Re: Tried new Hustler
With the first prop the reason the motor got to 6000 was beacuse of the over 21% slip. That could be because it was worn or from blade design. In any case the second prop was much more efficient (no matter why) and the slip was at 12%.
The second prop has more "bite" - again no matter why. We'll assume it is a little better design. Or maybe the first prop, when new, had more speed. It really doesn't matter.
In any case he gained 10% in slip and 2.5 mph. The new prop has enough bite that if the set up is tweaked, starting with X dimension, he may recove some or all of the 400 rpm. In any case whatever he gains will again decrease slip % and gain efficiency.
Lets assume he raises the motor slightly and the prop design and hull design responds favorably. Even if he stayed at 12% slip his speed (theroriticaly) would be at about 42+, almost 43. Any gain in slip % would net even more speed. Therefore it would be more efficient over the entire rpm range.
Thanks for the explanation Dhadley, that makes sense what your saying but I am still a little confused, hopefully he will chime back in and let us know what numbers he was running when his prop was in new condition?
That being said and reading his above post about motor height etc, could it be that his motor/boat combo is already set at it's optimum level now and that his factory prop was so ineffecient it allowed him to reach 6000rpm?
Most of the 115 motors that I have seen from the dealer for his type of boat come with 17P props, I am not sure why but the 90's seem to come with 19P props?
I know there is only one way to know for sure and that is raising the motor but to me it seems like a lot of work only to find out his motor is already in it's optimum position? I think the 17P is what he needs or how else could one possibly know what exactly the right prop was for any application?
Let me try to rephrase that? He stated he was able to reach 6000 rpm with his current prop, assuming I bought my boat with my Black Max and it gave me exactly 6000 rpms, had a great holeshot, very little cavitation etc, would I not think the motor was running mint and this was the perfect prop?
How would I know unless I started playing with motor height? Assuming this is the case then what your saying is any new boat with an outboard should always be raised/lowered just to make sure they are running the right prop?
I think that 17P would work perfect and by the sounds of his engine height, he is already there or very close to it's optimum engine height?
Assuming he raises his motor and with his current TP 19P prop he reaches 6000 rpm, perfect right? Then he dings this up and needs a replacement and chooses say a Michigan wheel the next time and he sees 6400rpm? Then he is back into lowering his motor again, no? My point being, how would one possibly know what "perfect is" if everything changes every time you throw a new prop on? That is why I am thinking the 17P he is thinking about purcahsing now would be perfect without having to fool around a bunch of times with engine height etc?
I hope that makes sense? I have a hard time putting what I am thinking into words!
Like stated above, not disputing you, just trying to learn is all. Thanks again............Irv964
