12' Jon Boat Won't Plane?

[Fishfinder13]

I have a 12 foot semi v aluminum jon boat. This boat has a 2008 6 hp Mercury four stroke on it. When I go out I take the gas can, 2 poles, a battery, trolling motor, and 2 people. People are normally 160lbs and anywhere from 100-150 lbs. This motor tries so hard to plane the boat but I just can't quite get it there. I purchased a doel-fin for it but realized it will not fin on 6 hp Mercurys. Does anyone have any suggestions on how I can get it to plane? Thanks, Fishfinder13

 

[jestor68]

Re: 12' Jon Boat Won't Plane?

What does the boats capacity sticker say for HP, people, weight?

Make sure the motor's title/trim pin is set in the first hole, closest to the transom. If the motor is tilted out too far, it will have more trouble getting any speed up.

 

[Frank Acampora]

Re: 12' Jon Boat Won't Plane?

You are asking a LOT from a four cycle 6 HP engine. Four cycle engines just don't have the same torque at low speeds as a two cycle engine, thus, they may have trouble under load, breaking out of the "hole" onto plane.

Try the engine with only you and no load in the boat. If it breaks over onto plane then you know that you need either a two stroke or a larger horsepower engine.

IF--and that is a big if, if you can find a selection of propellers, a different pitch may help. If different props are available, go over to the prop forum and ask there.

 

[jestor68]

Re: 12' Jon Boat Won't Plane?

A quick search shows only 2 props available; a 7 and an 8 pitch.

 

[Fishfinder13]

Re: 12' Jon Boat Won't Plane?

It is rated for 3 people, 550lbs (people, motor, and gear) and a 10hp outboard. The tilt is currently in the 4th pin up from the transom. The prop on it is a 7.8X8

 

[cyclops2]

Re: 12' Jon Boat Won't Plane?

9.9 IF the hull is a deep one. Not a shallow 15" one. Also called a short shaft.

My short shaft Lowe Alumimum 16' has a Evenrude 9.9. It barely planes with my 220# & LOTS of gear on board. Is the bottom covered with growths of weeds & slime ?

 

[Fishfinder13]

Re: 12' Jon Boat Won't Plane?

If you are talking about the bottom of the water I'm running it in, I am running it in the bay. Usually flats fishing for snook and redfish in it. So yes, there are weeds on the bottom.

 

[cyclops2]

Re: 12' Jon Boat Won't Plane?



I am asking about the bottom of your boat. Stuff builds up fast on the hull bottom & really can slow down a boat.

 

[Fishfinder13]

Re: 12' Jon Boat Won't Plane?

No it is washed down with fresh water after each use. No slime or weeds

 

[moi]

Re: 12' Jon Boat Won't Plane?

Don't think that rig will plane with that load and just a 6 hp four stroke.

BTW, I never heard of a semi vee jon boat. ???? What am I missing?

 

[nwcove]

Re: 12' Jon Boat Won't Plane?

jmo, a 6hp 4stroke would be doing well to plane your boat , with just you and the gas tank aboard.

 

[cyclops2]

Re: 12' Jon Boat Won't Plane?

The bow does have a slight V to it. Boat is usually flatbottomed most of the length. Any V does eat up some more power to get up on to plane.

Do you plane alone easily ?

 

[Fishfinder13]

Re: 12' Jon Boat Won't Plane?

My boat is mostly flat towards the back but the front and middle slope down to a V. Unfortunately, I have never been on it alone. I want to try that though.

 

[Fishfinder13]

Re: 12' Jon Boat Won't Plane?

I have had people suggest I put trim tabs on it because it is almost there with a LOT of weight. Also, the original owner of the boat had some kind of fin on the motor but the holes are very close together. I'm guessing it was not a two piece doel fin. Anyone have any ideas?

 

[steelespike]

Re: 12' Jon Boat Won't Plane?

A 6 is rated for about 12-14 mph with light reasonably fast boat. Needless to say your well removed from that.
We had a flat bottom steel boat that would pop on plane instantly with a 180- pounder and a tiller extension.
Go with the 7" prop. Also normally a boat will plane easier with the motor trimmed down,(prop closer to the boat).
when alone you will need to move the gas tank to the bow and you may need a tiller extension so you can sit in the middle seat.
Is the anti vent plate(just above the prop) about even with the bottom of the boat?
You would possibly actually do better with a big bare bones 14 or or even a 16.

 

[jigngrub]

Re: 12' Jon Boat Won't Plane?

The tilt is currently in the 4th pin up from the transom.

... and there's your problem, or part of it. The motor needs to be tilted all the way down for power.

 

[Grub54891]

Re: 12' Jon Boat Won't Plane?

You need a bigger motor,my 12 ft John goes like crazy with just me, add a couple people and gear,it's like trying to get a whale up on plane,I'm running an 8 horse,I need a 10!
Grub

 

[Sea Rider]

Re: 12' Jon Boat Won't Plane?

If that's a rebadged Tohatsu you could be experimenting tail drag issues which inevitably will slow you down more if hull shape it's not doing so already. Trim engine to be perpendicular to boat, move yourself towanrd bow full throttle with extended arm and see what happens. It's a pity that the 6 cannot be updated as it's 8 HP older brother, has more CC tham the 6. If it would be a 2 strokes, could easily pass it to a 9.8.

Happy Boating

 

[airshot]

Re: 12' Jon Boat Won't Plane?

Yep...you got to face the facts, that 6hp 4stroke won't do it.... I have a 12 ' with a 9.9 jonny 2 stroke and it flys even with two people. GPS shows 22 mph by myself. The 4 stroke is much heavier and much lower on torque, and the torque is the snap you need to get up on plane. Your 4 stroke is much more fuel efficient but no where near the performance.
You can add all the gizmos you want but it ain't gonna happen with that 6hp. Sorry for the bad news.

Airshot

 

[roscoe]

Re: 12' Jon Boat Won't Plane?

And then there is the fact that some small boats just won't plane, unless you overpower them to the point of boing unsafe.

You have 2 options IMO. Settle for what you have, or think about spending money on either a bigger motor, or a different boat and motor.