55lb Thrust Electric motor + small GRP Boat

jmw

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Hi All

I'm hoping that I might get a little advice......

My parents (in their mid 70's) are buying a 14 ft cuddy boat for river usage in rural France.

The river is damned at both ends (about 10km stretch) with almost no flow so more like a large canal.

It has been suggested that a MotorGuide R3 55lb thrust electric outboard should be sufficient to propel them and a couple of passengers at a sedate 2 to 4 knots.

I can't find any useful comparison between thrust and HP so has anyone got a view on whether this will be sufficient for their needs?

Thanks in advance.
 

BruceK

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I can dig out all the independent tests and there are some on youtube, but real world tests have squashed that idea on all but tenders and kyaks doing short hauls. So in a word No. You'd be better off with a small 3hp engine.
 

jmw

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Hi Bruce,

Many thanks for the info.

Petrol power is frowned upon in the river and the you tube test seems to indicate that it will do the job - just more slowly. This is not a problem as the ideal is literally 2 to 4 knots.

Admittedly, it's a bit slow for my liking but that's what they want!

If my maths is correct, 24.8 seconds (using a 55lb thrust motor) over 50 metres is a little over 8 minutes for 1km or 0.62 mile. This broadly equated to 13 minutes to do a mile which is a aprox 4.5 knots.

I appreciate that this would kill the battery quite quickly but 2 to 3 knots is reasonable if you are happy with the slow pace of life :sleeping:

Does anyone agree/disagree with my logic?
 

BruceK

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If petrol is a no go then its electric or oars. If its electric go for the minimum Wattage motor neccessary to propel the boat to the desired speed and a bit for wind to spare the battery. .... and fit oar locks. ..
 

wonky

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I've got a Flover 55lb motor and although I love it there is no way I would be happy with it on more than a small inflatable. How about a Torqueedo? Lots more power and I'm sure it would be adequate. (More expensive too!)
 

Tranona

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Torqeedo is the way to go for an electric outboard. Expensive but in a different league from those trolling motors with their lack of power and heavy consumption. Range though will always be a problem because of low battery capacity. The only real solution is a proper inboard electric power plant with large batteries. Commonly used in similar situations on hire boats that get maybe 5 or 6 hours running from a charge.
 

stigger

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I have a 55lb minn kota for my open canoe. With 2 adults and 2 kids on board it will happily cruise for 2+ hours at full whack on a 110ah leisure battery. Reckon we'd get 5-6 hours if just pottering. Reckon it gets to about 4 knots into the river current, 6 knots with it.

We used it recently to bail us out when the outboard impeller packed up on our 14ft speed boat. 2 adults, 2 kids and a 55hp outboard were propelled at about 0.5 knots against the tide and wind in Brancaster harbour... But we got there. With tide and wind we probably achieved 2 knots.

Hope that helps.
 

stigger

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P.S. I just noted you have a cuddy... Into the wind (and tide) if we'd had a cuddy we'd have gone backwards for sure... With the wind and tide we might have got to 4 knots ;-)
 
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