Diesel/Electric Propulsion System Design - Have your say!

I can help. Through mutual friends I understand hes totally underpowered. One however gets a different view from the articles he publishes in Aus mags.



Regards

 

Yep I know both the 44C' builders - I came close to going Torqeedo, but they are not ready yet for the bashing and beating of a cruising lifestyle, and need to put out 2 to 3 times more power (8 to 12 KW) minimum for my sized boat, and that would mean batteries holding 48V to 72V or more, and goodness only knows the Amp-Hours... - - A good concept which would improve with time and maturity... Then there is the switch-mode power controller, cabling, batteries and charger system... All tooooo complex for a cruising boat...

The present state of electric drives of 240VAC, and generators located in a more convenient place, and with better sound insulation, may be worth considering - if significant weight savings could be made - along with cost savings... Even that needs development and maturity... I will stick to diesel drive systems for the propellers and attached alternators to top up batteries, (separate engine start and house bank/s), with inverters to give an all electric galley, (I understand that some inverters can be set in parallel, to cut in as load demands), using domestic appliances - a substantial cost saving and redundancy convenience... Using either USA/Japanese 110VAC voltage/type mains power? - or that, 220/240VAC, as used by the rest of the world?...

 

Thanks for the good advice on the pods. Seems everywhere I read the same thing. They either leak water in and fail or break in some other way. Pods are out.

Yes, Masalai. I do plan on a 3 phase, 240VAC generator system, powering a pair of electric motors. The generator would be on at pretty much all times when motoring. Efficient for motoring? Not really, but acceptable for the upside of having retractable props and oodles of power for air conditioners and heaters (and cooking and hair dryers, etc...) And yes... I would use all domestic appliances to cut cost and weight.

Heat is the best example. Heating a 45' catamaran with multiple Espar units would be incredibly expensive (more than $10K) in parts, plus a complicated installation. It also weighs quite a bit once you add up all the components, more so if hydronic. Instead, I simply have a tiny ceramic heater for each stateroom at $30 each. That's $120 for my heating system and an enormous weight savings over any other method. Both use similar amounts of diesel. Also, I have to run wiring to the guest rooms anyway, so there is no added expense or weight involved in delivering the heat to the rooms. Lastly, parts for my "heating system" are available in every port. A ceramic heater breaks? Just go buy a new one.

The advantages keep going on and on and on when you start to look at an empty boat, holistically, as a set of systems. I can even get away with no solar installation if I choose, and simply conserve power greatly when charter guests aren't aboard to bring the cost of running the system down at those times.

I really thing this method will end up weighing less than if I go with a zillion different traditional systems.

One engine to maintain. The engine can be swapped out for whatever fuel we are on 20 years from now in a moment with a crane. So long as the new source of power makes electricity (fuel cells?) I can just put one of them in and hook it up and everything works off a new fuel.

And here's a BIG one my wife pointed out. All I need to run the entire boat is diesel! No more renting cars to go find propane filling stations.

Good stuff for a charter boat.

I'm going to have to do some spreadsheets this weekend and see if I can start tallying up actual wattage on appliances, amp hours, battery bank size, pricing, generator size, electric motor size and props as well as try to invent my retractable props.

 

you could talkk to http://www.sillette.co.uk they are into outdrive style legs.

20Kw electric motors ?? thats a big ask.

Overall why bother , youll get no appreciable advantages, massive costs and lots of technical headaches

Dave

 

Because I have a Masters in Physics and 20 years on the water with the last 10 in a professional capacity. The "technical headaches" aren't really headaches. They're not hard to understand if you have a grounding (pun intended) in electrical systems.

20KW was incorrect though. I had been incorrectly converting directly from 30HP diesels to 20KW electric. Wrong, wrong, wrong. The shaft HP is what matters and I didn't account for that.

I've looked at those drive legs before. Maybe they are worth another look, but I don't like how they mount. I'd like to find myself some kind of "L drive" leg to lower right under the boat - like a retractable sail drive.

 

These guys are using tried and true off the shelf components:

http://regennautic.com/

Steve

 

Im curious...as a commercial , charter boat, what do you anticipate the duty cycle of your hybrid system to be ? For instance 1000 hr per year on the diesel generator ?

 

How about non steering "stern-drive legs"? I was considering that - to mount at the aft end of the chamfer between the hulls and bridge-deck bottom, where the outboards were to go, - as right on the tail-end will present problems in a steep sea or crossing a bar (not good to loose thrust to an "airing" propeller)...
The issue then/there, is that there would be a lowered flat section to "pound"... Oh compromises, compromises & obstructions - - - I like the idea of swinging the propeller out of the water when purely sailing in peaceful quiet and harmony, but oh, - - the issues and problems ........... Lifting the propeller means sit comfortably on the boats bottom... A big plus in Melanesian and N Australian (Cyclonic season) waters...

see my boat here http://www.boatdesign.net/forums/boat-building/my-little-piece-peace-25962-114.html#post486348 and here http://www.australiawide.com/list-b...liawide&ToDo=show_details&cate=Power&de=96270

 

Hmmm... interesting question.

We tend to be on commercial charter 1/3-1/2 of the time, year round.

If we are talking hours per year, I would say something on the order of 2,880 hours to 4,320 hours. Of course, this does not mean I need full capacity for that many hours. That is just the number of hours guests are aboard and need to be *able* to use heat/ac/hair dryers, etc... A good portion of that time is sailing, they are ashore, or nice weather when nothing more than an open hatch will do.

The remaining hours of the year, we live aboard and have our own minimal needs for energy, although heat is required for an hour or two here and there to take the morning chill off. We also cook a great deal.

Designing systems for both charter needs and our liveaboard needs (at anchor) has always been a thorny issue for us. Either the charter guests get what they want and we have a good business, or we get to keep things frugal and business suffers. I have been tending to leaning toward giving the guests what they want (long hot showers, heat, air conditioning and use of hair dryers)

I am wondering where your thought process is going. Sounds like something interesting hatching... :?:

 

Weight??

Has anyone ever weighed two 30 hp electric motors, cabling etc, and a 80 hp (30 +30+losses) deisel and attached genset.

Should be fun working around 40 odd kw's in a salty marine enviroment.

Regards

 

John Gross in his Fastback catamarans devised a system whereby the legs of the engine pivoted about the spigot shaft of the gearbox, thus enabling them to be rotated at least 90 degrees, so they could be raised from the water and lowered as required, basically using what was already supplied by the manufacturer, but ingeniously leaving the attachment bolts out (as such), so the gearbox could rotate.

I am sure that there is an owner out there reading this that can supply a pic for us to see. I only saw it one day while in his yard, but it was a clever idea at the time. I guess he used a hydraulic ram to move it, not sure.

 

Hi Landie,
I don't remember that... I too would be interested in that idea - although the fastback 40's were not "interesting" for me at the time... - Did John Goss get to fly his home-made jet plane? - had enough thrust/power to go vertical ...... He used to love 'firing-it-up'...

 

Does anyone know where to find pictures and a description of this installation??

I really need to see this. No matter what path I choose, this sounds like a viable retraction scheme.

Were these saildrives he rotated up?

 

Re Drive

Surprised Sonic drive legs haven,t been mentioned , they can be lifted out of the way and are also steerable.
John Gross is a very clever man , he did fly his home built jet , built from balsa and vinylester . I was lucky enough to work with him at fastback cats for a good while , what he doesn,t know about fibreglass isn,t worth knowing .
The drive legs John made were often fabricated from the bottom end of outboards.

 

http://www.arctracer.com/boats/catamaran/catamaran-history.html
http://au.groups.yahoo.com/group/fastbackcatamarans/
http://www.multihull-maven.com/Designers/John_Gross
http://www.multihull-maven.com/Brands/Fastback

The above are some links that I googled up... Hope this helps...
I am sure his name is "Goss" but for some reason it seems to now be "GROSS" - very confusing?