Bravo III hi performance prop

[jumpjets]

I have a RINKER 262 CAPTIVA Cuddy with a 6.2L 320HP Merc and a bravo III 2.2 drive. It currently has a Merc bravo III factory 24P 3 blade counterrotating prop set on it, and the prop is way to small. The boat slams up on plane quickly, but it's top speed is low, and it's at 5700rpm WOT. It's supposed to be 4800-5200rpm WOT. The boat's minimum planning speed is at 3000rpm as well, which seems high. Right now the boat feels like an old chevy truck with 4.56 gears in it.

I'm going to upgrade to a 26p prop set, as that will get my WOT RPM into limits. I'm curious is anyone has any experience with some of the bravo III props available. Lower cruising RPM and top speed are important to me.

1. SOLAS 3 blade. Cheapest I've found, and available right here on iboats.
2. Mercury bravo III XR. Most expensive I've found, but I believe this prop is built for top speed.
3. Quicksilver Thunderbolt DPS. Marginally cheaper than the XR. I don't know much about it.
4. Hill Marine Four by 4. Great reviews, but it's a small company, and it's a counter-rotating 4 blade. That seems like it would have a ton of drag and sacrifice top speed.

Any recommendations?

 

[QBhoy]

Hi
youre right in changing the props for sure, but from my experience with similar set up on friends boats (both have the 350 mpi and bravo) the standard stainless counter rotating props seem quite performer orientated in general. They both have a maxum 2400sc with 350 mag mpi. These will both achieve 50 mph gps at around 5000 rpm and will cruise at 2700 rpm most efficiently according to the smart craft. Will only just stay on the plane at about 2500 and trimmed in

 

[Scott Danforth]

I would look at your tach. Unless your motor has another motor spinning it, it cant spin to 5700 RPM on its own.... The rev limeter would have hit and the fueling tables dont go that high

 

[QBhoy]

A fine point there.

 

[alldodge]

Agree check your tach an also what is you GPS speed?

Did a quick search and unable to find the clear weight for the cuddy but the open bow is 5800 dry, and has a 85 gallon gas tank. The 262 is also 28 ft 2 inches long. Your 6.2 does have 320 HP but does not have the torque needed to have it run fast.

Found some numbers on the 350 but not the 320 HP. The 350 hp motor has 350 ft lb torque starting around 2000 rpm and increases to 425 at 4600 rpm. The 6.2 needs rpm to build torque. Yours being a new 6.2, is also a 377 cubic inch motor and the 350 HP is a reman 383 cubic inch. Your setup is helped with the 2.2 ratio by increase torque to get it out of the water.

My rinker weight is 4800 with a 300 HP 7.4 and bravo 1 drive. This combo comes up fast and maxes at 60 mph at 4800 rpm. The 7.4 330 hp 450 ft lb at 2000 rpm thru 3500 rpm and then starts dropping off until max rpm.

I have tried several props on my Formula B3 and even did try the Hill Marine 4x4 24 pitch. The Hill guys are great and there props are to, but as you say more blades adds more drag. If you decide to try Hill, they will exchange props with you until you get a set you like, it just cost return shipping. Best to go direct to Hill and not use one of the other guys selling for them, they change a restock fee.

Don't think the 4x4 is the way to go for you.

 

[jumpjets]

I would look at your tach. Unless your motor has another motor spinning it, it cant spin to 5700 RPM on its own.... The rev limeter would have hit and the fueling tables dont go that high

You are the winner!!!

I hooked up an external tachometer (digital timing light) and did some testing. My tachometer is about 10% high. At WOT, the actual motor RPM was 5190-5200. I have multiple days of testing showing the boat tops out at 47mph in all conditions, weights, loads, sea conditions, etc....

Some questions:
1. I believe the rev limiter is limiting my top speed since it always tops out at the same speed, no matter the conditions. Any reason to think this isn't true?

2. If I got a 25p or 26p prop, I think I'd get some more speed without over-lugging the engine. Thoughts?

3. I have a Faria tach with the engine total hours counter in it. Can I buy a replacement tach with the hours pre-set, so my hours gauge remains accurate? Can I just get my current tach recalibrated?

 

[jumpjets]

Agree check your tach an also what is you GPS speed?

Did a quick search and unable to find the clear weight for the cuddy but the open bow is 5800 dry, and has a 85 gallon gas tank. The 262 is also 28 ft 2 inches long. Your 6.2 does have 320 HP but does not have the torque needed to have it run fast.

Found some numbers on the 350 but not the 320 HP. The 350 hp motor has 350 ft lb torque starting around 2000 rpm and increases to 425 at 4600 rpm. The 6.2 needs rpm to build torque. Yours being a new 6.2, is also a 377 cubic inch motor and the 350 HP is a reman 383 cubic inch. Your setup is helped with the 2.2 ratio by increase torque to get it out of the water.

My rinker weight is 4800 with a 300 HP 7.4 and bravo 1 drive. This combo comes up fast and maxes at 60 mph at 4800 rpm. The 7.4 330 hp 450 ft lb at 2000 rpm thru 3500 rpm and then starts dropping off until max rpm.

I have tried several props on my Formula B3 and even did try the Hill Marine 4x4 24 pitch. The Hill guys are great and there props are to, but as you say more blades adds more drag. If you decide to try Hill, they will exchange props with you until you get a set you like, it just cost return shipping. Best to go direct to Hill and not use one of the other guys selling for them, they change a restock fee.

Don't think the 4x4 is the way to go for you.

Thanks for the gouge. I'm really leaning toward the Mercury Racing Bravo III XR. It's expensive, but I wanna go fast.

 

[Scott Danforth]

You are the winner!!!

I hooked up an external tachometer (digital timing light) and did some testing. My tachometer is about 10% high. At WOT, the actual motor RPM was 5190-5200. I have multiple days of testing showing the boat tops out at 47mph in all conditions, weights, loads, sea conditions, etc....

Some questions:
1. I believe the rev limiter is limiting my top speed since it always tops out at the same speed, no matter the conditions. Any reason to think this isn't true?

2. If I got a 25p or 26p prop, I think I'd get some more speed without over-lugging the engine. Thoughts?

3. I have a Faria tach with the engine total hours counter in it. Can I buy a replacement tach with the hours pre-set, so my hours gauge remains accurate? Can I just get my current tach recalibrated?

1. That what rev limiters do

2. Try it

3. No, you would start over at 0 hours with a new tach. However have you verified the tach is mot st on 6 cylinders. You can also get your tach repaired

 

[QBhoy]

Hi
get yourself a vessel view mobile kit. Tells you exact rpm and engine data. Let’s you get the prop dialled in exactly. Also tells you precise data about fuel use amongst other things. Very cheap too.

 

[WesNewell]

More than likely your tach is just set in the wrong position. Set it to the right one would be all that is needed.
http://faria-instruments.com/site_manuals/IS0100_Tachometers.pdf