29 scarab prop slipage

shotime113 · 09-08-2007, 08:52 PM

Can someone tell me if they are having a lot of prop slipage . And what do you do to get the slipage to a minimum. 750 hp with a 30 pitch mercury prop. WHAT CAN i DO ?

fast22 · 09-09-2007, 04:22 PM

What kind of #'s are you seeing? Speed,RPM?

shotime113 · 09-09-2007, 08:21 PM

At 4000 rpms the boat runs 53 mph on gps. with heavy people in the boat at the same rpm it will run just a little faster at 57 with all out blow out.

fast22 · 09-09-2007, 08:53 PM

I've got a 509" with a whipple running low boost like 4.5lbs at 5300rpm. It makes about 650hp at 5300rpm. I have a stellings extension box and a stantard length bravo with a nosecone. At 4000 I'm runnig about 49-51 depending on the load. I'm not sure about topend yet, Ive been having some trouble with my outdrive and it crapped out on me this weekend but best so far is 72 with a lightload. Ive heard alot of good things about the 2"shorty on these hulls, thats the next step. But I don't have much of a problem with blowout at all.

shotime113 · 09-09-2007, 11:47 PM

Are you running a bravo 1 or a XR drive? I have a bravo 1 And have been toldby teague to put a 1 inch spacer on the drive.. so I will be trying that.

fast22 · 09-10-2007, 07:43 AM

Its a regular Bravo One. Maybe the box is helping me but I have very little blowout if any. I'm running a slightly worked bravo one 26p. Maybe the extra HP you are making in the differance, have you tried a 5 blade maxximus yet? I'll be ordering a xr upper and a imco 2" shorty in a couple of days and start testing set up. I know the X-dimension on our boats is not the best.

shotime113 · 09-10-2007, 11:10 PM

Ok what size box are you running . But I seem to think that the drive is not deep enough under the keel . There also is a lot of white water behind the boat after I get on plane. Its like a serface drive. AND THANK FOR HELPING

fast22 · 09-11-2007, 07:46 AM

Its a 12", set at neutral hight. When I bought the boat the box was already on there, so I'm not sure how it performed without it. If you have that much whitewater your deffinatly pulling too much air, have you though about a nose cone? It will cut down on the turbulance coming off the hull going to the prop.

custom29scarab · 09-11-2007, 02:45 PM

I am running a standard bravo 1 with a 26 bravo 1 I am runnning a solid 72 at 5050 with about 625hp. I have seen 74 a few times and I cruise at about 4000 at about 50-52. I also have 509 with a B&M 250 making 5 lbs at 5000rpm. I do have some cavitation at some trim and cruise and have to adjust the trim and it goes away. I would like to spin my motor up to 5400rpm but haven't had a chance to try any other props yet.

custom29scarab · 09-11-2007, 02:49 PM

Shot,
as far as your question goes contact Julie at Throttle Up. She is a member here. She is very knowledgeable and will be able to help you out. I