Hybrid Electric Conversion for a Cat

[jdisarro]

I am looking for advice about the purchase of a cat, I was thinking of buying a lagoon 380 cheap coming out of charter the systems will all need upgrading. Since I will have to spend some coin, I was wondering if it would not be the perfect opportunity to convert the whole yacht to a 144 V electric propulsion system, install a watermaker, solar, and wind generators as well as a gen set and air conditioning. That way I would know that all the systems are new amd I won't have problems while cruising and living aboard the next three years. I don't know how much this refit would cost for one thing. The other question is: would there be a market and a buyer for an electric boat after we finish with her. I would Have about $ 50,000-65,000. to spend on a refit like this or I would just have to purchase a more expensive better maintained vessel and just stay with the industry standard vessel.

Any advise is greatly appreciated.

[Pblais]

I was wondering if it would not be the perfect opportunity to convert the whole yacht to a 144 V electric propulsion system, install a watermaker, solar, and wind generators as well as a gen set and air conditioning.

It might if you didn't expect it to work or pay for itself. You really need max solar and a serious genset to make this fly for a cruiser. After you finish it there is no way you could sell it in this market to anyone that understood what they were buying and not lose money is a large way.

You really need to know everything before you try something like this and if you don't really want to own it you are going the wrong way. For the money buy a boat you want to keep it and forget everything else. There is scant money buying and spending that much money to expect to recover even some of it. The boat builders of today are smarter than you are and they are not doing it. There is no serious market.

[jdisarro]

Thanks Paul Good advice.

[Rhapsody-NS27]

I was looking into electric motors while looking for my first boat. It's interesting that some of the systems out there also allow you to regenerate power back to the batteries if you're doing a lot of sailing. I saw a video on YouTube where a Cat was used as charter in BVI (i think) that was electric and said it worked great. Since a lot of people don't know the electric motors very well, they might not take the chance of buying. It sounds like a fun project to me.

[catty]

Its still early days for reliable electric motor technology for yachts. Fitting a 144 volt dc device in the bilge of a vessel operating in salt water not only sounds dangerous but very expensive when the bilges get wet.

Regards

[Juniper]

The motors are the reliable part, these are/should be the same motors used for car conversions, they sit under a car going through road salt spray in the winter, if you have Calcium cloride spray in your engine bay your boat needs help,
The controllers, chargers, batteries, and everything else will be the headache.
Think about it, you have an electric motor in there now, aka starter,

[Rhapsody-NS27]

Originally Posted by catty

Its still early days for reliable electric motor technology for yachts.

Perhaps why I've only seen relatively little info on them. There's some blogs of people doing the conversion and a few companies out there. I've only found a few myself, but sure there are more I haven't found yet. I thought it would be kind of a fun project to get something like 25'-30' boat to do the conversion.

I'm still looking around, doing homework.

[catty]

Originally Posted by Juniper

The motors are the reliable part, these are/should be the same motors used for car conversions, they sit under a car going through road salt spray in the winter, if you have Calcium cloride spray in your engine bay your boat needs help,
The controllers, chargers, batteries, and everything else will be the headache.
Think about it, you have an electric motor in there now, aka starter,

Yes, on first thoughts it sounds like a great idea.

Although with twin diesels you do have redundancy. With dry bilges, like yourself, not a problem. I'm not sure the electric starter is the most reliable part of a diesel engine, and a 15 or 20 hp electric motor is probably a little more expensive than your average starter. 144v dc at around 100 amps in a boat bilge quite frankly scares me when things go wrong.( not a problem if you are paying someone else to play with it).
Think about it.

[Sand crab]

My advice, DONT DO IT. Check out this cat for sale that went through 3 versions with a recommendation on a fourth.
1992 Fioleau FIOLLEAU - CRUISING CAT - Boats.com

Now much money do you think they spent, wasted?

[roverhi]

Since you are getting all this positve hype on electric propulsion let me add some more. About six months ago, a person was trying to sell the electric propulsion system that he'd torn out of his catamaran. Asking price for the two year old electric propulsion was less than 10% of its new cost. Must have worked really well for him to take such a bath switching over to diesel.

[daddle]

Originally Posted by jdisarro

...That way I would know that all the systems are new and I won't have problems...

Heh! Funny

Diesel-electric propulsion is heavy and inefficient. Great for locomotives, bad for catamarans.

[Juniper]

Originally Posted by catty

Yes, on first thoughts it sounds like a great idea.

Although with twin diesels you do have redundancy. With dry bilges, like yourself, not a problem. I'm not sure the electric starter is the most reliable part of a diesel engine, and a 15 or 20 hp electric motor is probably a little more expensive than your average starter. 144v dc at around 100 amps in a boat bilge quite frankly scares me when things go wrong.( not a problem if you are paying someone else to play with it).
Think about it.

I'm just saying the motors will be the least of the problems, at least if they are inside the hull, now pod mount mootors? As to cost a 20 HP DC motor is less then $2000, AC less, and weighs about 100Lbs, AC more, batteries to run it for any time will add up fast, the controlers, fuses, wires, safeties, and all else will cost quite a bit too.

For a cat unless it is heavy to start with the batteries will be the hardest the to deal with, and it all depends on how it is used, If all the motor is used for is to get of the dock, it may well work, if you intend to motor for days on end, diesel is better.

[Adelie]

Using an engine to generate electricity then to store it in a battery costs about 15% of the power coming out of the engine. Getting it back out of the battery and running a motor costs another 15% of the power (let's say 70% of the energy is available, the short term horsepower may be unchanged depending on the motors used.)

An engine that drives the prop directly looses 3-10% depending on the number and type of items in the drive train: transmission v-drive, sail-drive and C-V joints.

For a boat that is just going to be day-sailed where the only need it to get in and out of the marina and to cruise along at a slow to moderate speed for a short to moderate distance (10-50nm) an electric system works reasonably. The batteries can be charged over long periods using solar panels or for a moderate price shore power can be used. Moderate speeds and ranges can be obtained by using a small genset.

Longer ranges become problematical because the efficiency loss means significantly more fuel needs to be taken along. Also, to get the same total horsepower at the prop for long distances, the total installation weight increases a lot: the genset needs to be significantly larger than the original engines to compensate for the efficiency loss and there is increased fuel tankage, the batteries are added on top of this plus the weight of the electric motors.

For a cat there is a 3rd option. Leave one engine installed in one hull with an extra large alternator or 2, add a small trolling motor on that side, and replace the engine in the other hull with batteries and an electric drive motor. For maneuvering in the marina the trolling motor and electric motor can get the boat out in calm and moderate conditions using only battery power. In heavier conditions the engine and motor will do the job.

I do not have first hand experience but I have read in various sources that many cat sailors will motor on one engine for long distances for efficiency and engine wear reasons and the asymmetric thrust is balanced by constant rudder pressure. Leaving one engine in place would allow you to use this tactic to optimize long distance fuel efficiency.

The only drawback is that you would not be able to generate full thrust and speed on both sides except for short periods or distances, say long enough to get thru a reef pass against a big current (6kt) but not enough to run up a river long distances against a similar flow or to motor upwind against heavy seas for a long distance.

If you can live with the limits on duration of max thrust you can have the benefits of an electric system and a normal engine installation without a big weight penalty.

[Sand crab]

This topic came up a while back. As I said previously the laws of physics dictate that there is no such thing as a free lunch. In other words using fuel to create energy to produce electricity to propel the boat is less efficient than just using the fuel to create energy to propel the boat. The energy loss is almost always as heat. Please note that most of those hybrid Lagoon 420s have now been converted to standard propulsion at a huge expense. Given these facts I have 2 questions.
1. Why do locomotives use diesel electric motors?
2. Why do these electric yacht motors have such wimpy horsepower ratings like 10 HP. Is it because they have alot of torque as compensation or are they just wimpy motors?

[mbianka]

Converted my 8 ton 30 foot monohull sailboat to electric propulsion in 2008 and never looked back using an ASMO Marine Thoosa 9000.
THE BIANKA LOG BLOG: Going electric: Part 1: The why and how
Maintenance cost have been just about nil. Used seven gallons of gas last year including the dingy outboard worked out to about 50 nm per gallon. I can go 5knts + but of course not for long. I can however do three knots as long as the fuel lasts without touching the battery bank. I use solar and wind turbine along with a small generator for most of my charging which is at a mooring or anchor. Regen has not been that successful on mine and most mono hulls but, works better on cats from what I have observed. Still I don't really see the need for it. Nice feature of EP is electro sailing i.e. just turning the prop enough to negate the prop drag when sailing and it does so quietly. I for one would never go back to having a diesel.