# Top speed with small motors



## santander (Jan 18, 2008)

I have been running my new to me 8 hp johnson on my little jon boat and was wondering how it compared to top speeds on other small boats. I'm don't have any jack plates or hydrofoils and i'm running about 19 mph on gps. If i got a hydrofoil would i get any increase in speed? What speeds are you guys running on motors under 10 hp? Is the flat bottom more efficent or less than a v shaped bow? I would like to find out what boat you have, what size motor and how fast your going.
thanks


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## Guest (Jan 25, 2008)

I owned several jon boats for rent for surveying and commerical work and a mosquito survey jon boat with from 8hp 4-stroke to 25hp 2-smoke.

1436 tracker jon boat with 9.9 mercury 4-stroke and manual jackplate top out 24.1 mph gps.

1436 G3 with 9.9 mercury 4-stroke with custom powertech 9x7.5 4 blade prop and manual JP tops out 20 to 21 mph.

1436 G3 with stock 15 merc 2-smoke with no jackplate top out 25.3 mph

(6) 1436 G3 with 8hp merc tops out 16 to 18 mph.

Alll flat-bottom jon boat runs skinny everywhere...canals, creeks, ponds, backlish water. Marshes and lagoons.

Hope it helps.


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## costefishnt (Dec 11, 2006)

19mph on a john boat with an 8h is pretty good. I had an old johnson 6h on a gheenoe and top speed was @14-5mph. The flat bottom is efficeint in the fact that it takes slower speeds to plane rather than some of the v-bottoms. once the boat is up on plane, all boats have a pad which is where the boat sets on plane. which boat is more efficeint is something the more knowledgable folks will have to address.

Hydrofoils, sting rays and the likes have different effects on different boats. I can not give examples for all, but on a gheenoe with a 15 h no jack and no offset I lost almost 2 mph with this addition, however I did gain better stability and lower planing speeds. I know of another persson who had nearly the same set up as i who tried the same hydrofoil and actually gained about 1mph.

With teh speed you are getting, other than playing with props i think you might be about topped out. 

hope this helps in some way.


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## boggob (Feb 20, 2007)

I get 17mph with a 9.9 Merc 2-stroke on my highsider loaded with 2 guys, gear, battery and trolling motor.


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## santander (Jan 18, 2008)

thanks for the replys, when i tested i was by myself with all my gear including bow mount TR and battery, so i figure with 2 people i would be going around 15 mph. I was suprised how easily the boat gets on plane, normally at 1/4 - 1/2 throttle. I was going to get a 9.9 or 15 hp because i didn't think anything smaller would get me on plane but i'm happy with the 8, plus the motor only weights around 50-60 lbs. A 15 might be a little scary at wot on my little boat.


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## Ron_W. (Dec 14, 2006)

Sounds like your running pretty good. If the boat was planeing bow high then a hydrofoil on the motor could level the boat and let it run more efficiently and possible faster.


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## deerfly (Mar 10, 2007)

if I remember correctly my 15-4 hi-sider with a 5hp mariner topped out around 14mph


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## Garry (Dec 14, 2006)

The 13 foot gheenoe I had with a 9.9 Johnson did 23 mph with me, Tm, batt., and gear. 19/20 mph with 2. I also added trim tabs on it also that helped out alot.


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## fishindad (Jan 25, 2008)

I have a 4 cycle 4 hp merc. Looks like from what I am reading here, this will have a real potential to help my situation out. With the 4hp I really dont get up on a plane. Looks like this may solve that problem. Cool!

Fishindad


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