Best way to increase midrange ?
 

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.

Re: Best way to increase midrange ?
 

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

Re: Best way to increase midrange ?
 

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.

Re: Best way to increase midrange ?
 

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

Re: Best way to increase midrange ?
 

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!

Re: Best way to increase midrange ?
 

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 ?

Re: Best way to increase midrange ?
 

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 :evilb:

Re: Best way to increase midrange ?
 

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

Re: Best way to increase midrange ?
 

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.

Re: Best way to increase midrange ?
 

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.

Re: Best way to increase midrange ?
 

based on whats happening would a smaller 3 blade cleaver in either pitch or diameter increase midrange acceleration ?

Re: Best way to increase midrange ?
 

i'm currently running 3 blade 15x32 labbed cleavers.

Re: Best way to increase midrange ?
 

Yes, decreasing the diameter would help the acceleration. It would not help the cruise speed though.

Re: Best way to increase midrange ?
 

well whats the next suggestion from here. how about a smaller 4 bl bravo 1...main goal is acceleration, and reliability as far as engines are concerned. was told a 4 blade would take some stress off the lowers. my current props are fine in every area but mid range acceleration. unless i'm low on fuel, light on passengers, and trimmed a bit.

Re: Best way to increase midrange ?
 

Julie or Matt...you mentioned a Hydro Quad VI. Do you have any test props in the diameter your thinking and that are already drilled ?

Re: Best way to increase midrange ?
 

i will measure my x dimension tomorrow

Re: Best way to increase midrange ?
 

:rolleyes:

Re: Best way to increase midrange ?
 

any suggestions ?

Re: Best way to increase midrange ?
 

As I posted on s+f you are welcome to try the set of 29'' 4 blade hydros I have. New Jersey is not far from MD. let me know if I can help
Michael 410-885-2848 We can even drill the hubs if need be

Re: Best way to increase midrange ?
 

i appreciate that, and after the Atlantic City Poker Run this weekend i may just take you up on that. going to also try reversing the rotation with the 28 bravo 1's and see how that affects it. but thanks alot for the offer. i appreciate it.

Re: Best way to increase midrange ?
 

Bern I am insterested in your results. My props rotate "out". When I changed to rotate "in" the bow lift was incredible, just a short touch on the button and I had way more lift then I wanted, of course our hulls are different and the Motion has a very wide tunnel (45''). I noticed no difference when docking but my top speed dropped 4-5mph in back to back test. The skaters seem to favor turning the props in. Post your results

Re: Best way to increase midrange ?
 

Bern I ran those 29'' hydros 4 blades on my motion saturday. Real simple.. they are not the props for my boat, struggled to plane, expected that (thru hub) not much mid range and I could not pull them over 5000rpm about 76mph. I went home and pulled the spark plugs as I though maybe I hurt a motor. Installed the 34'' 3blade cleavers and ran 104mph in the heat. Hard to understand how they could run almost 30mph slower then the cleavers!