crossed the Atlantic using a heavy catamaran ferry hull on 10 kw of solar running 5.5 kt avarage.
transatlantic21: The world's first crossing of the Atlantic on a solar boat

This solar cat was purpose built and has logged 8000 nm on 8 kw of solar.
Boat - SolarWave

This one is Reuban Trane's, 6 kw of solar, upgrade to Winston LiFePO4 cells, but not pure solar, it is diesel electric solar.
Island Pilot DSe Home Page

I want to thank you for posting this link. I'm reading that 1st edition cover to cover. It spells out the future of diesel electric marine transportation. I haven't read a 1st edition of a magazine cover to cover since Multihulls came out in the mid 70's. Had no idea how many big players are in this field along with LiFePO4 battery companies.

As an early adopter to LiFePO4 batteries, I discovered on my own the 2 to 1 relationship of usable energy storage of these lithium batteries vs lead acid, but a advertiser in this magazine coined a new ahr term and it has that 2 to 1 ratio. When you consider all aspects such as 80% DOD vs 50 % DOD for lead acid, very low Peukert effect, almost nil voltage sag under heavy load, it does prove that 200 ahr of LiFePO4 will offer the same usable capacity of 400 ahr of lead.

Thanks for the links. I am very interested in this technology.

In my mind something like this is a good idea. Island Pilot DSe Home Page It is a combination solar diesel hybrid.

Pure solar has been done and circumnavigated the world PlanetSolar. Way too expensive and inefficient. I think a DE setup that is augmented with solar and/or wind is the way to go. The soar/wind can more than make up for any inefficiencies in the DE setup.

Imagine a large catamaran like the one that went around the world on only solar but remove 90% of the batteries and put in one or more diesel generators. For maybe 5+ hrs a day all propulsion can come from solar and if you need to move at night you use the generator. Plus the solar will supply all the power for house loads while anchored.

This type of setup could offer huge savings in diesel while still allowing the boat to be used as a boat. The diesel usage could be virtually zero if you only choose to travel when the sun is up.

milo12,

If your interested in the Island Pilot DSe, and it appears non members can post on this forum, I'll give Reuban a link here.

Uhhhhhh yeah. NO. It says the electric cruising speed is 4 knots (which is how I'd imagine they get 20NM range out of it), max speed is 6 knots under electric. However you can go with the smallest engines and get a 10 knot cruise speed with a great range.....but you're giving up too much......I don't see it being very practical for many boaters to be interested.....

Uhhhhhh yeah. NO. It says the electric cruising speed is 4 knots (which is how I'd imagine they get 20NM range out of it), max speed is 6 knots under electric. However you can go with the smallest engines and get a 10 knot cruise speed with a great range.....but you're giving up too much......I don't see it being very practical for many boaters to be interested.....

I remember this buddy of mine bought this $100 solar/wind up stereo (portable) for me when it first came out thinking it was a great invention.....welllllll......the only time it would play music without the volume going up and down and up and down was if it was direct direct sunlight, anything less than that and the volume would cut in and out......then we tried the handcrank method.....well that played at the normal volume for about 2 songs......but you had to crank the hell out of the thing........like for 3 minutes.....needless to say.....on the second boat ride HE ended up throwing it overboard.....LOLOLOL

As an esteemed member suggested earlier: "Don't stop believing!"

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I'm going to throw my 2 cents in here. Several years ago, I had a very long conversation on the stern of a Doggersbank, with Dick Boon, who basically wrote the book on DE propulsion for smaller boats. He pretty much sold me on the concept. Problem is it's still very expensive, and will never return the original investment. My builders rep for my new build keeps harping on resale. He has a valid point, but to this day maintains that DE is still too expensive, and I'll never see that money again when it comes time to put it on the secondary market. Also the hull I'm using is a semi-displacement and pods couldn't achieve the top end of the boat....too much parasitic drag.

I hope that I live long enough to see DE propulsion along with azimuthing drives are the norm on displacement/semi displacement boats. There was an article last month on this subject in Passage Maker, although time hasn't permitted me to read it yet. I enjoyed reading this thread...there's a bunch of really talented people on this Forum!

Rim Drive Props

I hope to see this development as well. One current impediment might be the lesser funds available for yachting subjects in the current world economy of boating.

I'm really hopeful to see more 'shaft-less' developments such as these rim-drive props arrangements.
http://www.yachtforums.com/forums/technical-discussion/3961-rim-driven-propellers-4.html

RIM drives

industrial RIM drives:

Voith | Voith Inline Thruster / Voith Inline Propeller

Hi Ju52... I've checked out Voith, but their applications far exceed the parameters for a boat my size....she's just a 105 footer. I love their bow thrusters, but I'd have to build a 400 foot yacht to accommodate their equipment.

Hi,

Something around 1/2 that would work just fine - They already are out there.

Yes my friend...but alas my budget doesn't include that length of a boat. I'm just a working class stiff.

the TRUSTERS are developed, ....but I don't get the impression that the continuous duty propulsion units are fully developed.