Offshoreonly.com

Offshoreonly.com (https://www.offshoreonly.com/forums/)
-   Formula (https://www.offshoreonly.com/forums/formula-36/)
-   -   Prop Help (https://www.offshoreonly.com/forums/formula/271854-prop-help.html)

A.O. Razor 03-05-2012 12:07 PM

I always liked the lines of that boat. Sweet project.

BTW, yes, by bottom condition I did refer to paint, nics, hook ect.

Rossman40 03-06-2012 09:46 AM

AO Razor, Ive been told to test a 19 &21 mirage plus. Just curious why you say a 21 will not work.

Matt

A.O. Razor 03-06-2012 11:38 AM


Originally Posted by Rossman40 (Post 3634459)
AO Razor, Ive been told to test a 19 &21 mirage plus. Just curious why you say a 21 will not work.

Matt

Matt.

Because you would have to run 58-60+ mph for that to work. Was that Brett @ Bblades who suggested the 21"??? Not to be down on your boat, but you'd need a 454/385 minimum to even begin seeing those numbers on a regular basis.

Here's some figures with your drive ratio and rpm rating with a 21" prop.

At 5000+/- rpms which is at the top of your rpm range.

10% slip = 61 mph, 12% slip = 60 mph, 14% slip = 59 mph and 16% slip = 58 mph.

And at 4800+/- rpms, which is at the bottom of your rpm range.

10% slip = 58 mph, 12% slip = 57 mph, 14 % slip = 56 mph and 16 % = 55 mph.

Deffinetly start with the 19". If you look in one of the previous posts, there is one with a 454 and 350 hp running 56 as best number.Therefore I'd say he runs 54+ on average with the B1 4 blade. Yes the BBC weighs more than your SBC, but the heavy Formula likes the torque of the BBC.

Anders

oh6662b 03-06-2012 12:02 PM

Rossman that looks great, hope to see it at the islands

Rossman40 03-09-2012 05:12 PM

oh6662b....you will see me.....every weekend over ther...lol

A.O. Razor 03-10-2012 01:58 PM


Originally Posted by Rossman40 (Post 3637526)
oh6662b....you will see me.....every weekend over ther...lol

Hi Rossman

How is the testing coming along?

Rossman40 03-10-2012 02:29 PM

Wish I had something to report, not testing till next month. My cabin is being gutted and redone at this time. I will keep you informed....its a wee bit chilly on ol lake erie


All times are GMT -5. The time now is 11:52 PM.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.