Tail_Gunner
Admiral
- Joined
- Jan 13, 2006
- Messages
- 6,237
Not to much experience here with this type of setup, 78 Glastron GT 150 675lbs dry weight add 400lbs total load 1000 lbs.
1977 Johnson 70hp 2 stroke 120 lbs compression on all three cylinders runs very strong. Turns a older 3 blade right to 6000.
I believe it a 2.25 drive ratio.
So I use turning points prop calc and it comes up with a 21, using a prop slip calc that gets 48mph@9% slip. That seems just a smidge high to me for some unknown reason. Any input here or experience would be appreciated
I will be using a 4blade aluminium probably Solas top end is of no value to me.
1977 Johnson 70hp 2 stroke 120 lbs compression on all three cylinders runs very strong. Turns a older 3 blade right to 6000.
I believe it a 2.25 drive ratio.
So I use turning points prop calc and it comes up with a 21, using a prop slip calc that gets 48mph@9% slip. That seems just a smidge high to me for some unknown reason. Any input here or experience would be appreciated
I will be using a 4blade aluminium probably Solas top end is of no value to me.