Cheaper alternative to the $5000 Mercury CNC propeller

**mjw930** · 01-31-2019, 08:51 PM

Is the case diameter, it has nothing to do with the exhaust. The general consensus from more than a couple people I talked to who have direct experience with the 300R say the bottom line on the 300R is you need to run it 1” higher than a 300xs and need a 15.5” prop to get maximum efficiency and speed. They also said it’s not the same height and prop setup as a 400R due to the weight difference and torque delivery.

Randy’s observations comparing the 400R and the 300R on the same boat are fair but don’t take into account the weight difference. 180 more lbs hanging off the transom changes the CG and makes the rear run lower assuming the boat generates a fixed amount of lift at any given speed. The same boat running the same speed will have more boat, and by extension, motor in the water if it’s heavier, simple physics.

More than likely if the 300R was dropped an inch it could hook up the 32 Drag4 but that’s not the optimal setup as there would be too much drag when the proper pitch prop was used.

**WILDMAN** · 02-01-2019, 01:58 AM

That's incorrect. Even with 35 gallons of gas and 2 people in the boat, (which is way heavier than a 400R) the 300R will still not hook up with a prop under 15". I even forgot to raise the 300R above 1.25" the first time I put the first one in the water and it still would not hook up with a smaller prop. Also can't be the torque, because at 90 mph, torque would not still be making the prop slip. Just like a car with 800 hp is going to stop spinning tires at high speeds. The weight of the 400 has nothing to do with it either. Have you ever owned a 300R or 400R? You should buy a 300R and test it for us.

Originally Posted by mjw930

Is the case diameter, it has nothing to do with the exhaust. The general consensus from more than a couple people I talked to who have direct experience with the 300R say the bottom line on the 300R is you need to run it 1” higher than a 300xs and need a 15.5” prop to get maximum efficiency and speed. They also said it’s not the same height and prop setup as a 400R due to the weight difference and torque delivery.

Randy’s observations comparing the 400R and the 300R on the same boat are fair but don’t take into account the weight difference. 180 more lbs hanging off the transom changes the CG and makes the rear run lower assuming the boat generates a fixed amount of lift at any given speed. The same boat running the same speed will have more boat, and by extension, motor in the water if it’s heavier, simple physics.

More than likely if the 300R was dropped an inch it could hook up the 32 Drag4 but that’s not the optimal setup as there would be too much drag when the proper pitch prop was used.

**nitro_rat** · 02-01-2019, 02:11 AM

Originally Posted by WILDMAN

You should buy a 300R and test it for us.

**bor** · 02-01-2019, 02:05 PM

Originally Posted by WILDMAN

Well, I'll let all the "experts" figuer it out. All I know for sure is that on a 21 Liberator with a 300R, EVERY prop 15" and under slipped minimum of 20%. Now the 400R, set up on the same 21, at the exact same height, Pulled a 32 x 14.5 Drag 4 up to 7200 rpm at 108 mph. That is 11-12% slip. Same gearcase, boat, and height. Same prop on the 300R was on the limiter at 87 mph. That's 26% slip
That's my theory, and I'm sticking to it !!

thats no theory ! That’s real live personal experience! It doesn’t get any better to compare different props the way you do it , exactly the same setup back to back testing !

Great work and info !

**CUDA** · 02-01-2019, 06:02 PM

Simple Physics...

**oldschoolltv** · 02-01-2019, 06:14 PM

When I was a kid racing bicycles my grandpa asked a young kid at the starting line what gear ratio he was running, and the kids response was “I don’t know nothing about no gear ratio all I know is the faster I pump them pedals the faster I goes”.

**mjw930** · 02-01-2019, 07:17 PM

Originally Posted by WILDMAN

That's incorrect. Even with 35 gallons of gas and 2 people in the boat, (which is way heavier than a 400R) the 300R will still not hook up with a prop under 15". I even forgot to raise the 300R above 1.25" the first time I put the first one in the water and it still would not hook up with a smaller prop. Also can't be the torque, because at 90 mph, torque would not still be making the prop slip. Just like a car with 800 hp is going to stop spinning tires at high speeds. The weight of the 400 has nothing to do with it either. Have you ever owned a 300R or 400R? You should buy a 300R and test it for us.

Well, that’s information I didn’t have but the bottom line is we are all still working to figure out why the 400R can hook up a 14.5” prop and the 300R can’t on a 21 Liberator. I personally don’t think it’s exhaust, at these speeds the exhaust really isn’t ventilating the prop. Especially since half the exhaust port is out of the water.

What I do know is a lot of people had trouble propping the 400R due to its engine management. In one case, 3 different props on the same boat turning different rpms ran the same speed and Mercury’s response was engine management pulling power as it detects slip. It’s entirely possible the results you are seeing is completely different engine management strategies between the supercharged V6 and the NA V8. That’s one explanation that makes sense.

You have confirmed what Mercury Racing will tell you, the 300R needs a larger diameter prop than the 300SX. This Hill prop is a great alternative and certainly one of many that will pop up as time goes by. I wouldn’t be surprised if a 15.5” ProMax isn’t in the works. It would be interesting to see how these new props work on a 400R, I suspect they would work well. I also hear Herring is working on a prop specific to the 300R too, I’m sure they aren’t the only ones.

As to owning either, you know I don’t but I’m also not in the Marine business so I have little motivation to spend tens of thousands of dollars experimenting. If I was, I would.

I do appreciate the work you are doing, I didn’t mean to come off any other way. Just offering up opinions and relaying information I’ve gotten from other sources.

**Chaz** · 02-03-2019, 10:39 AM

Originally Posted by JPEROG

Supply and demand will always dictate market prices. As more guys step into the ring of making propellers that work for the new cases, there will be less demand for the original product. That being said, Mercury was the company that spent the time and money with their engineers to develop a propeller that would stay together and far outperform anything else out there-( now the world is going to follow). It would be interesting to know just how much money was spent in R & D along with the tooling cost for trial and error castings "my guess is that they have not made the money that everyone might think on this particular product".

Joe

Originally Posted by engineermike

It honestly shocks me how much anti-free market sentiment resides on this forum.

If Mercury is the only company putting a sticker on their engine that says "Racing" and all you could buy was an old Michigan aluminium wheel, it wouldn't be much of a racing engine. They had to develop props. Who became their competition in the in the aftermarket ??? Foundries and the hammer men that developed every prop in their line-up . How can they do that ??? Like everything else, Mercury likes to price themselves out of the game instead of being like WallyWorld and stacking the shelves to the point where X-employees say I would be a fool to try and compete with Goliath. Instead, they pave the way by creating a market, training the people to fill it and then all but abandoning the customer base.

Mercury came out with a wheel for 300xs motors on cat type hulls .. Have a sold a dozen of them yet ??? Looks like a worked over Bravo .. Yea me either..

Where's the Merc loyalty ????

Dewalt is the go-to guy there. This year $ 4000.00 a pair is what I was quoted.

From my understanding, Yamaha now owns HydroMotive and private sales are no more. Good reliable wheels, any size you want, but they wouldn't build true cleavers. They insisted on a hawkbill tip and 20* rake. Great for LCB's and STV's but seem to tie the azz end of a true cat down.

I bought a set of 5 blade Hill Signature propellors in 2012 @ Ron's suggestion. Grandfather to these I guess you could say. Another round ear deal, very efficient and I didn't have the power to pull them. He took them back and sent a set of four blade wheels. They were the right size, but ran 400 rpm apart. We checked them found that blade length, pitch and rake were right. But the blades had different cord width's (front to back length) I evened them out, and still have them today. for what I paid, and a little tune up .. can't say nuttin bad there.

I sent a deposit to Mike Quindazzi or Hill if you prefer in April for a pair of Buckshot 15x34x15 four blade cleavers. He told me a month. A few weeks in he called me and said they were having an issue with the left. I e-mailed Ron and he said he "stepped un his 14.5 a few times and it's still not 15 inchs yet" . And that cleavers never really held his attention much.
About 5 or 6 weeks in Mike sent my deposit back. I called and said I would rather have the props. he said .. If it ever happens we can start fresh. I thanked him, and said I noticed that for a guy who don't care much about cleavers, he sure is flee-bayin the he11 out of yours .. Mike's a sharp guy, he didn't need me tellin him that.
They seemed to jump right over the 15x34 guys and move into the 15.5 x 5 blade broached hub wheels. Nice looking piece ..

Randy what do they weigh ????

As far as 300R - 400 thing . V-8 power pulses, stroke, intake tract length add up to power delivery that doesn't give the blades a chance to stay hooked up. It's naturally aspirated, you'd have to be comatose for it to get away from ya ..

400 has traction control

I've driven enough blown alky dragsters to know that if your not paying attention, you can spit every bone out the bottom before you move ten feet ... Mercury's not gonna send out a screw blown anything without puttin a bridal on it first ...

**WILDMAN** · 02-03-2019, 12:02 PM

I just weighed and measured the props. CNC is 15.25" diameter and 14 lbs. Hill is 15.25 and 13 lbs.

**Risco** · 02-04-2019, 06:32 AM

Originally Posted by WILDMAN

I just weighed and measured the props. CNC is 15.25" diameter and 14 lbs. Hill is 15.25 and 13 lbs.

Thank you for all the information you provide. Glad to see your building more 25s this year always love that size

**Z06man** · 02-04-2019, 10:10 AM

We need to see if that 300R will hook up a smaller prop at 7000 RPM . Maybe that's the difference .. Just stirring it up .

**WILDMAN** · 02-09-2019, 02:14 PM

I can't name names, but I sold a customer a pair of 34x15.5 Hill cleavers this week. He has twin 400's on a 28ft cat, (not DW or Skater) and just ran 123 first time out with 38 lbs of water pressure. He said raising the motors should give him another 2-3 mph. He said they may be faster than his CNC props which ran 124 with almost no water pressure. He is VERY happy!

**mjw930** · 02-09-2019, 04:51 PM

I guess the next question is, has anyone run this prop on a 300XS and if so, what diameter and pitch?

**WILDMAN** · 02-09-2019, 06:50 PM

I'm getting the exact same props in a 4 blade next week to try on my twin 300xs 25 Liberator and a 4 blade 32 to try on a 300xs. They didn't seem to think they would turn the 5 blade. The 4 blade has the same blades as the 5 blade.

**MDRURY** · 02-09-2019, 10:42 PM

I would love to try a set of 5-blades on my Twin 300xs. Or have someone that has access to these props to try it. Still a lot of money for someone to gamble with if they don't work.
Will Hill let you try them before you buy? Or do you have to buy first, with the only one exchange allowed?

Randy, please try a set of 30" or 32" on your 300xs, that is the only way for any of us to know for sure if they will turn them or not. Without having to buy them to know.
Thank you so much for all your prop testing!!!!