1972 SeaCraft 20sf (re) build.

[Caymanboy]

20’ SeaCraft SF with bracket
Performance Data
6/16/13
Calm seas.
40 Gals fuel, one person, med load.
14 ¼ X 17” 3b Yamaha SDS Reliance Prop.

RPM GPH MPG Spd Knts.
1000 .7 8.3 5.
1500 1.3 6.8 8.
2000 2.2 4.8 9
2500 3.3 3.8 11
3000 4.3 4.7 18
3500 4.9 5.1 22
4000 7.2 4.3 27
4500 9 3.9 30
5000 13 3.1 35
5500 16.5 2.4 39
6000 19.5 2.5 44

I still need to do some playing with engine and prop. Want to get a little more speed out of her. :-)

[drtyTshrt]

As mentioned before. That 5k RPM slot looks good.
I bet you could go to a 19pitch and stay pretty close with your numbers.

[Caymanboy]

Originally Posted by drtyTshrt

As mentioned before. That 5k RPM slot looks good.
I bet you could go to a 19pitch and stay pretty close with your numbers.

I'm going to raise the engine up a notch.
Try a four blade.
And will try a 19".
I like what you are saying. ;-)

[hermco]

Nice clean job there young man.

[uncleboo]

I agree! Beautiful work!

[RUSTYNTABATHA]

the four blade should help lift the stern at lower speeds also !! maybe even try out a 5 blade.... ;-) get speed lift and load carrying..

[YeA 20sF]

Perfection.... Nuff said

[Caymanboy]

Originally Posted by Calibogue

Your lenco actuators mounted through the bracket!
I will need to do the same for them to fit and get the bracket height correct.
How much rise did you use per inch of setback?

For every 12" of setback, I raised the engine an 1", or should have.
I am happy with the bracket height, it is down low enough that I get a good portion of the flotation values, I can still mount lights, thru hulls, etc, thru the main hull and it is a good height for boarding.
But I feel the engine could go higher, so I will raise it a notch.
How is your project progressing?

I thank everyone for their kind comments.
It appears as if the wind Gods may have changed their minds, the first forecast for this w/e was ESE 15-20knts, little too sporty for my taste in this boat. Now that has been revised to 11-14knts, if that is the case, I'm ouuta here!!
Final touches going on, TUUCI Top, etc.
Last is the cooler, spear, rods, fins and TM/LLL II. :-)

[Calibogue]

By next Friday I will be ready to hang the engine!
Thanks for the info....I have been dreaming of bracket heights.

[flyingfrizzle]

Originally Posted by Calibogue

By next Friday I will be ready to hang the engine!
Thanks for the info....I have been dreaming of bracket heights.

From everything I have read and what I have been told this is a good starting point. Most everyone has had to raise their motor up from here and never down. So make sure you leave your adjustment so you can go higher from this point so that you can fine tune it in. I am also starting at this mark and setting the motor so all my adjustment holes will allow me to go up higher if needed.