Question regarding max size of motor for my boat and opinions.

northwoodslivin

Petty Officer 1st Class
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Feb 3, 2010
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Hello guys and gals! :)

I have a question. I just picked up a 14' Peterborough Super 400 aluminum fishing boat. I need to get a motor for her, and on the plate it says max 10kw. My question to you folks is, after a bit of research it is my understanding through calculation that 10kw=13.4HP NOW...If that is true, with that said I am eyeballing a couple 15hp Johnsons, one is an 87 other is an 89, both short shaft "my transom is 15" so I take it that these motors are the right length?" I see that if I we're to put one of these 15's on my boat it would be overpowered slightly? Is this going to be a bad thing?

Also, there is a person at my brothers work who is selling a 20HP short shaft, I do not know the make model or year yet as I havent went to look at it, but the price is cheap "must be an oldie" IF I go and look at this motor and it checks out well for the price, is 20HP a big no no for my boat? "this motor is half the price of the other two I had mentioned"

I intend to mainly use my boat for fishing small lakes, mainly to get to places and do trolling. I have read that the 15HP Johnsons are essentially a 9.9 with a bigger throated carb? I also read that these 15's are not as good for low speed trolling? Any first hand experience fellas? I will be mainly fishing for small mouth bass and walleye.

Thanks so much for everyones input in advance!
 

tashasdaddy

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Re: Question regarding max size of motor for my boat and opinions.

technically the 15 is over powering the boat, in legal terms, would be considered an unsafe boat in a legal problem. 20 would be way over kill. if trolling for bass etc, buy electric for trolling.
 

smokeonthewater

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Re: Question regarding max size of motor for my boat and opinions.

agreed.... 20 is too much.... I would work through the formula for hp rating and see what that tells you.... I would also put a new capacity plate on with the rating in hp instead of kw... It may well be that 15 works out ok... also a check with the manufacturer may get you some good info
 

northwoodslivin

Petty Officer 1st Class
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Re: Question regarding max size of motor for my boat and opinions.

Hmm.

So a 15 would be ok I take it then? only 1.5hp over. But a 20 is definately a no go? Reason I ask is because I can get the 20HP for 200 dollars and the 87 johnson for 400 and the 89 johnson for 500 "Canadian funds"

And I do plan on getting an electric motor this summer to add as well.
 

northwoodslivin

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Re: Question regarding max size of motor for my boat and opinions.

agreed.... 20 is too much.... I would work through the formula for hp rating and see what that tells you.... I would also put a new capacity plate on with the rating in hp instead of kw... It may well be that 15 works out ok... also a check with the manufacturer may get you some good info

Thanks for that,

Well, I do know that my boat is made in Canada, Peterborough to be exact but I am not sure if they still make boats. I can't find anything on my model of boat anywhere in the internet "14' Peterborough Super 400"

I do know that the plate was put on there by the people who you need to register the boat with, so maybe it could be wrong? Heck, I see people on youtube with 15's on 12 footers as big as 40hp on 12 footers "I know that is just dumb"

How are these 15's on gas? from all I read they are very solid motors. I had a 65 Johnson Seahorse 3hp twin that was bullet proof. Really like the Johnsons.

If anyone finds anything on my model of boat, I would greatly appreciate it!
:)
 

smokeonthewater

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Re: Question regarding max size of motor for my boat and opinions.

nobody said a 15 was ok as rated... if your figures are correct then it is expressly not ok.... You could choose to do it anyway and likely no harm would come of it but it is a chance you take If you are able to find new info you could prove that it was indeed safe

edit you posted while I was typing..... do a search on figuring uscg capacity
 

northwoodslivin

Petty Officer 1st Class
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Messages
323
Re: Question regarding max size of motor for my boat and opinions.

nobody said a 15 was ok as rated... if your figures are correct then it is expressly not ok.... You could choose to do it anyway and likely no harm would come of it but it is a chance you take If you are able to find new info you could prove that it was indeed safe

edit you posted while I was typing..... do a search on figuring uscg capacity

Smokeonthewater,

Could you please enlighten me what is not ok? I apologize, I am not really smart in this area. What might be a problem using a 15HP? techincally speaking, according to the plate that was put on the boat it says 10kw, so that is 13.4HP. Does an extra 1.6HP pose a danger? if so could you please tell me what might happen?

I am only using this boat on the small lake on my property which is totally not a busy boating lake! Please enlighten me if you could.

:)
 

smokeonthewater

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Re: Question regarding max size of motor for my boat and opinions.

well if you are on private property then you don't need to worry about tickets ..... it's a legal concern more than a safety issue..... Again tho it is less important on private property although not totally unimportant.... kinda like telling the cop it was only 10 over the limit.... it's taking a chance
 

northwoodslivin

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Re: Question regarding max size of motor for my boat and opinions.

Interesting.

I think the law may be different in Canada. I cant say I have ever heard of this before. I will definately be looking into it as I am a guy that plays by the rules :) I was concerned about the boat with this motor more so.
Thanks bud
 

Silvertip

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Re: Question regarding max size of motor for my boat and opinions.

What is not being explained very well is the "legal issue". The boat is not going to be unsafe with less than two HP over its rating. The legal issue arises should you have an incident of any kind where someone is hurt, regardless how seriously. In this country we are overrun with attorneys (more commonly called ambulance chasers) that will find a way to sue you. All it takes is an engine over the stated maximum HP rating. If the personal liability laws are different in Canada, then properly operated, you would probably not have an issue. We are simply trying to warn you of potential "legal" issues regarding overpowering. The 15 will troll just fine. I used to troll with a 40 Evinrude.
 

tashasdaddy

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Re: Question regarding max size of motor for my boat and opinions.

technically, the 15 is over powering the boat, in legal terms, would be considered an unsafe boat in a legal problem. game warden and red tag your boat, make you go home. if an accident, insurance may not cover you, attorney's will have you in a homeless shelter. LEGAL PROBLEM.
 

H20Rat

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Re: Question regarding max size of motor for my boat and opinions.

can anyone site a SINGLE case of an overpowered boat being used in a LEGAL prosecution?

Along the same lines, many states don't have any safety certification or requirements, I have checked my state laws regarding overpowering, and no mention of engine size vs plate. I'll also personally been in boats that were stopped by a game warden for safety checks, and the warden made absolutely no mention of the 150 on the back of a 15.5 ft boat that was rated for 90. (almost every warden I've met is far more interested in common sense safety issues than nit picking every little item.)

I worked in insurance for quite a few years, and insurance rates and insurability itself depended on engine size, but we never once questioned or denied a claim because of it. In fact, insurance didn't even know or care what was on the capacity plate.
 

ezmobee

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Re: Question regarding max size of motor for my boat and opinions.

From a more practical perspective.....9.9's and 15's from most manufacturers typically use the same or similar block. But a 20 jumps up to a larger one. I think the weight difference could be significant. A 9.9 or 15 would be ideal.
 

trendsetter240

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Re: Question regarding max size of motor for my boat and opinions.

I've been through this same question myself several times and have done a lot of research.

In Canada there is no legal requirement to keep your outboard motor under the maximum stated on the capacity plate. The issue is one of personal safety and potential liability in the case of an accident. i.e. Someone may try to sue you and use the fact that your boat is "overpowered" as an indication that you were being reckless.

"Boats not over 6.0 m long, and powered by an outboard engine of 7.5 kW (10 hp) or more, must also have a Capacity Plate permanently attached in plain view. The capacity plate states the recommended safe limits of engine power, which is the recommended gross load capacity that can be safely carried in the hull. Gross load capacity is defined as; the total weight of equipment, stores, fuel, motor assembly, steering controls, and equivalent number of adult persons. Remember that these are maximums for fair weather operation."

Quote source : http://www.boaterlicences.com/online_course_safety.php
 
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