Info on math of electric boat?

[Jdege]

It's a Palmer P/60.

If I go for this boat, I'd certainly look into what it would take to get it working. If $50 for new points would get it running, I'd probably go with that, at least for a few years. (It's an old boat, there will be plenty of things that need to be fixed. )

OTOH, even with new points it'd still be a fifty- year- old engine that hasn't had a rebuild in living memory.

My options:

* Rebuild the gas engine
* Replace with a diesel
* Replace with a commercial electric
* Replace with a DIY electric

For the first three it's just ask for a price.

It's the last choice for which I need research.

[Adelie]

Rebuild would be $2-5k
Repower $9-15k
Commercial conversion ?
DIY conversion $4-8k

[roland stockham]

As far as electric goes, in the current state of thing the cost of batteries makes it impractical unless you can live with only having enough power to get in and out of harbour in flat water with no wind. Cats may be different in areas with good solar. This is however a rapidly developing technology so if there is a option for something temp for 2 or 3 years things may have changed.

[Volkeno]

If the gas engine could be fixed cheaply, I would fix it and sell it to one of the gas lovers.
The electric set up is going to depend on what you want to do with it. Mostly it's going to be the battery bank size that will drive price.
There are different motors from high end to $100 forklift motors that will work.
If you just want to use the motor to get in and out of the harbor, a small set of batteries will give you the energy and you can recharge at the dock, or by getting a motor that can act as a generator while you sail (if you go fast enough).
If you are cruising, you will want to identify places for batteries and think about how much solar you can carry. As panels get more efficient, it should be easier to keep the batteries charged. Newer controllers can reduce losses to shading.
I have been thinking about converting to electric and following several youtube channels like Sailing Uma, where they converted a 35' Pearson I think and originally used FLA batteries until they melted them. They replaced with Lithium and seem pretty happy with about a 25 mile range under power. They do their own work, so they save a lot of money.

[TrentePieds]

As a rule of thumb:

Case #1: For motoring in and out of harbour only: 2HP per ton displacement, so in your case, 12 - 15HP.

Case #2: For motoring SOME distance, say 10 - 30 NM in benign, predominantly flat water without significant tidal flows and without enuff wind to sail efficiently: 3HP per ton displacement, so in your case, 20 -25 HP,

Case #3: For motoring in significantly adverse conditions, i.e. on a tight, inflexible schedule, against hard blows, in choppy waters, and/or waters with significant currents: 4HP per ton displacement, so in your case 25 -35 HP.

I am a "Case 3" with a displacement of 5 1/2 tons. I have 20HP. It's sufficient, but only just, because I'm retired and have time to wait out the tides when that's the smart thing to do, and because I would rather drink beer than struggle through 30 knots of wind and a short sea.

As others have said: Nothing wrong with the Atomic4. If you are worried about a set of points, you would serve yourself well by learning to do simple engine maintenance and repair before you contemplate going to sea.

At the present state of development of electric propulsion it is viable for "Case #1" only, and then only just. The weak component of EP is battery capacity, and all the hype notwithstanding we have reached, I believe, the point of diminishing returns in the development of battery technology. In consequence, if operating in Case #2 or Case #3 conditions is in your "immediate" future - looking, say, 30 years out - you will serve yourself far better by repairing what you have, and when the gas pot dies, by going to a diesel. If you do that the approximate cost of installing 20HP (brand new, professional installation) would be about US$12K. The engine itself, about US$8K. If you are worried about points in your gas pot you should probably not attempt to perform an engine swap yourself.

All the best
TrentePieds

[Adelie]

For Palmer parts, apparently http://boatcityyachts.com/palmer%206...ne%20parts.htm is the place.

For DIY conversion check out http://ddmotorsystems.com/ElectricBoats.php which primarily does golf carts but does boat stuff too.

[fred4936]

I put an electric system in my Tartan 27-2 about 6 years ago. I am very happy with it. It has been reliable, economical, smooth, and quiet, although there is a bearing noise. We only use it for getting in and out of the creek the boat stays at. We only ran out of juice once, and that was last year; too much of a headwind. As far as numbers go, the conversion cost me under $4k. I have about 4 hours of range, cruising speed around 4.5 kts. This is not enough for many, but for us it has worked out well.

[svJasmine]

it all has to do with the intended use of the vessel. I use an electric motor on my Bristol 19 behind my house on a canal on a lake. I plug it in after every sail.


On my Westsail 32 kept in florida, I wouldn't have electric. It won't allow me to enjoy the keys and Bahamas. Besides, if I tried, I couldn't afford the nightly marinas.

[SteveSails]

I had a P60, always started and ran fine, but that was 40 years ago. Most P60s are sea water cooled so likely to rust out before wear out. I'll second boatcityyachts.com for parts.

A new diesel would be the most cost effective when you consider performance, range, maintenance and resale. Beta Marine would be my choice.

Here are two suppliers of electric systems https://oceanvolt.com and https://www.elcomotoryachts.com

Ocean Volt has modular motors of 10KW each, you can build up to a 40KW motor with 4 units. Interesting concept.

Elco has motors from 6HP up to beyond what you need as well as electric outboards. They also have pricing on the website.

DIY can be done if you have the talent, tools and time but resale value will be lower than a commercial system even if your system is better. A new diesel would have the highest resale value.

Electric drive is almost maintenance free but the cost of replacing batteries after 5 - 8 years will negate any savings on maintenance.

Good luck

[Brewgyver]

Originally Posted by Jdege

(snippage)
My options:

* Rebuild the gas engine
* Replace with a diesel
* Replace with a commercial electric
* Replace with a DIY electric

Jdege,

You DO have another option, one that would be simple, reliable, and less expensive than any of the four above mentioned. Install a lifting outboard motor mount on the stern, and hang a 9.9 to 15 hp motor on it, preferably electric start. I know three Catalina 30s just in my part of my marina that are powered that way, and it's very similar to the Chance in power requirements.

You never did state your expected use, but if it's much more than getting in and out of your marina or mooring, you really can forget the electric options.
You should also consider how long you plan to own the boat, as putting the equivalent of the $ value of the boat (or more) into it with just about any inboard repower doesn't make a whole lot of sense.

I bought my '78 C30 six years ago, the A4 in it is still running quite well. So if you must have an inboard, I'd suggest adding another option of finding a good deal on an A$ to replace the Palmer.

Or keep looking at boats, which is frequently the best option in such cases.

[Chotu]

Electric Boat Math:

Case: Diesel to electricity to propulsion

Diesel energy -engine losses -electrical conversion losses -converting back to kinetic energy < Diesel energy -engine losses

Case: Regeneration

Sailing kinetic energy -dragging a turbine -converting kinetic energy to electric -loss during battery charging -converting stored electricity back to kinetic < Just Sailing

[Adelie]

And your point is Chotu?

[Chotu]

Originally Posted by Adelie

And your point is Chotu?

The thread asked for the math. That's the math governing all electric marine propulsion systems.

Q.E.D.

PS: Note the greater than and less than symbols. These show greater and less energy.

[roverhi]

BoatUS magazine has an article on some guys who converted a sailboat to electric. They did all the work themselves and sourced almost everything from non Marine rated parts. They bought a trashed '85 Hunter 31m for $4,000, used a golf cart motor of supposedly the same hp to the 16hp diesel they tore out. Added 8 260 amp batteries, 5 solar panels that look to be about 130 watt output and the various charge controllers, Heavy wiring, and monitors. Total cost with them doing all the work was around $8,000 not counting donations which reduced the installation cost considerably.

The huge battery capacity gives a 60 mile cruising range at 3.5 knots in no wind/sea conditions. Range could be more than halved going faster or fighting wind and sea. The solar panels obstruct the walkways forward plus a huge solar panel awning. Amazingly the article leaves out the recharge time using solar as only power source. Would be willing to bet it would days to fully recharge depleted batteries using the solar only. That would give them a possible cruising range of less than a 100 miles a week. On their trip south used marinas AC to recharge the batteries.

Even with large battery capacity, ssssllllooowww cruising speed, and using shore power to recharge the batteries range was minimal. My conclusion is electric power is great if you aren't going anywhere.

With the help of Moyer Marine you can keep an A4 going practically forever. They use significantly more fuel and will take more routine maintenance than a diesel but they are way quieter and smoother than any diesel I've owned. Not unusual to not even be aware the A4 is running in a well done installation.

[Jdege]

I've not stated intended use because I don't have plans, at this point, only vague intentions. I'm living in Minneapolis, intending to retire to a liveaboard along the Gulf and Atlantic coasts and the islands.

Retirement is a few years away, yet, but I've been looking at boats around here and in Superior and Michigan. Keeping it in Green Bay or Duluth, or bringing it here and sailing Lake St Croix or Pepin.

Fixing what needs to be fixed for fresh water sailing.

Then, come retirement, taking it down to Mobile and putting on salt water bottom paint, etc.

So, I've found what might be a good boat, given some work.

And I'm thinking about options.

Would electric work?

For getting in and out of harbor for lake day sailing? Yes.

For taking the rivers and the ditch from Minneapolis to Mobile? Not a chance.

Making decisions eliminates options.

But it also owns up opportunities.

Balancing the two is something only I can do. And i could do it better were i less ignorant.