Guidelines of going to a over the hub cleaver.

**conig** · 04-03-2019, 10:25 AM

I have a 14ft fiberglass john with a small V, running a 40-50hp johnson with a nitro gearcase. I am looking for a speed prop for sand bars and just messing around on lakes.

The boat has both setback and tilt and trim. The motor is mounted with the prop shaft just below the pad.

The boat is stuck at 40 with 20%slip. That is using a 19pitch sst prop just ticking the 6700rpm rev limiter.

I get 38 with a 19 pitch rapture and 35 with a 17sst.

I am looking to buy a 4 blade 18 pitch cleaver. Are there any standard rules of thumb when going over the hub?
The current props will not hold the bow.

I am hoping half an inch of diameter and another blade will let me lift the whole boat.

**David** · 04-04-2019, 07:10 PM

Cleavers lift the stern, not the bow, and generally work best at high prop shaft heights. Doesn't sound right for you, but one never knows.

**conig** · 04-04-2019, 10:19 PM

I feel similar but a lot of these faster jon boats I see are running 4 blade cleavers. Cleaver to lift the stern and trim to hold the bow. (Whole boat lift) I need something that will hold the bow none of these will in there current configuration.

I can get the 19 pitched to 21. Maybe have the barrel shortened to get some more lift on the rapture.

**powerabout** · 04-05-2019, 01:56 AM

boat sounds heavy, that nitro lower might not be helping, what ratio is in the nitro, it could be one of 2?

**FLATBTM** · 04-05-2019, 08:15 AM

Cleaver is what most of the bug buster and flatties down south use. How much this boat weighing?

Seems like that 19p should be pushing it a little harder. 50 merc on my 14' flat bottom was 41-42mph with a 16p.

Have you checked the bottom of the boat for hook?

**conig** · 04-05-2019, 08:17 AM

2.42 it's lower then the mercury's I am used to.

If I can get slip numbers down I am hoping speed goes up. RPM is good boat is roughly 350. I have moved weight around in a lot of ways. The rapture will lift the for a second or two and then lose bite when the bow falls.

Hoping for results like this and I can try a 4 blade cleaver at a reasonable price.

https://m.youtube.com/watch?v=opgFfW...ature=youtu.be

I have been told pitch doesn't change despite more blade area and exhaust flooding. Is that true?

**conig** · 04-05-2019, 08:51 AM

I couldn't find a hook. The lower gear case is huge as is the ratio. A similar boat was doing low 40's with a similar set up. Its heavier then a bug buster, its a kennedy craft clone

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**FLATBTM** · 04-05-2019, 08:52 AM

Yea that 2.42 is what skewed the numbers. 350 ain't to bad. That's what mine weighed.

You been on boat racing facts? Them Louisiana boys got a lot of info on these fast jonboats. I learned a lot over there.

**conig** · 04-05-2019, 08:57 AM

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The motor is 2 inches higher then this pic. Rpm goes up and slip goes up but mph doesn't.

**conig** · 04-05-2019, 08:58 AM

That's were I got the idea for a 4 blade cleaver but I am not a member there.

**99fxst99** · 04-05-2019, 09:20 AM

Contact Ron Hill Propellers, They used to make some performance props for smaller engines, maybe they can help.

**phillnjack** · 04-05-2019, 02:08 PM

whoever told you that is a nitro foot is telling you porkies, its just the normal foot for that motor. 9 nitro is 1.86 ratio and totally different in every way).
you have a 2.42 ratio and with a OMC sst 19 pitch on average will give you 40mph at around 5700 rpm and 6%. and 43 at 6,000 rpm.
your 35 with the 17 is about right, so is your 38 with the rapture... and what you are doing is getting about 6,000 rpm maximum.
you are not hitting any 6700 limiter...... those motors were not 6700 limited....... now what tacho are you using for this and what speedo ?

and drop that motor down so the cav plate is about 4 inches below the bottom of the transom,
that prop is no good running high and will slip like crazy... be faster the lower it runs.
I personally would drop the motor as far as possible to get better holeshot and max top speed.
and no a 4 blade cleaver on that motor and boat will not go fast. be lucky to get past 38
the rev limiter on these by the is 6100.

**conig** · 04-05-2019, 03:30 PM

I don't think anyone is purposely misleading me, but when i am asked what gear case, i give the year and model of the motor and they tend to say nitro. That higher ratio makes more sense for a hot foot.

I can take any of these props to a prop shop to be worked. My ideas are take the omc to 21 he said he could add cup. Or take the barrel down on the rapture. The rapture doesn't hit the limiter.

I am hesitant to cup the omc as it doesn't pull the tiller the rapture does. Which is ok as a play prop but i wouldn't want to fish all day using it.

I can lower the motor 2 inches but that's it without removing the cmc.

The omc prop has more rake then the rapture.

Tach is a tiny tach and it floats around 6100 but it has a delay. When looking at replacement powerpacks i saw 6700 listed for aftermarket ones, or i can buy one without a limiter. The motor does have 50hp carbs.

I am still curious about my original question do you run the same pitch when going from a through hub to over hub prop? What about chopper, the fast jonboat guys i speak to are all about cleavers.