V-Hull or Flat Bottom John boat WHICH is most stable?

comstox

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Some of you guys have been guiding me along with a winter project. I'm building a small 10' to 12' boat for cruising up and down the Connecticut River here in New Hampshire.
Which would be a more stable platform to start from? Background. This boat will probably have a 15HP but no bigger than a small 20hp engine.
So what will it be??? Flat or V-hull???

flat vs v-hull - Copy.JPG
 

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flyingscott

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The wider boat will be the most stable. Both of those boats are flat bottom, the only V on the boat on the right is the bow. The jon boat will give you more useable room but if it is narrower it will be less stable.
 

Skipper Sean

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The flat bottom boat will not be as stable on the river as a v hull as the v cuts the water better especially when it gets rough on the river. But with a v you have more draft. If you plan on fishing shallow creeks and so fourth the flat bottom has its advantages because of the lower draft. When I take my Jon boat out and the water is rough it beats the heck out of me. But to me that?s the price you pay to get where the fish are because you can raise the motor and troll on in to the honey hole and catch fish all day! Now a modified v will give you less of a draft than the deep v. It?s seems like you give up one thing or another with the different hull designs to pick one over the other is tough because different people are looking for different things. Are you mainly going to fish with it in the shallows or will you be deeper river fishing? When at anchor the Jon Boat is more stable for moving around the boat for fishing. I believe most of the newer bass boats have a modified v hull and not a deep V so it has a lower draft to get into shallower spots and for handling while moving. Because it seems like my 12 foot Jon Boat sometimes has the turning radius of the Queen Mary.
 

comstox

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The boat will mostly be a runabout type cruising boat, NOT for fishing. The CT River is mostly deep enough for any boat that drafts 2.5 ft or less. Any more draft and you would have to be VERY careful.
I'm leaning towards the V. V is for Victory!!!
I should note this too: We are usually on plane and just plain ole' cruising down the river. We'll sometimes go about 25 miles one way down to Hanover, NH (to the Dartmouth College Campus, ) get out and go eat lunch or get a coffee and cruise all the way back to the launch ramp. As a matter of fact I'll post a FaceBook "memories" video of us doing just that! Link to come shortly!
 
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comstox

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Also, HOW FAST do you think a properly dialed-in 9.9 will take the V-Hull???
 

Scott Danforth

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Also, HOW FAST do you think a properly dialed-in 9.9 will take the V-Hull???

you may not even get the boat on plane with a 9.9 so my guess 4 knots max. if you do get it on plane 12 knots
 

BTL

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I've owned both and I'd go with the v-hull every time. Flat bottoms are not fun in any sort of chop. With a 9.9 and passengers I don't think you'll get on plane at all though.
 

garbageguy

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+1 on the above - suggest the V and bigger than a 9.9, if you can

I would like to see your boating pics, they're ALL good (especially when not boating myself) - but not Fbook'er - can you post them here?
 

JimS123

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A semi-v hull (right photo) would be optimum for your application and would be the more stable of the 2. A Jon boat (left pic) is a poor choice for normal cruising.

A 12'er with a 9.9? I can't believe the answers you got for HP requirements. Our little 13.5' tinny is a 14R (rugged duty) and has more freeboard than the average utility boat. It runs awesome with a 9.9.

She planes just fine with a 9.5 'Rude with 2 adults and 2 pre-teens. My 9.5 gave the same performance as my 9.9. One time I had a 25 on her (max HP) and she was a little squirrely. Settled on an 18 as optimum for max speed potential. In the end the 9.5 went back on and remains to this day.

IMHO, a Jon is only good as a rowboat, or with minimal HP, when you are fishing up the creek with minimal waves.

My guess is that a 12' V-hull (semi V that is - like the pic - approx weight 175 lbs) with a 15 HP 2-stroke and 2 adults (350 lbs) would get you about 10-15 statute mph.
 
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Sea Rider

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If going for a under powered OB say a 9.9 HP, you can always maximize a less pitch prop to pull wot revs towards max wot rpm range, will give better hole shot along carrying more load and more fun planing up river current than with factory delivered prop.

For that adventure will need to install an induction tach to check achieved max wot rpm as loaded, once knowing if in need to pull wot revs bit higher can go for a less pitch prop. Don't change prop blindy, can over rev the OB and not know all about it.

Happy Boating
 

comstox

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I have decided! Check this out boyz! I am going to go take a look at this on Thursday or Friday. Comes with a 15HP Merc Force 2 cycle tiller motor. How fast do you guys think this will plane with (2) 150lb people?

12 v hull fiberglass.jpg

15 Merc.jpg
 

Sea Rider

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Difficult to tell, probably a 15 HP is a under powered OB for that lenght boat. What suggested on post 12 applies if wanting to get full15 HP out of that OB. My 3 under powered OB's have maximized less pitch props and the performance difference is oustanding compared to factory delivered props.

Happy Boating
 

JimS123

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That's a little light boat with not much freeboard. A 15 is not under powered, but that's just my opinion.
 

hardwater fisherman

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I agree that a 15hp is not under powered for that boat. That boat was made close to where I live. And I have seen several of them out on the water. I think it is rated for a 20hp max. Or at the very most 25hp. The ones I have seen rated for 25hp are deeper. Most of the people around where I live run a 9.9hp on a boat like that.
 

Sea Rider

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Not an issue running a 9.9 or even a 8 HP-OB, i'll bet you that none runs safely those 9.9 HP with a maximized prop for their given load, maximizing a prop is a night/day boating difference. Anything under max rated OB stated on tech plate for a given size boat is considered under powered. Doesn't mean OB will go dead. A prop max cures it all specially if like running wot as max loaded.

Happy Boating
 

comstox

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... I have seen several of them out on the water. I think it is rated for a 20hp max. Or at the very most 25hp.
It has no occupancy/limit tags to reference. The guy I'm buying it from said the same, He thinks 20 or 25 would be perfect!
Thanks for the input!
 

JimS123

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Not an issue running a 9.9 or even a 8 HP-OB, i'll bet you that none runs safely those 9.9 HP with a maximized prop for their given load, maximizing a prop is a night/day boating difference. Anything under max rated OB stated on tech plate for a given size boat is considered under powered. Doesn't mean OB will go dead. A prop max cures it all specially if like running wot as max loaded.

Happy Boating
That should be a sticky. Almost nobody understands that. Including some of the manufacturer's. Just throw HP at it and damn the gasoline.....LOL.
 
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