Electric sailboat motor: new conversion project (update: project shelved)

[dcb]

lol, looks like you are real close can I suggest gluing the coupler back together and thread wrap it?

[MetroMPG]

Good idea. I had been considering a clamp/screw combo. Think it matters what kind of thread?

I've already epoxied it back together.

Version 1.1: I roughed up the inside of the shaft bore, applied a liberal amount of 2-part epoxy and put the shaft back in. The thought being: "make your own internal splines!" (C).

It lasted a little longer, but the epoxy sheared inside the coupler and it spun merrily around the input shaft.

It worked almost long enough for me to be sure whether a 1:1 motor:input shaft ratio at 24v will be enough for what I want. But not quite!

So I can adapt the coupler one more time and test again.

Also: if I'm willing to ditch the motor's commutator-end fan, I can turn the motor upside down and use the the external shaft instead of monkeying around with that little pump shaft and its weird interface to the motor.

[TroyRank]

Great Project! I am considering doing the same with a small (22-23') sailboat and a couple of trolling motors. A couple of 50lb thrust trollers should be more than sufficient to move a little 2300lb boat. Lead acid batteries are dirt cheap at around $50/kwh! It's too bad I cant add them to the keel as ballast I have a small electric generator, just in case I get in trouble and run out of juice.

Ill be watching you're project closely!

[nol2112]

This is a great project. I am very interested in your results. I too have an OMC saildrive that's caused me great frustrations over the years; and have been looking into an electric option using the existing saildrive leg. Question: does the water pump need to be blocked and removed? Could the existing setup be left in and re-routed or utilized to provide cooling for the motor & controller?

[dcb]

Originally Posted by MetroMPG

...Think it matters what kind of thread?...

I think it would look cool wrapped in sinew

[MetroMPG]

Sorry for the lack of updates/progress here. Project is still on the to-do list, but I've been getting my sailing fix on other boats and using this one as my floating cottage. (Pied-a-l'eau?)

Originally Posted by nol2112

Question: does the water pump need to be blocked and removed?

I removed the impeller from the input shaft, yes. Blocked the water intake externally, on the bottom of the lower unit outside the boat.

Could the existing setup be left in and re-routed or utilized to provide cooling for the motor & controller?

I suppose it could, yes. The challenge will be sealing the shaft, since in this boat at least, it's below the waterline.

I'll be back at this project in August, I figure.

[MetroMPG]

Originally Posted by dcb

I think it would look cool wrapped in sinew

Cat gut, yes!

[Jyden]

With the underwater drive / propellar permantly out, you should install it so that you have two options. "free wheeling" or "Power generating mode".

The propellar will spin as you sail. If theres a free gear it will spinn without much resistance, but if the electric PM motor is fitted you could use that as a generator to charge your batt3ries.

Resistance while generating power would be higher, but I will proabably only reduce boatspeed with something like 1 knot.

And you would be making your own current for the batteries and the boat.

Thoughts on that ?

[bestclimb]

Originally Posted by Jyden

With the underwater drive / propellar permantly out, you should install it so that you have two options. "free wheeling" or "Power generating mode".

The propellar will spin as you sail. If theres a free gear it will spinn without much resistance, but if the electric PM motor is fitted you could use that as a generator to charge your batt3ries.

Resistance while generating power would be higher, but I will proabably only reduce boatspeed with something like 1 knot.

And you would be making your own current for the batteries and the boat.

Thoughts on that ?

Likely less than a knot. The limiting factor for boat speed is hull length at the water line. A little extra drag in the water will not substantial slow the boat, as once the hull comes up to it's theoretical limit the drag from trying to drive up onto the bow wake goes up exponentially.

For cruising boats there are commercial tow behind and drop down generators to keep the batteries topped, would be neat to see one piece of equipment pull double duty.

I looked at a lot of systems when I had my boat for dc generation without running an inboard diesel, that I mostly wanted to pull out and replace with a small electric motor for docking when conditions made docking under sail "challenging". I had well built a 32 foot ferro-cement full keel double ender. it was cutter rigged.

[MetroMPG]

Very late update / wrap-up to this thread:

I ended up with too many land-based projects, so the boat was not used much in the previous 2 seasons -- it stayed on the hard last year in fact.

So, the conversion never got beyond testing the e-motor on the quick-n-dirty wooden lower unit mount.

This year, I sold a half-share in the boat to a couple I know, and they understandably wanted the gasser back in, rather than fussing with an experimental electric conversion.

So we tore down the motor this spring and replaced all the seals & gaskets. It went back in the boat before this year's launch and is working fine. The stinky, smoky, noisy (relatively powerful, long-range) 2-stroke lives again.