Article on converting 43-footer to diesel-electric propulsion

[lockhughes]

Thought this was a beautiful description by one boater, about his experiences re-powering with diesel-electric propulsion in his 43-foot 1998 Cruisers Yachts 3870 Esprit... Concise comparative on the relative merits vs diesel/gas

http://www.feys.org/CaptainLog/log.htm

(No, I don't have any relationship to his business!)
Lock

[Polarity]

Hi Lock
You really got me thinking about this diesel electric thing. One thing I do know however is that my budget won't stretch to an ewheel motor. Any ideas of what else might be on the market that could be obtained inexpensively and modified by a reasonably capable engineer (ie me!). After all there are lots of electric motors kicking around for a million applications... some of them might even be in a "relace it, needed or not" application...
Ideas anyone?

Cheers

Paul

[lockhughes]

Originally posted by Polarity
Any ideas of what else might be on the market that could be obtained inexpensively and modified by a reasonably capable engineer (ie me!). After all there are lots of electric motors kicking around for a million applications... some of them might even be in a "relace it, needed or not" application...
Ideas anyone?
Paul

Hopped on eBay a couple of days ago. A Search for "electric motor" turned up something like 300+ entries. 95% looked useless, but some looked interesting... based on xxHP and prices.

Personally, I would be only interested in non-brushes and commutators... used to sell lots of brushes and rebuilds in a past life. Big believer in minimal parts. Also like strength of rare earth magnets. At least would only consider motors engineered for EVs. Just trying to keep things simple in my ignorance<smile>

These guys have been getting some favourable "press" in the Yahoo electric boats group recently:

http://www.evparts.com

Cheers

Lock

look at fast electric yacht systems located in texas. while not cheap i'm sure, they are on the cutting edge of this tecnology. recently installed their system on the hms bounty(approx 400 ton displacement) with a 350 cummins diesel powering twin electric screws (54"). i haven't heard anything about efficiency. feys has systems for any size boat.

[gonzo]

I worked on ocean going tugs with this kind of propulsion. We worked doing suveys. The reason to choose this system is the precision in the speed adjustment. I don't know if the extra price is justified in other applications.

checkout Passagemaker May/June 2003 issue- There is a great article(lengthy) about these guys from Texas

[Peter_T]

Tugs went diesel electric when SCR system was dominating in the offshore sector in controlling power for a series of power movers.
The main engines, shaftings, gear boxes were replaced by electric motors at the tail shaft input position. The power of the direct drive main engines is subdivided into serveral generators. It is likely to make a common size with the service generators. One extra generator is usually included, together will provide power for the peak load. During service, the propulsion power will be always available on demand. One generator or two will be offline for maintainence. The motor driving the propeller with AC using the SCR conversion media, switching from AC to DC filtering all the pulsation electronically and then, converts back to AC. This system enable the use of standard AC motors which are cheaper.

In Europe, they use cyclo convertor to take AC power, subdivide into elements, normalizing the power elements to uniform sine curve format, then regroup them for power delivery to the AC motor. This system is sometimes preceeded with the SCR system for perfection in power management. Such a system is expensive but will ensure smooth running of the power movers.

For small crafts and yachts. It will depend if the vessel has enough machinery and power outlets to justify a complex system with electronics. I wondered if the SCR and the Convertor group have developed a mini series for adoption to yachts, otherwise, the standard ship set will be used.

The SCR / convertor system will deliver electrical power to the precise spectrum at varies rpm rating to power the propeller in fixed pitch style. Reversing is as easy as switching rpm from one direction to another after a neutral stop. So the control is better. It is also possible to adopt CP or VP propellers, but has been considered optional at the owners choice.

Lets take a large yacht. You have propulsion system, steering system, bilge/ballast/fire-fighting system, large capacity air conditioning load, mooring / anchor handling system, cooking and pantry power, laundry, entertainment facility power, lighting, communication and navigation. It seems that a SCR system can be adopted to take all the generator power and regulates the power supply/usage.

For a lesser equipped small vessel, going electric is best in the DC method with batteries and a charging system. For medium size yacht, select DC motor systems, try means to convert generated power to DC. The electrical engineer will figure out the system.

Apart from better control and quietness, this SCR/convertor system can satisfy the emission standard in a better way. Spare parts for common generators makes machinery maintainence easy.

The future is diesel electric or gas-turbine electric. Electrical voltage will step to high frequency power. This sector is rapidly changing in Europe.

Peter

[gonzo]

What are the advantages of higher frquency? I understand that the impedance increases, but the RMS power decreases too.

[Peter_T]

http://www.asc2002.com/summaries/f/FP-03.pdf
http://www.ship-technology.com/contr.../scandinavian/

Supply boats with SCR/convertor system use high voltage to reduce the cable size. High frequency is common on high capacity winches marketing in parallel with high pressure hydraulic winches. This is for compact design and conductivity. Some use a combination of high frequency, high voltage with high pressure hydraulic to conserve building material.

Peter

[gonzo]

Thanks, I guess it'll take some studying. This is the best part of the forum.

[ted655]

Check out the Vetus website. They have one for smaller boats

Has anyone hear any more from FEYS.org? I've tried to contact them but have never received a response. They had put together the Siemens ELFA motors/controllers from European bus systems into a boat system in Texas last year.

[coyotecoast]

I Read recently on the Navy Experimenting with HTS (High-Temperature Superconductors) Electric Motors eliminating the 10-15% percent loss that may be experienced on some systems, I am working on an old 180 WLB bouy tender with Diesel Electric Propulsion, using two EMD 645 providing the Juice to a 1200 HP GE Direct Current motor.

Mike McVeigh
Coyote Coast Marine

[MikeJohns]

Originally Posted by Polarity

Hi Lock
You really got me thinking about this diesel electric thing. One thing I do know however is that my budget won't stretch to an ewheel motor. Any ideas of what else might be on the market that could be obtained inexpensively and modified by a reasonably capable engineer (ie me!). After all there are lots of electric motors kicking around for a million applications... some of them might even be in a "relace it, needed or not" application...
Ideas anyone?

Cheers

Paul

Polarity

How about a marine conversion of one of the automotive electric vehicles. Europes crawling with them now. You can have a battery bank and a big Genset. Lots of solar panels, Wind generators. Probably get an hour a day motoring directly to windward for free !!

Cheers