F2 Leecraft Engine set-up ( engine height )

[MirageBoy69]

Hi , I need some help guys . I'm rigging a leecraft tunnel hull F2 with a 2.5 Merc , 12 inch mid and an adapter with a Cle gearcase ( lefty ) . It has a new transom soo I can put the engine where I want . I'm trying to figure it out where to start to put the engine height , prop shaft center line , even with the sponsons or below ???? above ??? I'm going to use a cleaver prop . I will apreciatte your help guys .... Thanks , Jose .

[MirageBoy69]

Any opinions /???? ?????
Thanks , Jose ..

[elite service]

I always mount the jackplate with the adjustment close to the middle, propshaft even with the bottom of the boat.Then you can adjust down or up when your water testing, or doing different types of running (top end,drag etc) that has always worked well for me.

[Mike Nass]

OK, here's what I can tell you and think... for what it’s worth… I have a F1 Seebold, 2.5 champ with a SSM gear case... it is set with the centerline of the propshaft exactly even with the bottom of the sponsons, I have 1 inch of upward adjustability, and this boat usually likes it about 1/4" up from the bottom for most conditions... a bit more up for calm, all the way down for rough... again, that is with a speedmaster and 10" prop... the sportmaster gearcase makes it all different, you have 4" bigger prop and much more gearcase size wise... I would think you might be be closed to 1.5 inches above the bottom, perhaps even higher... guys with 5 inches of setback on modvp hulls (i.e. STV) seem to like about 1.25" or just a tad more above, but that’s with a center sponson, closer to 7/8ths without setback... if it were me, I would go for about 1.25 - 1.5 above to start... that might sound high, but remember, you have 2 more inches of prop hanging down into the water and larger blade area as well and at speed there is very little drag and hence less blade area required, plus no sponson in the middle so the water will rise higher to the prop that would be the case on a mod vp hull with a center sponson... I would not be surprised to find the sweet spot closer to 2" above with a sportmaster and 14" or larger prop... I hope that made some sense?

BTW, what is the intended use of the hull? Why are you going with the sportmaster in the first place?

Cheers,

Mike

[kb5050]

not sure how well that combo is going to work, those boats are designed to have the speedmaster gearcase and small diameter (9" - 11") diameter props. the large diameter gearcase and prop are going to create alot more stern lift. I'd be very careful....Why the CLE? What is the intended use for the boat?

[MirageBoy69]

Thanks guys , Mike that make sense . Here in Puerto Rico is a class of Formula boats but there are sst 120 , soo 2.0 liter engines with SSM . I bought that boat without engine and have a 2.5 that was on another boat that is gone . The only rule that they made is can run the 2.5 but not with SSM , and then I would run with them . Thanks for all your help and opinion guys , other are welcome ...\
Jose
...

[MirageBoy69]

??????????/ any ideas ??
thanks , Jose ...

[kb5050]

Kinda in uncharted territory... normal procedure is to start with propshaft even with the bottom of the sponsons, start testing, see how it feels.... are you the first one to try the 2.5/CLE setup?

[patchesII]

I'd use an XR6 case before I'd use any other big case