300R V8 - Prop Selection

[triplenet]

Morning guys...... Just hung the new motor on an Islamorada Boca with jack plate.... Slapped on a used Fury 25P 3 blade.... Ran her to 68 MPH at around 5800 RPM.... Could have possibly squeezed a few more RPM with more trim...

Any other suggested props that dont break the bank? I run in skinny water in the Florida Keys so always in sand/mud/etc... Dont want to ruin a 2k prop ...

Thanks !!! NNN

[Radiant]

Try out a bravo. Good all around prop

[engineermike]

What lower unit?

[mjw930]

Optimal performance with the new gear cases will require a 15” or larger diameter prop. Also note You won’t get to redline regardless the prop until you get past at least 2 hrs on the motor and it will depend on how many of those minutes are under load.

[Pulsare2400]

I have tried about 5 props on my 300R. So far the best overall was the 24P Bravo 1 FS, turned 6200 at 72 mph. A new 24P Solas Scorpion turned 6000 rpm at 71 mph (I have it for sale for $350 with the hub and it only has 15 minutes on it). I will consider trying a ProMax later in the year. The Bravo is 15.25" dia. and the Scorpion is 15.125" dia.

[engineermike]

I’ve run promax, bravo1, Maximus, p5x, and max5 on my hd sport master. I’ve found that the 5 blades all worked better than the 4 blades, and that maximizing engine height unlocked speed. Bravo1 was the worst on my boat.

[Pulsare2400]

Engine and boat combo will make a lot of difference as will the height like you mentioned. The Bravo 1 was 2 mph slower than the Bravo FS. The 5 blade was too small in diameter and only 23P so I ran it up on the rev limiter. Likewise for the 24P BBlades Blaster it ran way over the rev limit. The Bravo FS had 8% slip at 6200 if you use 23.4 to calculate the pitch and 10% of you use 24" to calculate the pitch. Did you try a Bravo 1 or the newer FS or XS Bravo props? How much faster was the ProMax than the Bravo type you tried? I am also considering to try 5 blades. At 3000 rpm if I had the prop shaft 3.5" below the speed was 24 mph, if I lowered the engine another 0.5" the speed went up to 30 mph and the rpm stayed at 300 rpm. I ran the WOT run at that prop height. I will have to go back and bring it up to 5000 rpm and then raise the engine at that speed to determine if the slip is less and I can run more engine height at high rpms which would make sense. Too early for me to make comments supported with sufficient facts, but I am not impressed with the 300R yet, but hopefully that will change.

[mjw930]

From what I’ve read, heard and experienced, the best performance is coming with 5 blade, 15.25” diameter Max5 ST’s and Hill Signature 400 cleavers. Almost everyone has said they could not get most other props they had used with the Opti’s to work well. The base setup that Mercury and others have said is a must, 15.25” or larger diameter prop running 1” higher than 300XS SM setups. From there it’s just fine tuning. Supposedly this holds true for cats and V’s. I have not seen any data on TM lower.

[engineermike]

..... The 5 blade was too small in diameter and only 23P so I ran it up on the rev limiter.

Sounds like you tried a High5, which I would never recommend on an HDSM due to the 13.x” diameter and lack of blade area.

. Did you try a Bravo 1 or the newer FS or XS Bravo props?

3 different pitch Regular bravo1s. My understanding is the FS just lacks vent holes and xs is just a shorter tube.

How much faster was the ProMax than the Bravo type you tried?

On my boat promax was literally about 14 mph faster than bravo1. Blaster ran decent on it as well though. But neither promax or blaster could touch a max5.

I am also considering to try 5 blades...

That would be my recommendation. Max5’s are great but p5x might be right there. I’ve wanted to try an sl5 but can’t seem to find one to mess with. Then, of course, there’s the cnc props...

[mjw930]

Then, of course, there’s the cnc props...

or the Hill 400 5 blade Cleaver. It’s basically the same prop as the CNC for half the price. I’ve heard great things about the Max5 ST too but Mercury is very proud of that prop $$$$

[Pulsare2400]

It was not a High 5 but the Hill Pleasure 5 blade only had 14" diameter. It was on the rev limiter hard so if it would have been 24 or 25P it would actually have done not bad. How did you run 14 mph faster with the ProMax? The Bravo must have been slipping bad on your boat or on the rev limiter? I was surprised how bad the Blaster slipped on my boat.
I have also been looking for a Hill Signature 5 blade but I think the smallest pitch is 26P, not sure if I can turn it and would have raise the jack plate to the max to help out. That prop is much cheaper than a Merc Max5ST. In fact you can almost spend $2000 on the Max5ST so you might as well buy the Hill 5 blade CNC cleaver for a couple hundred more. I think that over the hub prop will slip bad coming on the plane like the Blaster did.

24P Bravo 1 FS – 6200 rpm – 72 mph – 8% slip
24P Solas Scorpion-6000 rpm-71 mph-9% slip
26P Bravo 1 -5800 rpm-70 mph-12% slip
23P Hill Pleasure 5 blade- 68mph-6400 rpm-15% slip
24P Blaster – 6500 rpm-65 mph-23% slip

[engineermike]

I considered the hill 5 blade cleaver but couldn’t convince myself it would be as reliable long term as the merc props. Here are my results below. I also have fuel economy/slip curves through the rpm range for all of them.

77 mph, 22% slip with a 26" bravo1
88.0 mph, 15% slip with a 27" blaster (7/8" above pad)
91.0, 15% with a 28" promax (7/8)
93.5, 13% with 28" promax (1 5/8" above).
97.6, 8.5% with 28" max5 (1 5/8).
88.4, 11.5% with 26" Maximus, 1 5/8.
87.0, 9.5% with a 25" P5X, 1 5/8.

[triplenet]

What lower unit?

Thanks guys - checking out all your posts now - really appreciate the info ....

BTW - Its the Torque Master lower.....

[engineermike]

For the torque master, much of the posted info wouldn’t apply. At 70+/- and the 4.88” case (?) the engine height and prop blade area isn’t as critical.

[mjw930]

For the torque master, much of the posted info wouldn’t apply. At 70+/- and the 4.88” case (?) the engine height and prop blade area isn’t as critical.

Is there a new TM case or was the SM and HD 5.44" the only cases brought over from the 400R?