CaptainChinewalk

G’day all,

Have been testing various propellers in the hope of tuning my boat in a little better………
Boat is a 21’ shallow V with small pad, 2000 model 350 MAG MPI Bravo 1, imco -2” lower (prop shaft 6” below pad), aftermarket headers, thru transom 4” pipes, dual ram full hyd steering, weighing approx 3400 lbs with 2 POB.

With a 23”Pitch Laser II boat will run 37-38 MPH @ 3000, 69 @ 5000 with significant chinewalk above 64 MPH at neutral trim (prop spins faster but speed decreases when + trim)…..feels like it can’t carry the nose with the new lower……with original lower (+ 2”) carried it easily.

Mirage+ 25”, 42 MPH @ 3000, will rev to approx 4400 neutral trim, max up trim 69 MPH @ 4800-4900, slightly less chinewalk than laser II…..maybe…….prop felt very well hooked up to the water.

Bravo 1 24”, 41-42 MPH @ 3000, max 4500 RPM at neutral trim, max up trim slight porpoise approx 68 MPH 4900 ish…….seemed like almost no chinewalk…… prop felt less connected/hooked up to the water than the Mirage + although seems to go quite well.

I guess my question is what now……..Hydromotive 3 blade?, some sort of cleaver prop? none of the props have stood out as the one to choose, perhaps the Bravo 1 but as the boat easily gets on plane even with the Laser II I don’t think I need the extra blade.

Basically I’m trying to get the best possible top speed, I’d like to minimize chinewalk, and keep a strong midrange……and yes I know, I’d like to fall into the swimming pool at the playboy mansion as well BUT some things just aren’t on the cards!........Any suggestions or comments would be appreciated, all speeds are GPS…..

Many Thanks.

BY U BOY

try a 23p m+

bbladesprops

24 or 25 Tempest Plus.

CaptainChinewalk

Thanks for the replies,

I guess what I'm really looking for is some suggestions on which style prop and why........the boat seems to have quite good natural bow lift and comes on plane easily, am I wasting potential speed by running a large bow lifting prop designed for heavy boats (Mirage+)? is my prop shaft still too deep to take advantage of these larger props?

BBlades.......why the tempest?, (from my position of complete ignorance) it looks very similar to the mirage+, large 3 blade, bow lifting?.........how should it differ?

Thanks again.

bbladesprops

Sorry for the delay.

This propeller is more suited to carry a boat of your size correctly. It has a completely different geometry to the M+.

It is a bass boat prop that can work quite good on your hull design. This prop will run on stern drives. It leverages the stern well and carries the bow. I think it will work well. If it doesn't we will learn from it.

We have test props available for a small $20 fee. No strings attached!

CaptainChinewalk

Brett,

Thankyou very much for your advice, good information is incredibly hard to find........I will try a tempest+ and get back to you with the results.

Can you give me any explanation as to why the Bravo 1 wouldn't cause the chinewalk that seems to be so prevalent with the others?......I'm guessing just more hull was left in the water?

I appreciate the offer of a demo prop BUT as I'm in Australia I guess it's a little far for me to travel ;-)........luckily I have a Mercury dealer that puts up with my requests to try props.......for the moment anyway!

Thanks again.

Mick

CaptainChinewalk

G'day Brett,

Finally managed to try the Tempest + 24 that you recommended in your previous post............top speed 12.9 MPH GPS ........basically couldn't get on plane...........I'm sure with a lot more perseverance I could have managed it BUT as the boat is used for skiing it just doesn't work for this application.

Any suggestions?

Thanks

CC

bbladesprops

OK, I think we need to go a differnt direction. I didn't know this was going to be a skiing applicaion. That doesn't matter with the planing issue. I'm surprised it didn't get on plane.

would like to see you try theRevolution 4 propeller in a 23. Since the 4 blade helped to control the chining before, the same should apply here. Also the 4th blade will help in your hole shot.

CaptainChinewalk

G'day Brett,

Many Thanks yet again for your help, the only thing I can think of which may have hampered my getting onplane with the Tempest+ was that I haven't installed the Cav Plate extension that is recomended after installing the Imco lower, as the boat comes out of the hole brilliantly even with the tiny LaserII I really didn't think it would do much.........does it really make that big a difference?

I did try the 23 Rev 4 prior to installing the 2" shorter lower & thru transom pipse and managed 41MPH @3000 and 65 @4650-4700 (with mild walk @ the normal speed of 64-65), so far the Bravo is the only prop that the boat hasn't walked with.......

Do you still think I should re-try the Rev 4?

Thanks

bbladesprops

Yes I would still try the Rev's.