Thought you guys might be interested in some of my prop testing results.
Been playing w/Bravo 1's on my twin O/B 24' Sonic antique. Kept hearing how great they were and had to try them.
A bit of background on my project:
Had an identical rig for 7yrs and tested anything/everything along the way. The boat ran the best w/a set of 26" OMC Rakers (very similar to Merc Mirages) @ 6400 @ 77/78 and ran the fastest w/a set of Merc Choppers of the same size @ the same R's but got to 80 MPH's. Slipped out of the hole and didn't carry weight as well though. Was also through hub exhaust on the Rakers and over w/the Choppers.
This rig is just getting through the teething pains of a full restoration and two motors built from who knows what so no WFO #'s yet.
Here's the interesting part though.
Started w/a set of 26" Bravo 1's and the thing was a pig coming on plane. Think 25' Checkmate I/O w/too much wheel on a worn out 454/330 on a full load of fuel.
Old Sonic was a rocket w/same pitch but one less blade.
So I wrote off initial results to too much wheel and traded my 26's to a member on the board for a pair of 24's expecting great things. 24's not as clean as 26's but not enough difference to see this.
Expected my drag boat back. Was shocked to see little if any improvement even though I dropped 2" of pitch. WTF?
A light bulb went off one night, woke me up and out to the shop I went.
NO EXHAUST VENT HOLES. Doh
My 26" Rakers had them and that told me all I needed to know. (I hoped)
Went to my buddies shop and poked holes in them and headed to the ramp.
Bingo

Again, no WFO #'s yet but I am sure I could now pull up two adults on slalom skis from a deep water start. Huge improvement.

Another interesting note to you V bottom guys. This boat has 4" more set back than old boat but still will not carry the bow w/the Bravo's and try's to hop. Doesn't do that w/my Rakers (a ton of rake) and doubt these wheels will ever work.
I'm shocked at that result though w/the additional 4" of set back.
Guess they're way better at lifting the transom than carrying the bow.

What you've done is the equivalent of slipping the clutch (or the tires) to let the motors get up into a rev range where they make more power upon takeoff. That's what ventilation holes do for a prop.

What you're also discovering is that the basic prop design hasn't changed - and isn't right for your boat. I'm betting that a set of props with more bow lift will make all the difference in the world. Time for a call to Brett at Bblades.

Absolutely understand that part. Just didn't check it and the first time I ever did a back to back test (or ever seen/heard of it being done) with and w/o the holes.
I doubt I'll spend the money on getting the Bravo's beat on to see if they improve or not. Have a set of 26 Rakers on the wall that already work excellent and are paid for. Was just very surprised to see this after everything I'd read about the Bravo's.
Takes a bunch of up trim to carry the bow w/them and zero w/the Rakers.

Curious are your props turning into center or out? Have read plenty of posts on larger sonics turning out with a problem with the hops...turning in seemed to solve a lot of issues

Doesn't do it w/other props though. I turned them the same way on the old boat and it ran awesome w/everything I ran but never tried Bravo's on that boat.
Interestingly, on that boat I did try reverse rotation. Changed nothing but that it and it ran horrible. Went from set up perfect turning out to in w/no changes. Starboard (now LH) motor then spun bad and never bit good enough to carry the bow.

Main thing I was trying to show w/this thread was the drastic improvement to planing time w/the addition of the relief holes.

if you want to carry the bow more and the stern less get some of the diffuser ring cut off, the lip on the diffuser helps to lift the stern. Don't take off to much at once (1/4" to 3/8" to start) will also let the prop spin up easier getting on plane. If you take off to much the props will blow out and you won't be able to get on plane. I think your boat is relatively light so should be ok but you never know. You can use a lathe to cut a ring off can always be welded back on later.

Never thought of that and I love to experiment, especially w/props.
I've taken a hammer/grinder to several props just to see if I was going in the right direction.
Best was a freshly rigged boat that would run 60 w/the stock aluminum prop but slip as soon as you hit the up trim button.
When I got done it ran 67 and would take full up trim w/o slipping.
Painted that prop pink just to screw w/people. Won a lot of lake races w/it
Beat by a boat w/a pink, aluminum prop.
And, Thanks!

Was bored today. Took off a 1/2".
Didn't have time to test though.

Hi! I took off 30 mm of my Rev4 prop tube. These props have a longer tube than normal, but without flare. I gained 1,5 mph and got much better bowlift / less transom lift

Cheeers, Toffen

this is a i/o.. on a formula 336 tried a set of bravo one 4 blades turning out,,the boat hopped and proposed like crazy standing the boat up to 70*,,i thought we were going over...we switched to props to turning them in and all the porposing went away.

juat my expierance with the bravo one prop..