C17

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jacko345
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C17

Post by jacko345 »

What would be the maximum recommended HP for a C17 I have an older model Johnson 135hp is this likely to be to heavy

OrangeQuest

Re: C17

Post by OrangeQuest »

In the study plans it only says 50hp with no max hp but I would guess a 135hp would be a little to big. The C19 design says it could use a max of 150hp and the is a cabin version.

Fuzz
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Re: C17

Post by Fuzz »

Is the motor an older model 2-stroke? If so I bet the weight will not be too much. Seeing as you already have the motor I think I would give it a try. You very well could have way too much motor and be able to push the boat to speeds it was not intended for. If this is the case it would be very important that the skipper used their brain and refrained from shoving the throttle all the way to the stop :help:

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topwater
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Re: C17

Post by topwater »

I can't think of one person who has extra HP and not used it , at least once :wink:
Novi 23 finally launched !

Rmarsh
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Re: C17

Post by Rmarsh »

jacko345 wrote: Wed Mar 21, 2018 6:08 am What would be the maximum recommended HP for a C17 I have an older model Johnson 135hp is this likely to be to heavy
I have a 60 hp Yamaha on my C17, weighs about 240 lbs. The Johnson 135 is probably 350 lbs. Too heavy and too much power for this hull imo.
Not saying you couldn't use it...just not a good fit.

TomW1
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Re: C17

Post by TomW1 »

I did some research and an older model 135HP Johnson weighs 271lbs. So weight is not that much of a problem as a Yamaha 50 or 60 is about 245lbs. The problem is the HP. The bottom of the boat is not designed to handle that much HP. It will oil can and basically destroy itself. While I am not sure of this I believe you would need 3/8 plywood and double layer of fiberglass for the bottom, I have not done a detailed calculation. Sell the Johnson and get a 50 or 60 so that it meets the requirements for this boat.

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

jacko345
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Re: C17

Post by jacko345 »

Thanks to everyone for the help. Best to source an alternative engine I think.

stevehewins
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Re: C17

Post by stevehewins »

I know this post is for a possible 135hp outboard to be put on a C17. But what's the smallest you can get away with? Anybody have a top speed they have reached with the recommended 50hp?

TomW1
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Re: C17

Post by TomW1 »

A builder in England put an Evinrude 50 on his C17 and had top speeds in the low 30's. Tim may see this and respond, he and his boat are now in South Africa. Do a search in the Builders section down below, C17(Classic 17) in London to view his build. You might get a kick out of how he got his boat from behind his house to the street.

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

stevehewins
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Re: C17

Post by stevehewins »

Thanks Tom. Really appreciate the response and have looked up that build. Very impressive. Would a 75hp engine be ok? I know it's 50% more than recommended, just one has come up at what may be an affordable price.

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