Hope Glassdave is around to help . I'm replacing the engine stringers in my 20 ft formula and while engine is out I figure why not raise engine . my propshaft is currently 10 inches below bottom and want to raise it 4 inches so propshaft center line will be 6 inches below bottom . Any input ?

what year? i raised the X in my Scarab only two inches and its a whole different boat. Yea ten sounds kinda deep,

Dave ,

Let me start off by saying I do all my own design , glass work and paint and your the only guy I would take advice from .I thank you for lending a hand here all the time .

My Formula is a 1981 20 ft with 260 /alpha , it is my beater , super clean

Larry

Thanks Larry, thats a cool thing to say and i appreciate it. I actually enjoy this kinda stuff, I'm on here for social reasons and i absolutely love seeing the projects people get into and how far ambition and ingenuity will take a person. Heck i think buying project boats is what got me into the biz in the first place lol. If i can help keep a project under control with a little Q&A tech line well its my little way of giving back God knows i've got my share of help out of this place. Thanks man

On to the beater . . . . that Formula suffers from the same thing my Scarab suffered from. Back when it was new about all you could get in a prop was either a lop eared three blade or a cleaver an not much in between. I had Mirage 3 blades and went up two inches allowing me to spin a B1. Made it literally a whole different boat. I'm not sure exactly where yours should be but i would probably go up as high as i could barring and hatch issues.

How bout an Alpha SS drive? its -2"

SS would be nice but I don't want to spend any money as I'm tapped out with my skater . I can go up 4 inches max as the top of transom assy will be into swim platform and that will still have my propshaft 6 inches below which I feel is still plenty deep . Do you agree ?
As far as wood for engine stringer I was going to use don't laugh oak from a pallet glassed in of course
Where is propshaft in relation to bottom as of today on your scarab?
Larry

My X dim is at 17.75 which puts my prop shafts at about four inches below the running surface. Not sure how that translates from a single to a twin V though. I would think you'd be far better off at even six inches the your original ten. Pallet grade oak huh . well i tell ya what i am more of the mind it isnt so much what kinda wood as how it is put in and judging by all the stuff i have seen you do on the Kat I am sure you will take the time to cap it in right.

Thanks Dave . Today I threw the drive back on to take accurate measurement and here is what I have . The lower cavitation plate is even with the bottom which is pretty standard for 1981 thinking . That said my propshaft is 8.25 below and after further review I think I will raise it 3 inches so that the cav plate will be three inches above bottom and propshaft will be 5.25 below bottom . Do you think that will be OK ?

Larry

Yeah, from there i think it would be just a matter of prop tuning to find just what works. Kind of un charted territory for that hull i would think.

I feel 5.25 propshaft center below bottom is still fairly consertive. I plan on installing a 350 hp sb stroker down the road after my skater is done which may be never

Yep, conservative but very much in the ballpark of having a decent enough X dim to work with and take advantage of prop technology.


OK . . . enough posting for now for me, gotta get back to work