My son recently purchased a nice Landau 1044 jon boat. It came with a like new trolling motor and battery.

He thinks he needs a gas powered outboard for crossing a large pond or small lake.

The boat is conservatively rated for a 3hp outboard. I think a 4 to 6 horsepower motor would be fine. But, he found a nice 15 horsepower Mercury locally for a good price. It weighs at least 60 pounds more than a 6 horsepower motor.

Do any of you have experience with this type of situation? What would happen if we put a 15 horsepower motor on the boat? My son can weld aluminum, so we could reinforce the back of the boat.

Weight gets to be a concern as well. My son weighs about 180 and his fishing buddy is around 250.

WOOHOO!!!!!


He may want to think of filling the seats with Styrofoam, or something else cause if the weight distribution aint just right, or if he hits a log/nutra/ect at speed that flat bottomed boat is gonna sink like a stone.... he will have a LOT of fun with it otherwise.......

In all seriousness, if he can keep his fishin buddy up forward, (and be VERY careful with the throttle) he will probably be ok with it.... and he can always trade it for a smaller sized motor when he discovers its waaaaaay overpowered

I used to have a 14 ft. aluminum john boat it was rated for a
10 hp motor .I ran a 7 1/2 hp on it . I'd say that the 15 hp is going to be too heavy IMO.

I think that between the two of them, gear & outboard, there's not going to be a lot of free board...

Just my .02

I'd say weight is going to be the problem. A lot of small outboards have a built in gas tank (at least they used to). A 15 is probably going to have an external 3 or 6 gallon tank. That's even more extra weight than just the engine.

I'd look for a smaller outboard.

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John 3:16 .

I had a 7.5 on a 12 foot trihull glass boat, that thing would jump up on a plane real quick and flat get with the program! That 15 would certainly keep things interesting!

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Even older, even crankier....

The weight of the motor and driver in the stern may make it sink. If it doesn't, there's the chance that when taking off the boat will stand up and flip over. If all this doesn't happen then the game warden or lake patrol will likely write your son a safety citation.

10 foot jo boat??? he needs to find a friend about 70 pounds lighter.
I'd stick with a little 2.5 hp-they don't need to be putting any more weight in that boat no.

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Forum consigliere

He is considering an outboard that is 5 times the power the boat is rated for? This is nuts and illegal. If he is stopped by conservation police, he will (and should) get a ticket and a fine. If he has an accident with this outfit he may get sued. The boat should have a tag on it that shows maximum legal horsepower and maximum weight which includes people, engine, fuel, gear, every[thing on board. I can't imagine a 10 foot boat would handle the type of weight you are talking about.

Thanks for the input.

I've read conflicting opinions on the internet. That's why I posted here. Some guys say it's o.k. Others think it's crazy. I hadn't found anyone say that it was dangerous, or illegal, or I would have squashed the idea already. The biggest reason he is considering an oversized motor is because he may move to a bigger boat later. But, if it isn't safe, it isn't going to happen.

We had a state park ranger tell us that we wouldn't get ticketed for running a motor larger than recommended for the boat. He was trying to sell us a 6 hp motor, so he might have been telling us this so that he could sell a motor.

Sounds like we need a bigger boat, but I don't have any place to keep a boat with trailer. The jon boat is small enough that it fits in the back of our El Camino and we can carry it into the back yard for storage. We might get a 12' jon boat to work which gains us quite a bit in terms of weight capacity.

I have no sense of what a 4 to 6 horsepower motor would do for that boat. I had a boat motor salesman tell me that a 3 horsepower motor wouldn't be much faster than the electric trolling motor. There's no real gain to that. Would a 6 horsepower motor propel the boat well?

This is one of the few times when I would disagree with Tim "the tool man" Taylor and suggest "more power ain't the answer". I don't believe the tiller/prop would accurately or safely steer the boat with all of that torque and power. Especially only 10 foot long with, I'm sure, a very narrow beam (even with 450 pounds of "dead weight" aboard).

He might find himself spinning in circles out in the middle of the lake because of torque steer.

I'd absolutely pass on 15hp in this case. YMMV!

If he goes ahead with the 15 hp motor PLEEEAASSE take video and post it here!!!!!!!!!

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paws for friendship

Bad idea for all the above reasons, not to mention that thing would be so dang unstable and squirrely.

A C.O. would ticket them for sure if they were spotted.

How about a 426 Hemi in a PT Cruiser? Maybe 3 tons of 22 LR in the back of your 150 / 1500 pickup truck?

Your son and his buddy excede the load capacity of that boat without a motor, fuel tank, or fishing tackle.

I had a 14' jon boat I hauled in the back of my Ford F150 standard cab pickup with a 10 HP outboard on it. Motor, tank, fishing stuff, and two adults exceded the max load of that boat by 150#. When I was driving and Earnie sat in the middle, we had 2" of freeboard (top of boat to top of water) just before I put the motor in gear. When we got on plane, we had about 6" free board. When we fished, I was in rear seat, Earnie was in front seat, and we had 4" freeboard maybe.

NO, NO, NO ! ! !

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S&WHF 366

I think we'll keep looking for something in the 4 to 6 horsepower range.

Thanks for the input!

Just plain DANGEROUS. Make sure to wear the kill switch at all times, because you will be in the water and don't want the boat coming back to get you.

I have had a 15 hp Mercury for years on a shallow 12 foot aluminum boat that was rated for 15 hp max. One calm day, 3 people were in the boat and for no apparent reason, it torpedoed without notice. I think is was too much weight forward, but it remains a mystery. This is something you do not want to do during a cold duck season return trip to the launch after dark. I immediately bought a new deep hull boat with a 30 hp rating and 3 times the capacity rating. I love it and the 15 hp is perfect.

Bottom line is a 10' Jon boat is inherently unstable and is dicey even without a motor and only one person and gear in it. Only thing worse is a pirogue, but that is another story.

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Gary
SWCA 2515

I used to get lambasted by all the ninny's and Coast Guard Aux in the past. I'd just bought a little flat bottom Checkmate with a 140 on it. It was made prior to them putting a CG approved HP on the number plate. Well, I fried the 140 Merc and put on a 155XS. And that really set all of them off about how unsafe it was, etc. I finally got a bellyfull of the idiots and borrowed a wraparound from a friend's 115. Then everything was just great. Except the fool watercraft officer who decided his mission in life was to inspect me and the boat everytime he saw me. But watercraft officers don't have sirens, just little lights that flashed. And somehow I never noticed him falling back in the distance. He insisted I should stop for his nonsense anyway. But I agreed I needed to be inspected once a season. So when he got wise and just parked his boat at my harbor a buddy just pulled my trailer across the river and we loaded it up. Then quietly pulled it back to the harbor and parked the thing. It was part of what biased me against fool cops, watercraft or not.

So what I say to the OP is to suggest a test. Get the advertised weight of the proposed engine. Then just launch the boat and keep adding concrete blocks to the stern. See how it looks. Then have the son and fishing buddy get in. OK, have them wear life jackets!

I don't worry about too much HP. More is better, too much is just right. You've got to learn how to feather the throttle. You're right in the efficient operating range. Two stroke engines tend to suck fuel wide open. At part throttle they sip it. Going faster than the other guy isn't all that painful.

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Dick Burg

A 15 hp motor is too big for that boat.

Sell the 15 hp and get something appropriate.

Back in the 1940s. My grandfather had a old heavy wood 14 foot boat with a sears 1 1/2 hp motor that we used on Candelwood lake in Danbury ct. The prop was like 2 tablespoons, it pushed the boat at about 3 miles per hour. It was a lot better than rowing. Stay with a 3 hp its fast enough for fishing and a lot safer.
good luck

10ft jon boats are unsafe to begin with, use the trolling motor or row it.

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Don

I think this is more of a consideration of weight more than it is power. 60 pounds isn't much but in a 10 foot boat it's a lot considering two men and gear. A 4, 5, or 6 HP should be sufficient.

Just my opinion as I don't own a boat. Boat my dad had when I was a kid had a 350 Olds inboard!

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Life Is A Gift. Defend it!

I have had 12 and 14 V hull aluminum boats with 9.9 and a 15HP. In those days the blocks were the same for the 9.9 and 15, just different bore and carbs. The 15 HP would scare the heck out of you with one person in the boat.

Jon boats are not made for planing and high speed.

The 10ft Jon is not rated for a 15HP it would be foolish and as others mentioned you probably would get cited.

Also depends on if it's 2 or 4 stroke. the 4 stokes are heavier.

Forget it!

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Still Running Against the Wind

I used to have a 12' jon boat and a 3 1/2 moved it pretty good. Of course a modern 10 HP probably wouldn't weigh much more then my old 3 1/2 HP Scott.

A P.S. here. Does the boat list a load capacity on the tag? If it doesn't, call the company that built it with the model number and ask them. Remember you have to add everything that you are putting in the boat.The one spec I could get off the net was that the boat weighed about 75 pounds. If this is correct it isn't going to be built very sturdily. I'm not sure you will even be able to put a 3 on it with the weight of your son's buddy. You cannot overload the weight capacity. Many 3 hp engines will weigh about 40 pounds. 15 hp engines will weigh about 100 pounds. Don't forget the gas tanks and fuel loads.

I think I would buy the good priced motor and start looking for a bigger boat.

Wingmaster

I would NEVER even consider such a idea!!! You are also asking for a violation ticket , by overpowering it . Remember that original HP rating is from the US Coast Guard. It is not the recommended power it is the MAX. allowed power. If you went ahead and mounted it I can assure you that the boat will be unmanageable and downright scary, that is if you could get it to not swamp outright. I`d buy that nice motor and then sell it for a profit to buy the correct size engine. Good luck .

If he can get the Merc for a good price it's probably time for a bigger boat.

He's got the bug.

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Dum vivo cano

The last time i saw a rig similar to this but with a smaller motor they were launching in Sabine Lake with about 2" freeboard. About 30 minutes later we heard hootin' and hollerin' and saw 2 heads and an ice chest. Unless it is a 10 ft deep and wide I wouldn't trust it in anything but a small pond or creek/bayou.

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KMAG YOYO

One other piece of gear I would add to that combination would be a periscope. All submarines should have one.

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S&W Armorer
Lost in the 50s

Fifty years ago, when I was young and broke and stupid, I bought a ten-foot johnboat. It was all I could afford and it could be carried on top of a station wagon.

My brother and I (he was even younger and just as stupid) fished from it a lot. We each weighed over 200 pounds. With our fishing gear aboard the boat had about 3/8 of an inch of freeboard. Okay, that's a slight exaggeration, but it was damned perilous. It was even a little riskier with the additional weight of a trolling motor and battery.

It might, just might conceivably have handled a three-horse motor. A fifteen horsepower job would have rendered the craft a kamikaze rig like those Japanese suicide torpedoes, only slower.

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Oh well, what the hell.

In my youth we put a friends 10 horse Evinrude on a 10 foot Arkansas Traveler john boat. In lake Tahoe Ca. It was a lively, sporty combination on or shake down voyage, skipping like a flat rock across the lake. Really had to feather the throttle to get it to turn.
On the second try it caught an edge, rolled, and tossed two bikini clad hotties into the lake. What were we thinking letting two bikini clad hotties play with our new toy? You know what we were thinking...

Oscar Zulu

That's an accident waiting to happen.

John

You're gonna need a bigger boat.

Please take a video for YouTube! Should be a good one.

Thanks for all of the input! It's been good reading.

The 15 hp motor has been ruled out. I'm leaning towards a 3.5 hp motor.

Get the 15 HP then go trade the boat for at least a 14 footer. If you have ever fished out of a 10 footer it is something scary to say the least. My uncle dumped himself twice with his and that was getting in and out of the boat at the bank. Also I have ran a 3 horse air-cooled back years ago and it would require paddling to make any headway against a not so bad of a wind.
If he is going to do anything other than puddle fishing, I would strongly recommend a 14, with at least a 36" bottom and a 10/15 HP motor. Been there, done that.
Larry

Time for a bigger boat.
I wouldn't be surprised if the thing didn't sink before they could get the motor started. Really....

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In dog years I'm dead.

Howdy,
I'd jump on the motor and look for a 14 foot boat. He would be better off all around.
There isn't much freeboard or room in a 10' boat to begin with.
Best of luck
Mike

Here is a short video I shot last Fall of my 14 foot V-hull boat being driven by my 6HP outboard at full throttle. It is plenty fast for tooling around the salt ponds duck hunting. By the way, this boat is rated for a 10HP motor.

https://www.youtube.com/watch?v=2Ce0...ature=youtu.be

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?

To expand on this, there is a reason for the 9.9 hp designation. On some inland lakes motors 10 horsepower or above are not allowed, so a 9.9 horse came about by simply detuning a 15 to conform to the regulation. So, if he hasn't done so already, the OP may want to consider where the boat is being used before he decides on the 15, even if he is to put it on a larger 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.

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14 S&W Revs none with locks!

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

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TEXAS, by GOD

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

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

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14 S&W Revs none with locks!