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Electric boats

Posted: Sat, 03 Nov 2018, 23:42
by Geoffozz
G'day everyone
I have basically promised the wife that she can have a boat. But we agreed that we weren't keen on an outboard. So we came up with the idea that we might have fun planning and building an electric boat.

It makes sense (well, for now, anyway) as in most cases the range requirements are quite low. There are not many issues with power steering, brake boosters and the like as in an automobile conversion. As far as I am aware, there are also less issues with NCOP requirements, so there may be more flexibility in design.

Broad specs so far:
Roughly 5 to 6 m overall length
Probably a tri-hull design as we have had one of those and it was very stable with lots of interior room.
Planing hull, not displacement.
Performance roughly equivalent to a 60hp outboard.
Has to be able to putter along when necessary if we are "shadowing" a sailboat with young people on board (we have a Sea Scout involvement).
No interest in towing skiers or donuts.
Enclosed prop or jet propulsion.

This is very early days and I have lots to learn, but I thought I'd put this out there as a conversation starter. Given those basic parameters above, where should I be looking for motor and controller specs, please?

Re: Electric boats

Posted: Sun, 04 Nov 2018, 09:09
by lobster
Hi Geoff,

Have a look at this Link.

http://www.evalbum.com/type/BOAT

You may find someone with the same criteria has already built one.

Cheers

Re: Electric boats

Posted: Mon, 05 Nov 2018, 12:43
by Richo
I was looking up the electric solar catamarans a couple of weeks back.
I came to the conclusion that boats consume 10x what a car does.
So ~1,500Wh/km - sorry I'm not a boatie you'll have to convert it back to boat terms.

Rotto and back would need like 90kWh of pack.
Even a leisurely cruise around the coast would need a ludicrously big battery pack.

Re: Electric boats

Posted: Mon, 05 Nov 2018, 12:52
by Johny
Richo wrote:
Mon, 05 Nov 2018, 12:43
I was looking up the electric solar catamarans a couple of weeks back.
I came to the conclusion that boats consume 10x what a car does.
So ~1,500Wh/km - sorry I'm not a boatie you'll have to convert it back to boat terms.
Yes it makes more sense to have electric as the mooring/anchoring/Marina power on a sailboat rather than a petrol outboard. I'm thinking trailer sailers here. The downside is carrying around 100kg of battery for the occasional use - but there are some who do this.

Re: Electric boats

Posted: Mon, 05 Nov 2018, 18:01
by Adverse Effects
have a look through for something to base you boat on

https://www.google.com/search?q=electri ... 40&bih=753

Re: Electric boats

Posted: Tue, 06 Nov 2018, 12:39
by Richo
These are the ones I was looking at:
http://soelyachts.com/soelcat-12/

Re: Electric boats

Posted: Tue, 06 Nov 2018, 12:52
by Richo
My thought that there must be a size where the sun+battery can keep it going non-stop at a respectable pace.
Well at least until the batteries wear 8+ years.
But I'm thinking big.

https://yatta.club/uncategorized/hydrop ... catamaran/

Re: Electric boats

Posted: Tue, 06 Nov 2018, 12:58
by Richo
Geoffozz wrote:
Sat, 03 Nov 2018, 23:42
Performance roughly equivalent to a 60hp outboard.
Presumably this would mean 45kW continuous.
As a 3-phase induction motor this is 15kW 4-pole, 110kg.

Any smaller suggestions?