How are y’all getting solid hub props to bite?

[RIVERRUMMER 70]

lol.....you dont get it ......why run the chopper if the boat wont perform....just bolt the motor to the transom up 2 holes and put on a good 19 or 21 std stainless and go 50..... period. have you even tried this setup? obviously your hull is not a havoc or edge or ambush and wont do what your trying to force it to do.
did you try to move the motor down like i said in my first post ....?
im sure the boat will do 45 with a std setup so why all the setback and high slip chopper with raised motor crap ? just to be cool?
seems like you just want to say "im running a chopper" ok have fun and good luck.

[97yamaha]

lol.....you dont get it ......why run the chopper if the boat wont perform....just bolt the motor to the transom up 2 holes and put on a good 19 or 21 std stainless and go 50..... period. have you even tried this setup? obviously your hull is not a havoc or edge or ambush and wont do what your trying to force it to do.
did you try to move the motor down like i said in my first post ....?
im sure the boat will do 45 with a std setup so why all the setback and high slip chopper with raised motor crap ? just to be cool?
seems like you just want to say "im running a chopper" ok have fun and good luck.

Yep, started on transom... porpoised and couldn’t turn 16p Yamaha prop. I’ll just put it all back and hope something has miraculously changed. All these 60+mph Jon Boat guys will be happy to hear that they can stop “acting cool”, sell their jack plates and solid hubs, bolt motor back to transom and pick up speed.

[phillnjack]

make a blow out ring and try it.

go and measure exactly the inside diameter of your gearcase where a normal prop goes in.
then go find a paint tin or something similar and cut to length so the prop is 1/3 inch away from it.
drill two tiny holes, one each side of gearcase and the can . put a bolt through the gearcase into the can and same the other side, put the nuts
on and go try it out.

if it work then get a nice alloy one made that is same on the outside as your gearcase and same on the front as the can to go into the gearcase so
it looks nice and neat, paint it or polish it and be happy.

if it dont work at all sell the prop and buy a prop that will do the job.

and raise the prop as high as you can, the deeper down the prop goes the more it will climb and put the bow down making it run too flat.

[97yamaha]

make a blow out ring and try it.

go and measure exactly the inside diameter of your gearcase where a normal prop goes in.
then go find a paint tin or something similar and cut to length so the prop is 1/3 inch away from it.
drill two tiny holes, one each side of gearcase and the can . put a bolt through the gearcase into the can and same the other side, put the nuts
on and go try it out.

if it work then get a nice alloy one made that is same on the outside as your gearcase and same on the front as the can to go into the gearcase so
it looks nice and neat, paint it or polish it and be happy.

if it dont work at all sell the prop and buy a prop that will do the job.

and raise the prop as high as you can, the deeper down the prop goes the more it will climb and put the bow down making it run too flat.

Thanks, That’s the plan. I’ve ordered the correct thrust washer for a chopper. The only OEM OMC blow out ring or “ventilation ring” I could find was for the larger gear cases to run the renegade props. Couldn’t find anything in a 3.5”. So I’m gonna make one this weekend. If all else fails, I’ll drill the lower or mid little at a time until I relieve enough exhaust to make it bite.

After asking around, a lot of these guys are running choppers with prop shaft 1/2” below pad, any higher without a low water pickup and they lose water pressure. So, I’m gonna go up with it a little more. None of them have the venting issues I have though.

[RIVERRUMMER 70]

Yep, started on transom... porpoised and couldn’t turn 16p Yamaha prop. I’ll just put it all back and hope something has miraculously changed. All these 60+mph Jon Boat guys will be happy to hear that they can stop “acting cool”, sell their jack plates and solid hubs, bolt motor back to transom and pick up speed.

they have better boats than you..... sorry your mad bro.
what is max hp rating on your hull and what mfg? i cant believe it wont go 44 mph with the motor up two holes and a good thru-hub "stainless" prop. did you try mounting it up 2 holes on transom? you never said what you tried in detail so how do we know what you have done? i would also ck leakdown on that motor, 50 hp on a 15' alum boat should run like a scalded cheetah.
slipping an 18" 20% is the same as running a 16" 10% without the other assoc problems. i would think 7% could be realistic slip with these riggs.
many of those utility boats have hook rite at the transom like a lip to help them stay flat with lower hp and a load in rear of boat.
are there boats like yours performing in this now 60 mph range? exact same hull and mfg or are you assuming it should perform the same as these other hulls?
remember were talking about your boat not theirs. trying to help but it may be futile at this point.

[RIVERRUMMER 70]

Thanks, That’s the plan. I’ve ordered the correct thrust washer for a chopper. The only OEM OMC blow out ring or “ventilation ring” I could find was for the larger gear cases to run the renegade props. Couldn’t find anything in a 3.5”. So I’m gonna make one this weekend. If all else fails, I’ll drill the lower or mid little at a time until I relieve enough exhaust to make it bite.

After asking around, a lot of these guys are running choppers with prop shaft 1/2” below pad, any higher without a low water pickup and they lose water pressure. So, I’m gonna go up with it a little more. None of them have the venting issues I have though.

pad? what pad .....jon boats dont have pads, if these other boats have pads thats the diff ....weld a god damn pad to the bottom of your boat and then you can start running 50. wow i just figured it out. do you know what a pad is?

[97yamaha]

they have better boats than you..... sorry your mad bro.
what is max hp rating on your hull and what mfg? i cant believe it wont go 44 mph with the motor up two holes and a good thru-hub "stainless" prop. did you try mounting it up 2 holes on transom? you never said what you tried in detail so how do we know what you have done? i would also ck leakdown on that motor, 50 hp on a 15' alum boat should run like a scalded cheetah.
slipping an 18" 20% is the same as running a 16" 10% without the other assoc problems. i would think 7% could be realistic slip with these riggs.
many of those utility boats have hook rite at the transom like a lip to help them stay flat with lower hp and a load in rear of boat.
are there boats like yours performing in this now 60 mph range? exact same hull and mfg or are you assuming it should perform the same as these other hulls?
remember were talking about your boat not theirs. trying to help but it may be futile at this point.

Eh, this rig has just got me salty to begin with man, because I know it should be performing better. It’s a “commercial” grade Weldbilt 1548 semi V, so it supposedly doesn’t have a HP rating, but the non commercial version is 40hp rating. It’s an 0.080” Aluminum hull so it’s a very light hull, and I dunno how it got a “commercial” badge being that light.

I realize it’s not one of your premium duck boat brands, but in the duck boat/Jon boat community, these hulls are supposedly very quick... that was my purpose for buying. Before there were all these performance duck boats, they use to use these hulls as go-fast river jons. Gene Anderson, Caleb Mitchell, Kent Foreman, and a few more from the duck boat community have gotten these hulls over 60 and even 70... Granted they’re running those ported 40hp Mercs. Most of them race and are kinda secretive with their exact setups. From pics I can tell most are running 8-10” of setback with solid hub props.

With that being said, I’m not trying to do 70 or even 60. I just wanna outrun some of my buddies down here on the pearl river.

It had a hook in rear when I bought it, but I straightened it. My motor is 2009 50TLR and has 125psi on all 3 cylinders (as of about 2 months ago). Initially I hung the motor on the transom, and with a 14p Stilleto, I got 35mph. Once I mounted a Vance 6” jack plate and lifted the motor a couple inches I got 41mph out of the same prop on the rev limiter, which seemed very promising since that calculates to be very little slip. So I went up to a 15p and slowed down somehow. Been battling with it since. Boat always seemed to run VERY flat and couldn’t get any lift, even with medium rake props like the Powertech SRD. So I figured the high rake chopper could give me the lift I was looking for, and it did, just slipped and vented really badly, which is why I’m here.

Here’s a link to the same boat, I think this is Gene Anderson.
https://youtu.be/IqUo-PIV3cI

[97yamaha]

pad? what pad .....jon boats dont have pads, if these other boats have pads thats the diff ....weld a god damn pad to the bottom of your boat and then you can start running 50. wow i just figured it out. do you know what a pad is?

Sorry, used the wrong word, just meant bottom. Those manufacturers made a couple padded hulls but most are not padded. However, I do have plenty of spare Aluminum laying around and have thought very seriously about welding a pad on. I just feel like that’s an extreme measure and this hull should be capable of 50 without a pad.

[RIVERRUMMER 70]

go to havoc website and watch that video and tell me what you see on 90% of those propshafts ...... first 3 min of video when they are putting boats in water.

[97yamaha]

go to havoc website and watch that video and tell me what you see on 90% of those propshafts ...... first 3 min of video when they are putting boats in water.

Probably thru-hubs.

[PPRINT]

97yamaha,
I just went through a similar exercise on my flat bottom boat but looking for the opposite results. I was looking at running as shallow as possible with no regard for speed. Weird application that involves red fish and 8" deep coastal back lakes.

Point is, what I learned is choose a prop builder that knows the market you are in and do exactly what they say. If you ask around at one of these meets about who can build you a competitive prop you will get a direction to go with your quest.

I watched some fast flat bottom duck boats on youtube last night and I will say you are correct...those are some ported motors. They sure aren't out of the box 40hp motors. i don't dare to guess how high they reving these motors, but what ever it is they are still making great power up there.

I know all the calculators say you should be able to do it with this and that prop, but none of those calculator take into account hull drag. As you are finding out, some hulls are better than others.

I am sure hoping you will keep this thread updated as you work through this challenge. We will all learn a thing or two.

Rob

PS, I agree with all the comments about getting a thru hub exhaust. Not only are you fighting the exhaust induced ventilation, there is a good chance you are fighting surface water ventilation also. Especially on the transition getting up on plane and again at top speed. Ask me how I know....see above about my application. That water coming off the back of a flat bottom jon boat hull is not as clean as it looks. BTW....cup fixes it. Not just on the tip, but in the blade shape itself.

[phillnjack]

DONT forget a lot of those of those with super fast merc triples are also running NOS and getting over 8,000 rpm !!!!!
those camo fire extinguisher's are realy blue bottles in disguise.

[RIVERRUMMER 70]

Go to my post #11 read it slow and be open minded ......please try it.
If your on limiter you can go down and give it a little more bite and see what happens ...how hard is it to move the motor down a little?
Run it 2" below bottom and see what happens. Don't change anything else.
Then sneak back up if it wont rpm .125 -.250 at a time .

[97yamaha]

Update guys: ended up drilling the lower to relieve some exhaust. Shaved down a Merc thrust washer to match OD of prop barrel. She gets on a plane fine now. After messing with the engine height I managed to squeeze 46mph out of it on the rev limiter of the stock 50. I’ve got the aluminum to add a pad soon, and after the engine mods I’m working on and a pad, I’m hoping to hit mid 50s.