Diesel Electric for a 1939 44' Elco Cruisette

Digging though the bazillion websites that mention D/E hybrid systems I cannot find anything that answers definitively if I can replace my current power configuration with comparable performance while experiencing fuel savings at the same time.

What I have is a 1939 44' Elco Cruisette, 44' 5" lwl, 11' 9" beam, displacement design, 17 net tons, 19500 dry weight. She currently has twin (gasoline) 350 cid (260 HP) direct drives and cruises at 12kts (2200rpm) with top speed of 18kts (2800rpm).

She is used for short as well as extended cruising in the near coastal waters of the Gulf of Mexico.

So many questions:

• Is it possible to get comparable performance?
• Can it be more efficient?
• Are there any examples out there?
• How do I figure for the required components?
• Where can I find such components for a "Do-It-Yourself" install?
• Can such a system be rugged, reliable, and opperate at max output for long durations?
• and many more.

What (I think) I know about D/E::?:

• DC motors are more efficient vs AC
• My current HP will have nothing to do with the electric motor HP needs
• My props and shafts will need to be replaced to take advantage of the torque range of the elect motors
• DC generators are preferred vs AC/DC conversion
• Multiple generators offer more efficiency vs single
• May be possible to achieve 50% fuel savings vs conventional power

 

It is wonderful to dream ...

But reality is very hard and ugly.

Recent diesel engines of 200-260 hp are volvo D4 and Yanmar 6BY. They have the latest common rail technology and have the lowest fuel burn.

They cost each, bare around 30 000 $. That should cost you over 100 000$ when twin installed with straigth shaft application.

If you want to go diesel electric, I think you need to add at least another 200 000 $ ( if not 500 000$) for a potential comsuption gain of 2 to 5 % (yest two to five %) compared to lastest generation diesels.
There migth be cheaper DE solutions, but expect fuel burn to increase, not to decrease.


If you want to save fuel, it would be best and cheaper to change the whole boat. Say something like this : http://www.parker-marine.com/com44page.htm . Around same length and beam of your actual boat. But around 1/3 to 1/4 of the displacement. So over 50 % Fuel saving is technically realistic. And the cost of this whole new boat, with its 2 * 125 hp diesel NOT electric engines, will be less than a hypothetical Diesel Electric refit solution for your actual one.

 

So as you explain my situation, there will been no advancement in performance/efficiency. I had my suspicions that the advantages would not out weigh the initial costs but you indicate an increase in consumption.

So after reading the technical page on the "OSSA" website their "theory" of 30%-50% improved economy, is more hype than fact? As I read their info I could never find a case example of speed in the application.

Allthough...I can see great potential for such an application in sail-drives with the ability to regenerate under sail thus having the potential to entirely eliminate the need for any combustion engine.

This concept, like my Lexus 400H (H=Hype-bred), is apparently only to give you a warm-fuzzy feeling that you're doing something green. While in-fact my hype-bred car gets the same fuel economy (23mpg combined) as the Lexus 350 in real world driving conditions making it not worth the extra $9k, and even less "green" than its' counterpart due to the additional toxic materials that will need to be dealt with at the end of their life-cycle. The best economy I have ever achieved on a full tank was 27.5mpg and that was done by driving like a granny. Heck anyone can get any car to improve its' mileage by that method.

Unless anyone else out there has a different experience with this concept I will consider this an inviable plan for the time and continue to enjoy my reliable 350s. Hopefully technology and costs will improve over time...sure sounds like a good idea.

 

The old Elco's are beautiful boats, and and probably more efficient operating in displacement mode than most more modern hulls. That said, I'm afraid that from an economic standpoint, your best option is to just go slower with the power plants you have now.

The kind of hybrid drive you're talking about would be of dubious value in reducing fuel burn anyway, but would certainly cost more than ever could be recouped.

If your gasser Chevys are running good, keep running them, just maybe a little slower. I would recommend that you use some of your engine time this summer doing fuel consumption tests with a graduated supply and a GPS. Chart your results to find the Elco's "happy" speed.

Someday when your SBC's are getting tired you can think about replacing them with diesels, but with the current price of fuel oil relative to gas, I wouldn't be in any hurry

moT

 

If you do decide to replace them first get all the info as suggested above. And use the fuel consumption to decide how to repower .

IF you will accept that 12k as normal cruise , knowing that Fuel Flow is critical.
roughly 10hp is produced from a gal of gas.
A non electronic ex truck engine will roughly give 17 or 18hp from a gal of diesel.

So if 8gph per engine(80hp) is the gasser burn at 12K a 100 to 120 rated hp diesel will be the least expensive choice.

With proper transmission ratio selection you can keep the current props and shafts.
And a 5gph fuel burn may be easier to live with.

FF