berns29scarab

Currently running 15x32 cleaver's on a 30 spectre with 300x's. WOT approx 6400rpms at 105.5 on a garmin 182 c, with 2 people and 50% fuel. would like to increase mid range as much as possible without giving up to much up top. The props are spinning out if that makes any difference. most time spent in the 65-90 area anyway. cruising is approx 4500 rpms 70-73mph/ 17 gph per motor. Open to suggestions. All the above figures are with minimal trim...very minimal so the WOT figures could probably increase a bit.

throttleup

If you run your boat in the mid range most of the time the cleavers are not the best choice. There are other prop options that will improve the performance of the boat through-out the rpm range with the exception of top end. The cleavers are great at the top end and thats where they are really designed to run.

In applications like yours by using different props expect to see a loss of about 2 mph on the top end with a mid range speed increase of 4-7 mph. Getting on plane is much better as well. If you would have any questions give us a call.

Matt

bbladesprops

There are numerous options for propeller selections.

We have had great success using Bravo 1 propellers on 300X outboards. We have done this on Jay's boats before. His 30's like the outboards to spin out most often. The mid range performance improves drastically with minor acceptable losses at WOT.

There are also 4BL cleavers as another alternative.

berns29scarab

i spoke with Jay and he said he had never heard of running bravo 1's on outboards ?

bbladesprops

We have done this countless times on 3L OB boats (various configurations). Jay's included. Most of his customers do run Merc OB cleavers as the prop of choice, simply for the top end. On the old 300's we would always drill vent holes in the hub to compensate for the stiff pitch required to keep the rev's. in their required zone in order to help the hole shot. On the X's it isn't always necessary. I would suggest trying them without the vent holes to start. More than likely you will need them. If you get the chance to try them, do!

berns29scarab

i just tried a pair of bravo 1 non labbed 4 blade 28P's. Couldnt get her on plane, reguardless of trim,i had to go alllllllllllll the way out on the bow to the end between the sponsons and have my buddy start to trim her up until they broke thenshe planed. Had to trim it almost into trailer mode to stop the porposing, and to keep the sponsons from grabbing the water and hooking the boat. Once trimmed i got her to 67-6800 rpms but at only 98 mph...at 4500 rpms was reading 68.9 mph....WHATS NEXT ?

berns29scarab

i always thought that bravo 1's would give you bow lift and figured i would need little to no trim but this was absolutely not the case here..would a smaller diameter or smaller pitch cleaver help. I just dont want to use a $3000.00 pair of props as every day props...want to save them for the special occasions if ya know what i mean

berns29scarab

oh and reguardless of how i trimmed her i couldnt get more then like 25-2800 rpms out of her until i went up on the bow

bbladesprops

The vent holes would be a must from your description of the planing ability. Labbing would help too. If you still have the props, you could try reversing the rotation to see how it affects the boats attitude, but you would still need the vent holes installed. You're 4500 rpm speed some what surprises me. I expected better numders.

Any time you increase the number of blades or the diameter, you increase stern lift. Bravo 1's are only concidered bow lifting props as far as a 4BL prop are concerned. A true bow lifting propeller would be a 3BL chopper.

There are 4BL OB cleavers that you may concider. They will help a little in the cruise area but not on top end.

throttleup

Your cruise speed is better than you think. Keep in mind that you with your cleavers you only turn 6400@WOT. If you were to run 30 Bravo's that would put you at about 6400@WOT but your cruise speed would increase about 5-6 mph.
We have found that the Bravo 1 is not the best prop in your application for a cruise prop. A Hydro Quad IV (a semi-cleaver) with a slight diameter reduction will give you the best of both worlds. They don't have to be lab finished so you are looking at a prop that is a fraction of the cost of your cleavers. Lab finishing would decrease your cruise speed thus defeating the purpose of your goal.
Vent holes in your application are a must and will eliminate the problems you have getting on plane.
I am a little surprised about the difficulty keeping the bow up. This usually isn't a problem with your boat. The outboard cats are finicky boats. When you change props you may have to adjust the motor height as well.