Twin electric outboards

[Wlid blue yonder]

Hello newbee here.
I'm in the design stage of converting my classic caraboat to electric propellsion on a budget.
The question is I'm thinking of fitting 2 Bison 24v 100lb trust trolling motors rather than a 120lb single unit but where should I fit them? Normally with twin props they turn oppersite to each other (one anticlockwise and one clockwise) but with these electric motors they only turn one way. Will this course a problem?
Also I'm concidering to fit them either side of the door so about 4 ft apart. Again is this wise?
The caraboat has a cathedral hull.

Thank guys

 

[oldgit]

Some boats manage perfectly well with two props turning in the same direction.

 

[Tranona]

Just try it. Can't come to any harm, although keeping them running together at the same speed and in the same direction might be a it of a challenge.

 

[stelican]

If DC voltage would it be possible to reverse inputs as is done with an anchor winch.

 

[westernman]

The biggest problem is likely to be finding the "reverse" propeller. I.e. the one which gives forward thrust when the motor is running in reverse.

 

[Sea Change]

I've used various twin (petrol) outboard boats over the years, up to 2x350hp. Never had contra-rotating props. Never had any problems.

I do also have a Bison, word of warning, they don't like daily use in saltwater. You might want to swap out mild steel components for stainless, and regularly rinse in fresh water, apply grease and WD40 etc.

 

[Chiara’s slave]

I too have had twin outbosrd RIBs in various power ratings and only one was contra rotating. That was great, but the others were 100% functional

 

[QBhoy]

Would it be annoying of me to suggest that it may not be much of an issue or make it here nor there, overall…?
Just perhaps with it maybe being not being a highly thoroughbred hull..or the type of hull that bothers too much about the perfect set up. If she was, perhaps even the notion that she would likely only have a single outboard on her, might be more of a thought to ponder. That said…without having it in mind exactly what the hull shape or profile is actually like on her, if she might be likely to feature a hull profile, not lending itself any to the idea of and offset outboard, that’s maybe food for thought. (It’s in my head that they have a tri shape dory type hull with a kind of tunnel area between the hulls at the stern, where an outboard can pull and propel) Especially if propulsion and/or steering ability is compromised. I must have a look up on them. Interesting wee things.
Finally from me, I’m not certain that the idea of on the cheap, is usually a phrase associated often to electric outboards. Not those of any quality or useful function perhaps.
Anyway…love to follow your progress with this. Good on you for bringing back such a rarity to life. Best of luck.

 

[Wlid blue yonder]

Thank you QBhoy for taking the time to reply. As the caraboat will be used mainly on land and rearly see water (maybe 3 or 4 times a year) I don't want to go overboard on a spending spree. This caraboat would originally had a waterjet propellsion system with a onboard 4 stroke engine so even a outboard is a modification. Having a single motor would have less problems to solve (and overall cheaper) but twin motors would be more fun. I guess it's all down to water displacement.

 

[QBhoy]

Thank you QBhoy for taking the time to reply. As the caraboat will be used mainly on land and rearly see water (maybe 3 or 4 times a year) I don't want to go overboard on a spending spree. This caraboat would originally had a waterjet propellsion system with a onboard 4 stroke engine so even a outboard is a modification. Having a single motor would have less problems to solve (and overall cheaper) but twin motors would be more fun. I guess it's all down to water displacement.

Ah. Got you. Not sure I knew they were jet powered at all.
Fun is what it’s all about. You’re on the right track either which way, with that thinking.
Keep us up to date for sure !

 

[colhel]

I remember seeing a Caraboat as a kid and thought they were great. Can you keep us updated on your restoration?

 

[Wlid blue yonder]

If DC voltage would it be possible to reverse inputs as is done with an anchor winch.

Possible but I doubt if I can get a Propeller to suit.

 

[Wlid blue yonder]

I remember seeing a Caraboat as a kid and thought they were great. Can you keep us updated on your restoration?

Once I get some photos resized I plan to post some.

 

[wombat88]

If it originally had a waterjet propulsion system maybe a Warrenjet outboard would be more appropriate (and bonkers). I sold one recently that I had used once much to the amusement of onlookers. I think it went for £40.

 

[Wlid blue yonder]

Hello newbee here.
I'm in the design stage of converting my classic caraboat to electric propellsion on a budget.
The question is I'm thinking of fitting 2 Bison 24v 100lb trust trolling motors rather than a 120lb single unit but where should I fit them? Normally with twin props they turn oppersite to each other (one anticlockwise and one clockwise) but with these electric motors they only turn one way. Will this course a problem?
Also I'm concidering to fit them either side of the door so about 4 ft apart. Again is this wise?
The caraboat has a cathedral hull.

Thank guys

 

[colhel]

Brilliant! One day all boats will be made like that

 

[Wlid blue yonder]

If it originally had a waterjet propulsion system maybe a Warrenjet outboard would be more appropriate (and bonkers). I sold one recently that I had used once much to the amusement of onlookers. I think it went for £40.

Hello newbee here.
I'm in the design stage of converting my classic caraboat to electric propellsion on a budget.
The question is I'm thinking of fitting 2 Bison 24v 100lb trust trolling motors rather than a 120lb single unit but where should I fit them? Normally with twin props they turn oppersite to each other (one anticlockwise and one clockwise) but with these electric motors they only turn one way. Will this course a problem?
Also I'm concidering to fit them either side of the door so about 4 ft apart. Again is this wise?
The caraboat has a cathedral hull.

Thank guys

 

[Wlid blue yonder]

Hello newbee here.
I'm in the design stage of converting my classic caraboat to electric propellsion on a budget.
The question is I'm thinking of fitting 2 Bison 24v 100lb trust trolling motors rather than a 120lb single unit but where should I fit them? Normally with twin props they turn oppersite to each other (one anticlockwise and one clockwise) but with these electric motors they only turn one way. Will this course a problem?
Also I'm concidering to fit them either side of the door so about 4 ft apart. Again is this wise?
The caraboat has a cathedral hull.

Thank guys

A question on hull displacement.

I attach a photo of the hull. I'm assuming a single motor would be most effective due to the tunnel where the waterjet would have exited. Can anybody suggest the effect the hull would have on twin motors positioned near the 60mph stickers?
I guess I'm looking at torque rather than top speed possible as I'm aiming at around 3 to 4 mph max.
I'm still bouncing from single and twin motors

 

[Tranona]

I am not sure even 2 motors of that power will give you much speed or particularly control. It is not clear where the waterline is, but the location you propose is at least in clear water. You will need a substantial bracket for mounting each motor and connecting them so that you can use them for steering. I assume the water jet was directional controlled by the steering wheel. Controlling and steering the outboards from the original wheel will be quite a challenge.

 

[Wlid blue yonder]

They sit high in the water and the bottom set is exposed. The original jet water wasn't very effective and the story goes it was the downfall of the caraboat in production. Designed for canals system. I'm basing my design on a caracruiser that's slightly smaller and lighter as it doesn't have a built in trailer. I know of one of these running with a Bison 24v 100lb brushed motor so I'm fairly confident the Bison m250 would push it along in the right conditions.