Knot 4 Me

Is the new 4-blade forward/3-blade aft lab finished prop-set for the new Bravo III XR drive designed to aid in lifting the bow or the stern? I have a porpoising problem with my current boat equipped with a Bravo III and a 26" prop-set and wonder what effect the new XR props would have on the boat. Thanks!

throttleup

My understanding is that they are producing new props and there will be a new 4B for the front propeller. They are also polish finished with the same prop shaft, the standard.

Julie

Knot 4 Me

Yup, I saw a set at the Miami show where the debuted the drive. I was told the drive and new props were designed for heavy performance cruisers that can have big HP like Formula's 400 SS. Julie, any guess on how these props would perform on a single engine, runabout style boat?

throttleup

Not without the specifics. I haven't seen the drive or the props. I am sure in a little time we will start seeing them out there. If you really want some good information I would call Mercury direct as they will have more experience than any of us.

Julie

Knot 4 Me

Will do. Thanks! By the way, do you do many Bravo III prop sets? If I keep the set I have, I'd like to get them thinned, balanced and polished and maybe have some cup added. Boat is a 2004 260 Chaparral SSi with the 496 MAG, Bravo III, 26" props, running 52 MPH GPS turning 4,800 RPM. I'd like to get a little more top end out of it if possible without sacrificing cruise efficiency.

throttleup

Yes, we do work B III props. Unfortunately cruise speed and top end are two different goals at two dfferent ends of the torque band of your motor. But we should work towards the happy medium.

Julie

boatman22

Does the new prop-set for the Bravo III XR fit older Bravo III's?

SeaRay Jim

I think I heard they would not, but that's not reliable info. I'd like to know the truth as well.

My Searay is heavy and if it'll help get better speed, or better anything without any sacrifice, I'm in, at the right price.

In the first season of having a new motor, I'm starting to see some "issues" with my virgin 30p's. I planned on having them labbed once I got a few hours and knew what she does and needs, but at about 45 hours, I have burns on each of the 3 blades on the rear prop. One blade is pretty bad, but I think will be eliminated with labbing. I'm just concerned about why I'm burning holes in this thick clunky rear prop.

Sorry to hi-jack, but below is a pic of the prop and then a close up of the same blade which is the one that's the worst.

Oh, and to show how bad out of true BIII props are, each burn is very different in shape and severity.

throttleup

Is there any cup in the trailing edge of the propeller? Thoses are indeed cavitation burns. You should really determine what is causing them, or I am afraid that the life expectancy of your props wil be drastically reduced.

Julie

SeaRay Jim

Julie,

There's no cup at all. They are box stock standard 30's. On another site, this subject came up because others, going from memory, all with stock smaller boats, but big blocks had the burns as well. However, at least 2 of them were labbed and polished (vs. satin finish) and the burn was more of a discoloration. Mine's obviously much more than a discoloration. Also, it seems to be an issue with higher pitched props, like 28's and up.

Could it be from just being way out of true and unbalanced (as most BIII's props are) and being under a heavier load at higher RPM's at a higher trim level? When I noticed it at the degree it is now, it was after a trip where I ran harder than normal and for longer than normal so I'm leaning towards this being from higher RPM's to WOT. This is a Searay 240 Sundeck (deck boat style) that weighs close to 6000# on the water running a 540cid so I don't have any reference points with an applicationn like this. It's kind of a sick and twisted application.