SFOcean

iTrader: (1)

I would be surprised if you can turn that prop much past 5000rpm. Let us know

wannabe

I was about to say 1.36 and 31 inches. You are going to be flying if you can break it loose. I hope you have good steering cause chine walk may be your big issue.

Wannabe

ridefast77

iTrader: (5)

Im doing just about the same set up on my 28 but im going to run a 1.50 in my drive. keep us posted i can't wait to hear what your #s are! good luck.

FORMULAfast

Well been out testing since wed and I think the prop is to much not sure if it's the dia thats killing it or the pitch but it wont run much over 4,500 rpm unless I trim it way up and then it starts to porpoise really bad can only get 70 mph out of it any ideas here?

the old prop I had on the #3 was a 26 pith 4 blade hos 16 1/2 inch dia best speed out of that was 85 mph but chined really bad hence the idea of going to a shorter drive!! [ATTACH=CONFIG]506452[/ATTACH][ATTACH=CONFIG]506453[/ATTACH]

FORMULAfast

[ATTACH=CONFIG]506454[/ATTACH] heres the setup now

SFOcean

iTrader: (1)

Your old prop had a LOT less stern lift. From the round ear, you now have a cleaver with another blade, 1 1/2" more diameter with probably less rake on a shorter x-dimension drive; all adds up to much less bow lift, or more properly, more stern lift. Does your hull have steps? If not, I would guess your better off with a prop like your old one. The pitch doesn't help you either, your engine is not in its power band, probably down 150-200HP (or more) at that RPM. When you trim it way up, the center of balance and center of pressure are not near each other, hence the porpoise. So, I would guess a round ear (clipped cleaver) 3 or 4 blade 16" in dia. mid 20s pitch. You really should contact BBlades Propellers. www.bblades.com talk to Brett.

FORMULAfast

Hey thanks for the impute... I don't have a notched transom or steps in my hull ! What your saying makes sense because when the boat is up on plane it feels really flat ! I figured with the #5 drive and having 1 1/2 prop shaft center line dimension it would need a lot of transom lift I guess I thought wrong. Not sure I will be able to find a clipped cleaver but I will call bblades mon Thanks Again

cougarman

[ATTACH=CONFIG]506685[/ATTACH][ATTACH=CONFIG]506686[/ATTACH][ATTACH=CONFIG]506687[/ATTACH][ATTACH=CONFIG]506688[/ATTACH][ATTACH=CONFIG]506689[/ATTACH][ATTACH=CONFIG]506690[/ATTACH]



When Bill Started Development on the Checkmate Nobody including Mercury knew where to start.
This was new territory,......keep in mind this is about 15 years back now.

But the project started out with the drive very high,.......and by the end it was lowered almost
like 10"'s or 12"'s. I could check with Bill but it's basically running the same depth you would
run a bravo 1 Drive at.

Not sure why, but the singles still like a little depth to get the boat free'd up to run at speed.
Prior to this the but just would run like she runs now.......Freight Train on RAILS.

There were a few other big engine # 6 boats on OSO ( SlimShady 32' Activator ) that found out the same thing
to get there boats to run right.

So Not sure if this principal apply's for the #3 and #5 drives,.........but keep it in mind
you may end up putting the drive lower than you think for a Big Engine Single

Thanks
Jon

TJIndy280

Hey Formulafast,

Bill and I are joining the group up in your area this weekend (thread in Great Lakes), come out and join us. Bill loves talking about what they have done with this Checkmate over the years, it is truly awesome! They have gone through a lot of trials to get where they are now. We will be getting into Traverse City Thursday night. Would love to have you join us.

cougarman

Couple of these. TT 1,500's would look good in your OL



Jon