Having problems finding exactly the right prop

[Dhadley]

Re: Having problems finding exactly the right prop

I'll stick with what we've been e-mailing about. Since you haven’t tried any 4 blades stick to the 3's. Otherwise your testing won’t equate.<br /><br />The 22 4 blade I mentioned is made specifically for stern drives (typically low X dimension -- prop running deep) but it’s a totally different blade design than what you’ve tried. Therefore the ride and bite will be different. Without testing it's a total unknown on your boat.<br /><br />Let’s stick with the knowns that you have. We know the 23 Turbo has too much bite. The 21 Stiletto would have almost the same characteristics but with less bite. It won’t tolerate as much X dimension but with a sterndrive that’s not (easily) changeable anyway. <br /><br />The 23 Turbo was at 4000. The 21 Stiletto should put you right at 4300-4400. The holeshot should be improved. The venting can always be played with but may not need anything. If it goes to 4450 you can extend the cup and create lift and bite to bring the r’s back.

 

[stevens]

Re: Having problems finding exactly the right prop

Aw, shoot, now I was hoping to hear some really convincing argument why the 22P 4-blade would be perfect for me, as I have kind of warmed to the thought of one more blade.<br /><br />From your own testing, would you have a way of comparing the two props in question? (22P four-blade vs. 23P three-blade) Could you in any way venture a qualified guess as to how the RPMs will be relative to each other?<br /><br />I'm willing to trust your judgment on this one, I just need some reassurance that either prop is the right one.<br /><br />Edit: I guess my ideal would be 21P four-blade, but they don't make these. Would it perhaps be possible to repitch the 22P four-blade down one inch? How hard, how much and how good would it be?

 

[Dhadley]

Re: Having problems finding exactly the right prop

Its hard to compare this 4 blade to the 3 blade props youve tested. The only way to find out is test it. Without seeing the boat we dont know how deep the drive actuall is or how the hull will react with this prop. Our experience is that the 4 blade props GENERALLY have more stern lift and will run at a higher X dimension. <br /><br />I understand you want the best prop on the next purchase but without testing this 4 blade you will never know. It might be perfect, it may not. This is why we test so many props on all kinds of boats. The best thing, I think, is to go with the same props (blade design) youve been testing. You have the baseline. You know the 23 has too much bite but you like everything else about that design. The 21 is the next step to gain holeshot and rpm. If it were an outboard we'd go with the 23 and raise the motor. We cant do that with your sterndrive.

 

[stevens]

Re: Having problems finding exactly the right prop

OK - Thanks again for your help.<br /><br />I'll just do the inevitable; test both options, keep the one I like the most, and try to sell the other one. At this point, I have little to lose by experimenting some more. Eventually we'll find something that works out. I'll keep you all posted.<br /><br />Edit:<br />follow-up in this thread:<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=013294