Electic Motor for propulsion

[Hankthelank]

Good day all,

Looking for a little advice. Currently I am fixing up a 8.7m Columbia, with the hopes of taking a year off and sailing in through the Caribbean and beyond. The boat has an atomic 4 engine which I am not thrilled about. The way I would like to go is to remove the atomic 4 and replace it with an electric motor and 400 pounds worth of gel batteries. Get a couple of solar panels, wind turbine and make this boat all renewable. Get ride of fuel as much as possible. I figure that at the worst I would need a portable gas generator to charge the batteries when I need to motor a significant distance(greater then 30nautical miles). My problem now is, is it worth the cost. To replace the propulsion system, it's going to cost me around 10k, the same cost as switching to diesel. This is more then I paid for the boat! Does anybody have any experience with this system? How about with the 8.7m columbia as a cruising sailboat? The good thing about this type of propulsion system is that it can be relatively easy to remove, so at a later date, if I want to upgrade my boat, I can look for a boat with a dead engine and switch over the propulsion system. does anybody have any advice on this idea?

[Pblais]

The way I would like to go is to remove the atomic 4 and replace it with an electric motor and 400 pounds worth of gel batteries.

We have a thread or multiple threads about a Cat rigged with electric motors. Check out the Fastcat threads. At worst it is very interesting reading and you can see some of the issues spelled out for a Cat design. At best you learn something about a cool topic.

Off hand 400 pounds of batteries is not enough. I think the cat was using 10 or more group 4 batteries so that would about double the weight. I'm not sure your 8.7 meter boat is up for that much battery tonnage and of course your wallet. The batteries alone are maybe more than you think. Concorde group 4 AGM Lifelines (135 lbs.) were running a hideous $700 each last I checked. Batteries have more than doubled in price over the last 4 years.

It also brings up the ugly side of the problem too. Charging a big bunch of batteries from a wind gen and solar panneals is a huge job and you can't come close to enough area for solar panels. A large cat barely adds large amounts and then not 100%. You can't add enough solar to power the fridge as it is with no electric engine. You'll require genset to charge the batteries so you'll still need a fuel tank too.

I really don't see this as a low cost alternative. It's going to be very expensive and you won't have any room for beer. Repowering to a small deisel would be cheaper and easier. Keeping the Atomic 4 isn't the worst idea. There is a cult of folks still running them. You learn to properly deal with gasoline or you blow up.

[mikereed100]

Originally Posted by Pblais

We have a thread or multiple threads about a Cat rigged with electric motors. Check out the Fastcat threads. At worst it is very interesting reading and you can see some of the issues spelled out for a Cat design. At best you learn something about a cool topic.

Off hand 400 pounds of batteries is not enough. I think the cat was using 10 or more group 4 batteries so that would about double the weight. I'm not sure your 8.7 meter boat is up for that much battery tonnage and of course your wallet. The batteries alone are maybe more than you think. Concorde group 4 AGM Lifelines (135 lbs.) were running a hideous $700 each last I checked. Batteries have more than doubled in price over the last 4 years.

It also brings up the ugly side of the problem too. Charging a big bunch of batteries from a wind gen and solar panneals is a huge job and you can't come close to enough area for solar panels. A large cat barely adds large amounts and then not 100%. You can't add enough solar to power the fridge as it is with no electric engine. You'll require genset to charge the batteries so you'll still need a fuel tank too.

I really don't see this as a low cost alternative. It's going to be very expensive and you won't have any room for beer. Repowering to a small deisel would be cheaper and easier. Keeping the Atomic 4 isn't the worst idea. There is a cult of folks still running them. You learn to properly deal with gasoline or you blow up.

What Paul said.
Another great resource is the yahoo electric boat group.
I considered switching to electric when I thought my atomic 4 had gone TU but unless you have a large (expensive) generator you will not be able to motor more than a few miles at speed. The atomic 4 is a great motor. Quieter, smoother and more powerfull than a similarly sized diesel. If you are not cruising to my mind it is preferable but I am one of the cult Paul is talking about. (join us.....beee one of us....)

Mike

[henryv]

It has been done - check out link: Electric Yacht - Tranquility, Columbia 29

[Morgan Paul]

Keeping the Atomic 4 isn't the worst idea. There is a cult of folks still running them. You learn to properly deal with gasoline or you blow up.

I think this is your best bet if it is in halfway decent shape. I have one in my 1973 Morgan 36T. It runs and it is a simple machine.

[Hankthelank]

thanks for the advice guys. One of my other concerns is the price of fuel. With the state that the world is now in, i'm afraid that fuel is going to hit the roof. Hopefully its at it's peak and will come down, but anythings possible with these crazies in power and the nutbars that pull their strings. I've calculated that with 250ah, 48v battery bank, i could motor for about 30nm. Anyhow thanks again for your advice, this is a great website, my work productivity has taken a hit since I stubbled across this site!!

[SeaKing]

Hankthelank, check this website also if you haven't found it.

RE-E-POWER Electric Propulsion for Marine Applications

[Pblais]

Once you do the numbers for Electric Yacht you quickly find this isn't for cruising or even touring. The Duffy electric boat comes to mind as well. If your range is only a few hours on flat water then it works and very well too. In and out of the slip for day sailing might be a perfect match and cheaper than a big engine you run for 10 minutes in and out.

For cruising I would want ranges in the 80 plus hours time span and that is over and above a total capacity of 400 amp hours for the rest of the boat electrical needs. Without an engine/alternator based charging source I would need to rework all these number higher yet for some margin of safety. There is just no solar / wind system that can spit that much lightning that you can attach to a reasonable sized boat. On a small boat (say 40ft) making the non engine systems self sufficient is very difficult. With more than 2 people aboard the numbers become impossible.

If you look at the Fastcat system I think they come as close as possible today for a cruising boat run on electric. It also uses a diesel genset too. Gideon is really engineering toward a real working solution not just speculating. Using solar power to power sails with wind is still better than making electricity.

[clausont]

The boat next to ours in Winchester Bay, Oregon is a Columbia 8.7 with an electric propulsion system in it. I will try to get you in contact with the owner.

[Hankthelank]

Originally Posted by clausont

The boat next to ours in Winchester Bay, Oregon is a Columbia 8.7 with an electric propulsion system in it. I will try to get you in contact with the owner.

That would be great! thanks clausont!