# Is 70hp too much power on 14ft flats boat?



## WhiteDog70810 (May 6, 2008)

Use the hull number to identify the builder and call them up if still in business. If the builder is no longer in business, see what a similar hull is rated to. My gut says the hull will squat like a dog taking a dump at rest and be in recklessly over-powered when under way.

Nate


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## Tonyskiff (Jan 7, 2018)

WhiteDog70810 said:


> Use the hull number to identify the builder and call them up if still in business. If the builder is no longer in business, see what a similar hull is rated to. My gut says the hull will squat like a dog taking a dump at rest and be in recklessly over-powered when under way.
> 
> Nate


There is no hull number or any numbers at all. No brand name either. I’ve seen other ski boats similar to this one with with 85hp. I’m not sure what to do.


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## Smackdaddy53 (Dec 31, 2012)

Hang one on her and see! It can’t be any higher horsepower to weight ratio than a 21 foot flats boat with a 250 or a 23’ with a 300. It will probably squat pretty bad at rest but hit the throttle and it should get up and go.


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## Tonyskiff (Jan 7, 2018)

Smackdaddy53 said:


> Hang one on her and see! It can’t be any higher horsepower to weight ratio than a 21 foot flats boat with a 250 or a 23’ with a 300. It will probably squat pretty bad at rest but hit the throttle and it should get up and go.


Thanks!


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## Capnredfish (Feb 1, 2012)

Go with it. Majority of 40-50hp are near that weight. What else would you go with, a 25?


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## lemaymiami (Feb 9, 2007)

If you really want it to be a "flats skiff" - then it has to float as close to level as possible - with nothing in it other than motor, battery(s), and fuel tank... Every degree downward at the stern means that hull will need more water under it....

If it was just a "go fast" or a ski boat - you'd want every bit of power you could put on the transom but that's just not the case with a boat intended to float shallow (that you can actually walk around without getting your feet wet as you near the stern..).

Of course, you can rig it any way you choose -you're the one that will be using it. By the way - some boat insurance outfits will insure anything - as long as you're willing to pay...


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## Vertigo (Jun 3, 2012)

You won't need a lot of power to get a respectable cruise speed with that hull. The difference between 70 hp and 25 hp will be more than 100#, and on a small boat with a shallow V hull, that will compute to a significant increase in draft. More power means more weight, more draft, less fuel economy, more risky handling and more insurance. I'd stick a nice reliable 25 hp two stroke on the transom and be happy.


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## Capnredfish (Feb 1, 2012)

Might want to weigh it before buying power. You added a lot of glass and resin.


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## Mike C (Feb 27, 2017)

Put the hull in the water without a motor on it and mark the front and rear water lines with a grease pencil. 
Place weight equal to the engine weight like sand bags on the transom as far back as you can get them. Mark your hull again. 
You might also want to do the same with something like 125-150 pounds to get an idea of how it will sit with a mid powered motor. 
Batteries, fuel and other gear will change the center of gravity also. 
I would float it with all of my gear and decide from there which motor to use.


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## Tonyskiff (Jan 7, 2018)

Mike C said:


> Put the hull in the water without a motor on it and mark the front and rear water lines with a grease pencil.
> Place weight equal to the engine weight like sand bags on the transom as far back as you can get them. Mark your hull again.
> You might also want to do the same with something like 125-150 pounds to get an idea of how it will sit with a mid powered motor.
> Batteries, fuel and other gear will change the center of gravity also.
> I would float it with all of my gear and decide from there which motor to use.


Got it. I’m leaning towards this idea. I’m gonna use 50gallon bucket on the back to see if boat can handle 70hp or 257lb. What do you think how far down is acceptable? For the speed wise will this hull be ok? Thanks!


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## Capnredfish (Feb 1, 2012)

Is there not a degree measurement a boat should typically sit. Thought I read 3 or 5 degrees some time ago. 
Still a fan of the horse power and throw one of those animal proof coolers with 14 days of ice instead of 7 and things should level out nice. Maybe adding 1/2 inch draft. 
I like the idea from Mike C. But it still takes a certain amount of power to move boat, gear and people. It needs to be able to get on plane, get out of harms way, cruise at not wide open throttle. 
If it can't then it's a row boat.


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## topnative2 (Feb 22, 2009)

USCG has the formulas for HP to size. Fl has max HP rules for boats under20'(?).


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## Smackdaddy53 (Dec 31, 2012)

I grew up fishing on a 1236 flat bottom aluminum river boat with a 25 Johnson. Still have it.


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## yobata (Jul 14, 2015)

Tonyskiff said:


> There is no hull number or any numbers at all. No brand name either. I’ve seen other ski boats similar to this one with with 85hp. I’m not sure what to do.


is there a hull number on the title? Or registration?


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## Mike C (Feb 27, 2017)

The title should give you a good starting point for the manufacturer and actual hull specs


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## Tonyskiff (Jan 7, 2018)

Hey fellows. This boat I picked up from a local junk yard $100. When I got it there was no title or any hull numbers on it. Guy said no one knew what it was. I went to Dmv and got a new title as home build since boat is less then 16ft I don’t have to do sertification with FWC. I got this formula somewhere on the net, it goes like this: transom width (widest point) x total length of a hull x 2 minus 90 = HP. All calculation must be done in linear ft. Mine come out @ 39hp. Yeah also you have to round up to the closest 5 up. 

In my case I lowered the weight of the boat by removing all wood flooring and stringers, old top cap and use composite construction. It much lighter then what it was before. The difference between 20” shaft Yamaha f40 and f70 is only 29lb. My concern is the stability of the boat when I like speed.


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## Capnredfish (Feb 1, 2012)

You will never know if you put a 25 on it.


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## Vertigo (Jun 3, 2012)

It's a light 13.8 ft boat that the owner wants to convert to flats fishing. Flats fishing means that running and floating shallow are more important than top speed. Sticking max hp on the transom is just going to defeat the purpose of the conversion (unless secretly the owner really does care more about going fast than fishing). Safe top speed in chop with a tiller steered sub 14' boat is going to be way less than can be attained with 25 hp. Why add more weight and power that can't be safely used?


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## fjmaverick (Sep 18, 2015)

People put 90hp on 15' hobie skiffs
With the right hull it can be done


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## Vertigo (Jun 3, 2012)

fjmaverick said:


> People put 90hp on 15' hobie skiffs
> With the right hull it can be done


People do all sorts of strange, dangerous and down right stupid things with boats. Just because it can be done doesn't mean it's a good idea.


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## Smackdaddy53 (Dec 31, 2012)

Vertigo said:


> People do all sorts of strange, dangerous and down right stupid things with boats. Just because it can be done doesn't mean it's a good idea.


Remember when someone on here told us tunnel hulls are dangerous because they flip over all the time?


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## Smackdaddy53 (Dec 31, 2012)

fjmaverick said:


> People put 90hp on 15' hobie skiffs
> With the right hull it can be done


No different than a 300 on a 21’ flats boat.


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## Capnredfish (Feb 1, 2012)

I still doubt 70 is too much. Prop it for get up and go instead of top speed then.


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## barrell (May 17, 2016)

No one can answer your question but if it has scuppers I would not want water pouring in the back of boat. Test it with 5 gallon buckets of water. And the wheight of two or three batteries if you are planning on a trolling motor.


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## jimsmicro (Oct 29, 2013)

Man it's got an almost 70 inch beam, that's a lot of hull in the water to push. I think the 70 is going to be great. The F70 is the lightest four stroke 70 made as far as I know. Since you're already glassin' you could put some float pods on the back like an old Hewes or something. Might help with squat.


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## Will Morrow (Dec 25, 2017)

are you ready to pass jet skis and squat, I think it will be fun


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## No Bait / Lures Only (Apr 10, 2011)

I had a hull, kennedy kraft 13'6' hull modified v hull 1969 and had a 35 mercury and then a 50 mercury for power and never had any issues with the boat. Used to ski with it as well, also single slalom and 2 double skis. I think the boat was rated for 25 hp....


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## Tonyskiff (Jan 7, 2018)

After all the thinking Ive decided of going with Suzuki df60a it only weights 229lb.(same as Yamaha 40hp) 947cc displacement. Better gear ration. Should be good power for 14ft boat. If you have experience with suzuki please share. Thanks.


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