Padraig

Again not a Scarab guy but the thing that gets me is that a 26 inch prop at 5000rpm doing 61 mph has 25.67% slip. Something seems wrong, IMO.

Padraig

Powerquest_Baby!!

Boats can gain alot of weight (especially if they have ever been underwater or ??) Have you weighed the boat? Do you KNOW for sure you have a 1.5 drive? Is your prop stock? So many variables but the slip is thru the roof. Im guessing your boat weighs alot more than you think but its just a guess

Brembofreak

Maybe the clutch in the Bravo Upper has some slide???
I have seen this before!

jens henrik

That is exactly my point. I have tried to different props 26 mirage plus and a four blade 25 Revolution, but with the same result. Instead of speed i just get a lot of foam behind the boat. feels like it sucks air down to the prop..

Padraig

How does run? Does it get on plane easily? Does it lighten up and carry the bow OK? What about trim, tabs and drives?

Does anyone know what other single engine Scarab 29s are running for props? It may be a heavy boat but low sixties seems too slow for that engine and the slip is way too high.

Padraig

jens henrik

The engine is brand new delivered with a dynochart. i can mail you the chart if you like to take a look, i can also mail you a picture of my drive if you are interested. It planes very easy, and my trim works just fine. I newer use my trimtabs. I know that the boat came from factory with a 26 mirage plus.

Tinkerer

How far below the hull is the prop centerline. I bet it is real LOW.
When you trim the drive do small adjustments make a big change.

hammerdown500

I have a 95 288 sunsation
My stock 502 ran 68 with 4 blade bravo 24. I had the ecms tuned, and exhaust swapped to emi. And was blowing it out. Swapped to a 4 blade bravo 26. And ran 70. Now running a built 489 efi and running and runs 68 but back to the 24. And the 489 is making 100+ more hp. Not sure what to say about thay

Padraig

How did the mirage plus perform?
How does the boat react when you trim the drive up? Does the hull loosen up as you trim up? Are you trimming up to where you start loosing speed and then dropping the trim a tad?

Please excuse the questions but I have no idea of your experience or skill.

Padraig

teclpse

A friend of mine who is an engine builder and very good with boats did the math on my boat and with a 20% prob slip in order to get 70+ mph gonna 525-550hp, could also be the out drive itself, my friend had his out drive rebuilt this year and picked up 5mph