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hdean

Member
I have a 2003 2509 Trophy Pro w/hard top and am going to re-power from twin Honda BF130's to twin BF150's. I'm currently running Solas S.S. 4 blade 13 1/2 x 13's on the 130's. Aluminum 3 blade 13 1/2 x 15's gives me about the same peformance as the 4 blades. However a pair of S.S. 3 blade Honda Turbo props 13 1/4 x 15 gives me more speed at a lesser RPM, but is slow (doggie) out of the hole. I do need hole shot for a heavy load configurations when going to fish camp. Any idea what S.S. 3 or 4 blade props I'd need to give me good hole shot, and a cruise speed of around 26 knots @ 4600 RPM with a WOT in the 5500 range running the 150's? I'm hopeing to use about 7 GPH each at cruise.
 
Hello,

The important thing to acheive is 6000 rpm at full throttle with the boat loaded up with fuel and any gear you would normally carry. Putting too big a prop which drops the revs below 5500 at full throttle just causes the motor to labour and wont give the performance you are looking for. There is no formula for this just trial and error. Based on the fact you were using 13" on the 130's then I would expect the 15" to be a better selection for the 150's especially as they have much greater low down torque (BLAST)
Good luck and try the props you already have.

Cheers
John
 
If you are having a dealer rig the 150's, part of the predelivery and rigging is to make sure that the correct props are on the motor. It is their responsibility to water test it as needed to make it perform to the rated rpms.

You can check some actual tests of various boats on the Honda web site. You can determine which might be the closest to yours. Some may be smaller boats, some may be larger. It will help you get in the ballpark to start.

http://marine.honda.com/products/performance



Mike
 
Hello,

Important info....ensure brain is engaged before opening mouth....of course they are different sized gearcases....still think that the 15" will be close for your needs, but as Mike has said, it is the selling dealers responsibility to setup the boat correctly with the right props so you get the correct revs.
Good luck and enjoy the new Hondas
 
One other question, I use the boat at sea level and also 3000+ feet above. At sea level I'm heavly loaded going to fish camp, at 3000+ feet fairly light. Should I get the WOT up to 6000 RPM's in the loaded configuration at sea level, and expect a bit more RPM's at higher elevations (less weight) when I'm light? I know even with EFI, there is a WOT difference of (?) at 3000+ ft when loaded the same? Will being light and at elevation, off set the differance of weight at sea level and still have a WOT of 6000 at elevation? I know I'm trying to split hairs, I'm just looking for a pair of props that find some middle ground (water). Having props for the different configuration and a back up pair gets pretty spendy (8 props)!!!!!

Thanks for all the help.
 
I would prop it for the sea level configuration. Hopefully, it is also where you boat the most.

Not sure about how she will operate at 3000 ft. Most likely it will have somewhat less power since there is less air (although not a huge amount less). The motor will compensate with less fuel to keep the ratio close to the same. Thus, less power.

Mike
 
Mike,

So setting up and being light at 3000ft, I should prop to get a WOT all the way up to 6000RPM's. With the same props at sea level, and light, I would probably exceed a WOT of 6000RPM. But by adding the weight at sea level, I'd be back down in the mid WOT 5k RPM range?? AS I mentioned, I'm trying to find a happy median with the 2 different configurations and at different elevations. I did some rough calculations, the weight differance I'm talking about is about 1600#'s. (9600# heavy, 8000# light) So you can see what works good in one configuration is way off in the other, that's why I need to get as close as possable.. I called a couple different prop suppliers, and the dealer is still doing his calculating. One prop shop said S.S. 15 1/4 x 15 3 blade's. The other said S.S. 15 1/4 x 15 4 blade's??? BIG differance in those props!! I guess I'll go with what's suggested the most. I hope I can be close on the sea trials...
 
I would prop it for the sea level heavy configuration. You do not want it to boog down if not propped correctly.

When you are using it at 3000 ft ,if the power is not reduced much by the altitude, just keep the motor under 6000 rpm.

Mike
 
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