6hp Tohatsu - 3.5 tonne Centaur - speed through flat water

dylanwinter

dylanwinter

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www.keepturningleft.co.uk
yesterday when the engine control grub screw loosened itself I was forced to put the Tohatsu on the back of the Centaur to get me home

would anyone here like to guess what speed half revs gave us through flat water?

I ran it in two different directions just toget an accurate through the water figure

I am digitising the film now and will post the answer to my question in the morning.

Dylan
 
Based on absolutely nothing at all, but guessing that displacement weight will make little difference when up to speed... 4.5 Knots?
 
I don't think you would have to cane the engine......

and I do think it would work ok.....and my guess would be above 4kts as well. I can't imagine it would do 5 but am fully braced to be wrong.
 
dylanwinter said:
yesterday when the engine control grub screw loosened itself I was forced to put the Tohatsu on the back of the Centaur to get me home

would anyone here like to guess what speed half revs gave us through flat water?

I ran it in two different directions just toget an accurate through the water figure

I am digitising the film now and will post the answer to my question in the morning.

Dylan
Click to expand...

I used to sail a first 24, which is like a flimsy dinghy compared to a centaur. It had a 9.8 outboard in a well which was better than being slung on the back.

It did 4+ knots with the engine screaming and using fuel at an alarming rate.

Based on that, 2.7 is my guess.
 
Elessar said:
I used to sail a first 24, which is like a flimsy dinghy compared to a centaur. It had a 9.8 outboard in a well which was better than being slung on the back.

It did 4+ knots with the engine screaming and using fuel at an alarming rate.
Click to expand...

Something must have been badly wrong because with my 9.8hp on the back of a 10m trimeringue I get 6.5 knots maximum in calm conditions. If I reduce speed to 5.5 knots I get 22 naughtickle miles to the gallon. 10hp on a First 24 should have pushed it around no bother at all. I used to have 7.5 hp on a Extravert 22 and the problem there was going slowly enough. Tickover in gear was too fast for berthing.
 
I had to fit a 2hp Honda outboard to my Kingfisher 20 to get us up the Exeter canal in November, & was wondering when I did that whether it would work. To my surprise we went very well. I didn't measure the speed but it was quick. My guess is that it will be hull speed - what is that, 6 or 7 knots or so?
 
Elessar said:
I used to sail a first 24, which is like a flimsy dinghy compared to a centaur. It had a 9.8 outboard in a well which was better than being slung on the back.

It did 4+ knots with the engine screaming and using fuel at an alarming rate.

Based on that, 2.7 is my guess.
Click to expand...

Could you have had the wrong sort or prop? I have 8hp on the transom of our First 235 and get 6.5 knots no bother.
 
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