15 horsepower outboard on a 10' jon boat?

I had a 10' Jon boat. Basically all it was used for by me was to row out to where my 19’ speed boat was moored & swinging on its line about 70’ from the shore. I was 250 lbs at the time and the freeboard was just about non existence, no way would I put anything else in or on it.

My sons about 10 and 12 at the time would some times paddle around in the bay or fish from it. For the record they both could swim and they always used life vests and an adult was always on the beach. When I built a dock I get rid of the mooring and the *** Jon boat.

blackdeuce said:

If we buy a 6 hp motor with a 15 inch shaft, will it work with a 14 foot boat, or do we need a 20 inch shaft?

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The 15 inch shaft will work fine. That is what I have. The longer shaft motors are mainly for use as kickers on sail boats. The longer shaft will just get the prop down further and give you more opportunities to hit submerged objects. Believe me as I hit way too many of them running a 15 inch shaft. But of course I am running in shallow water.

I have a ten foot mini bass boat with a 7 1/2 hp motor on it and that's almost too big. Boat is rated for 7 hp so I could get a ticket for it too.
We put a 15 hp motor on my buddy's 14 foot flat bottom and it flew. Loaded down with duck decoys, dog and gear it was about right though.
Glad you're thinking of smaller motor or bigger boat though.

Let me expand a little on EQGuy's post; shaft length is determined by transom height. With the outboard mounted, the cavitation plate, (the doo-hickey above the prop), should be level with or below the bottom of the hull. I've never seen a jon boat with a tall transom unless it had been modified, so a short shaft would be fine.

-Klaus

Ok boaters, help me out on this, because I really don't know.

If I have 10 ft Jon boat, and the engine of a 7 hp weighs (for the sake of argument) 20 lbs. and I weight a hefty 350 lbs in my bare feet, wouldn't I sink *** first as soon as I stepped into the boat?

Or If a 15 hp motor weighed 40 lbs, and I only weighed 180 lbs, and I stepped into it, I'd be ok?

Next how fast I go, would that not depend on the pitch of the prop? High pitch = slower speed...Lower pitch = higher speed? Isn't that why there are some props with 2 blades, some with 3 blades and some with 4 blades, depending on what the load is going to be, given the same hp????

As far as the depth of the transom, I agree on the above comments.

Any boat, does it not matter on the balance of the load?

What little I know, if a V hull or a flat bottom, is loaded aft heavy, it will not plane????

All I know about boats and fishing is what I can see in the fish section at the super market.

WuzzFuzz

I had an 18 ft with a 175 for a bay boat------when you need to get out of Dodge--you need to get out of Dodge.
Blessings

WuzzFuzz-
Let me @ least cover your first supposition, i.e. your 350 lbs body in the stern, it could be done with a tiller extension, thus moving your bulk to the center of the boat where it would belong . The biggest issue would then be, how much freeboard, (the space between the water & the top of the gunwale), you would have. When you don't have a lot of freeboard, and typically jon boats don't have much when they're empty, things can get rather dangerous in any kind of seas. In the OP's case, given the weights of the two fishermen, a 10' jon boat is going to be scary enough on just about anything bigger than a stock pond without adding the weight of an outboard.

-Klaus

A good friend of mine tried to use a 10HP on a 12ft Jon. His "test run" was with no weight on the bow, and he went airborne within seconds of leaving shore. The motor was damaged when the prop left the water. Use only the recommended combinations!!

Ok, I think I understand some of it... From the bottom of the boat to the top of the sides is the "freeboard?. Right? So wouldn't it also make a difference of how much water is displace volume wise? I.E. A narrow Jon boat will not displace as much water as would a wide Jon boat, therefore would not a wide 10' Jon boat be more stable than a narrow one? The water would not reach and go over the top of a wide boat, compared to a narrow one???

To me, it would be like comparing a flat bottomed canoe with a row boat.

I don't know...maybe I'll invent a air mattress, with a place to put a motor..Then it won't sink.


WuzzFuzz

WuzzFuzz said:

Ok, I think I understand some of it... From the bottom of the boat to the top of the sides is the "freeboard?. Right? So wouldn't it also make a difference of how much water is displace volume wise? I.E. A narrow Jon boat will not displace as much water as would a wide Jon boat, therefore would not a wide 10' Jon boat be more stable than a narrow one? The water would not reach and go over the top of a wide boat, compared to a narrow one???

To me, it would be like comparing a flat bottomed canoe with a row boat.

I don't know...maybe I'll invent a air mattress, with a place to put a motor..Then it won't sink.


WuzzFuzz

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They make something like that already, called a Zodiac (a favorite of Special Forces)

I say YES, YES, YES!

Get a friend to video and you have the makings of a YouTube viral success.

Also might even get an episode on "When Vacations Attack" on the History Channel.

Lakesider, I know of the Zodiacs, but aren't they V shaped in the front? Where as the Jon boat is square in the front...Other than that, is there any difference between a Zodiac and a Jon boat? I know on the Zodiac, those side are full of air. Then is the floor of the Zodiac flat? Or does it have some air in it too?

As far as my mattress goes, it would be squared off as a mattress is squared. And the front could probably be made that it would be up in the front like a Jon boat....What I didn't include with my idea of the mattress type of boat, it would come with a free roll of Duck tape for repairs, if a person hit a hidden log, or if a person happened to do a bad cast, and the hook got embedded in the mattress somewhere.


WuzzFuzz

There is no way this is a sensible arrangement, 15hp on a 10" john. In most states here in the east it is downright illegal. I can't believe you would even consider this. Think safety!

tomf52 said:

There is no way this is a sensible arrangement, 15hp on a 10" john. In most states here in the east it is downright illegal. I can't believe you would even consider this. Think safety!

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Ok, educate me some more....Would this be a violation of a Coast Guard regulation, or would it vary from state to state?


WuzzFuzz

WuzzFuzz said:

Lakesider, I know of the Zodiacs, but aren't they V shaped in the front? Where as the Jon boat is square in the front...Other than that, is there any difference between a Zodiac and a Jon boat? I know on the Zodiac, those side are full of air. Then is the floor of the Zodiac flat? Or does it have some air in it too?

As far as my mattress goes, it would be squared off as a mattress is squared. And the front could probably be made that it would be up in the front like a Jon boat....What I didn't include with my idea of the mattress type of boat, it would come with a free roll of Duck tape for repairs, if a person hit a hidden log, or if a person happened to do a bad cast, and the hook got embedded in the mattress somewhere.


WuzzFuzz

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I was only joshing you with the Zodiac post!.

My definition of freeboard would be basically from the top of the water to the top of the side wall of the boat. With a boat like we’re talking about it might only be a few inches. Hope that helps, I’m gone for the night!

The 15 hp motor is out. I'm thinking 6 hp at most. But, I'm learning a lot from this post. Thanks for everyone's input.

I do think that my son's Landau boat is a little wider than some. The width is shown as 44". I found specs for an Alumacraft jon boat and it is only 32" wide in a 10' boat. I would think the extra width would add a fair amount to the stability and load carrying capability. If it sits low in the water, it's gonna be hard to push with a trolling motor. I'm still thinking 6 hp at most.

We just got the boat and I haven't seen it on the water. I need to see just how much freeboard this thing has when loaded. My son says it is "fine".

The more I think about it, the more I think a 15 hp may not be all that bad........














.........for a submarine.

Don't waste that nice motor! Trade up to a bigger boat.

blackdeuce said:

The 15 hp motor is out. I'm thinking 6 hp at most. But, I'm learning a lot from this post. Thanks for everyone's input.

I do think that my son's Landau boat is a little wider than some. The width is shown as 44". I found specs for an Alumacraft jon boat and it is only 32" wide in a 10' boat. I would think the extra width would add a fair amount to the stability and load carrying capability. If it sits low in the water, it's gonna be hard to push with a trolling motor. I'm still thinking 6 hp at most.

We just got the boat and I haven't seen it on the water. I need to see just how much freeboard this thing has when loaded. My son says it is "fine".

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44" across the bottom or across the gunnel (the gunnel is the top of the side). A .44" bottom would be fairly wide for a 10 foot flat boat-but since you said it was a 1044 that makes sense-10 feet with a 44" bottom. I am assuming that this boat is not going to be an expedition boat, that the guys just want to go fishing and putter (and I'll say it "drink beer").

As far as outboards-here's my take. First off they don't manufacture two strokes anymore so if you want a little bitty 2 stroke you will have to buy used which is a **** shoot. SO let's think new.
a 2.5 hp 4 stroke suzuki can be had for $699-weighs 31 pounds gopt a built in .27 gal gas tank which will get you an hour's worth at WOT. Carry a gallon container of gas with you and you've got all the range you need.
The 4 hp and 6 hp each weigh in at 55 pounds and costs $1137 & $1422 respectively and get .45 minutes at WOT with a .4 gal tank. The 9.9 weighs in at 87 pounds with no gas tank so you are gonna have to get a 3 gal tank and hose-more weitht and complications. It also goes for $2124.
Me-I weigh 250 and it's easier to shed weight by going smaller on the engine than drinking less beer. 10 foor boat picked up on the cheap-this is a no brainer to me at least-I'd go with the 2.5hp and bring along a gal of gas. Weight is important in a boat that small and it adds up QUICKLY. My f-in-law had a little 9 foot dink with a 2.5 on the back of it and my wife and I used to putt around Sabine bay or the back of Horn Island for hours sipping wine and just chillin!.
BTW I hope the bateau (we call them Bateaus down here "john boat" is what they call them in Arkansas) is welded and not riveted

Now if you want a REAL jon boat-you can buy a 16 footer from these guys in Jeanerette, LA (yes my home town ) http://www.metalsharkboats.com/specialty/16-resolute/

44" beam makes me feel a hell of a lot better about this whole situation. I was thinking it was one of the skinnier versions.

Cajun-that is a really nice rig on your link, more what I would call a "river sled" than a jon...slapping a 75 horse jet on that, and losing the Bimini top would be close to perfect!

-Klaus