puder

i keep running the number through the slip calc and wind up around 25% slip. How can i redcue taht? i tried out a mirage 3 blade (not a plus) and could only get about 62-63 at 5400.

Would a 4 or more blade prop hookup more? Currently my drive won't trim up as high as it should (still figuring that one out). But even with the old engien/drive it always had high slip #s.

It does have a through hull fitting about 5'-6' from the transon. Older Scarabs are the only performance boats i've ever seen with these kind of through hull. Quite frankly they look like they belong on cruisers. Is it possible this is could be causing a wierd flow of water on the running surfaces? Like as in perhaps the water coming to the prop isn't so clean and full or air bubbles hence any props i've tried don't hook up so well??

PatriYacht

What boat do you have? Those mirages slip like crazy on larger boats. Switching to 4 blades will make a big difference.

ofshore

What percentage of slip should you have? I'm getting around 22-25% too (if trs drives have a 1.5 ratio). I also have through hull fittings if that could be causing the problem.

puder

1987 27' scarab bravo with 1.5 gears. i also have a nosecone on the drive.

Bob280Silencer

I get around 11% with my Bravo 1.Are you using a GPS speedo?Does the trim work enough to get the bow out of the water?Bob

puder

the bow seems a little low due to the trim issues we'll see late ron today.

th speed was on GPS. I didn;t reset teh trip settings so ididnt; get the ctuall max speed. My buddy was watching it though whie i was driving.

homan

I feel your pain my brother, know matter waht I do I can't gain any speed put on an Imco 2" shortie gained some rpm no speed this piece of crap doesn't care if I have 1 pass. with a 1/2 tank or 2 pass. with a full tank it won't go above 66 mph on gps that's not true I went up 1/10 mph my barge is an 88 28'` excel. It's weird I'll hit a certain speed maybe 55-60 and it almost feels like I hit something in the water but what I think is happening is the the boat is rising higher out of the water and then starts to nose dive. I'm wondering if an extension box would help to offset some more weight either that or have my fat sister sit on the swim platform but then I might not be able to plane off.

puder

ok fully trimmed she ran like 62-63. The slip #s are damn near 30% ????

ideas????

Jonas

gotta be the prop try some hydro's they love my non step fountain,

Mbam

Puder, try a Mercury Revolution, should be worth 2-3 MPH