props turning in VS turning out...
 

Can someone explain the characteristics of prop rotation?
I have a 93 Cig TG, flat bottom. I have the props turning out.
What changes exactly by swapping the props? I assume a bravo XZ drive doesnt care which way it turns? how does that work? If I swap props is that it or do I have to change any cabling? Also, What do you gain or lose by props turning in? I have heard you gain a little top end with them turning in but is not as maneuverable around the docks? Is there any difference in planing, handling, props aerating, etc? Any additional info I can get on this would be helpful. Thanks.

If you read Powerboat Magazine, Bob Teague answers this question in his tech section in the latest edition.

Even if you search all of the threads on the topic, you'll find no consensus on the subject. Some say spinning inward provides bow lift and some say stern lift. So, just give it a try by switching props and running the shifters in reverse. If you like it, then you'll need to move the shifter cables.

I tried it on my Sonic 31SS only to observe absolutely no difference in top speed whatsoever. I didn't experience any of the negative side effects, either. It still handled fine at the dock. Since there was no benefit, I left my props spinning outward. My boat doesn't have steps. I believe a stepped hull would be impacted more.

Spinning in creates more bow lift.

You can just test it by running the shifters in reverse. To permanently change it, you need to reverse the cable connections on the shifters.

so it should help the top end then, right?

I think it all depends on power ,X dimention and hull design.

But yes ,,,they say it helps top end.

My PP i had, actually was faster turning out.

LOL, I like the refence to BT. I remember Dennis C. and them me explaining that to him (Dennis of course taught me).

Inward rotation creates bow lift. Outward rotation creates stern lift.

With inward rotation the stern leverage is more defined just post the 6 oclock downward motion as the propellers rotate upward causing more transom leverage and creating bow lift. In reverse, the thrust from the props is directed against the transom, adversley affecting rearward momentum.

Check for this in the next ask BT section...LOL

Brett

Sorry, I couldn't help myself.

Each application is different but the physics stay the same. If you have questions specific, let me know and I'll do my best to help you figure it out. There is give and take in each and every set up. All identical set ups are different.

B