SG 21

John Seybold · Oct 4, 2024

Hi,

I finally had time to give an old SG 21 and new life. The hull need some cleaning up and refinishing. I’m looking forward to doing some testing. Thing k I’ll start with a 1440 with the pipe at 8 3/8 to 8 1/2’. Hope to end up with a 1445 at 8’ burning 40%.

Chris Wood · Oct 4, 2024

I remember racing that style boat. had to run alot of strut angle 1.5 degree's negative and keep the front end light. boat does not like alot of front sponson down force.

John Seybold · Oct 4, 2024

Thanks Chris, right now I have everything at zero degrees, ie sponsons and strut. I’ll see how it goes from there and make adjustments.

Roxyflash · Oct 4, 2024

Reminds me of my daughters sg

shoboat · Oct 5, 2024

John,

1445’s or H-4’s work very well on that old girl.
Just keep the trailing edge cup under 3.46”
Had one for awhile when they first came on the
market from CMDi. Nice vintage piece. Forget
the 1440’s that is not enough propeller for that
engine. I would try some different pipes as well.

Thanks For Sharing,

Mark

John Seybold · Oct 5, 2024

Thanks Mark and Chris,

Chris wouldn’t negative in the strut push the rear end up and the sponsons down?

Roxyflash · Oct 5, 2024

We ran a h7 on cool days and 1445 on hot days

Chris Wood · Oct 5, 2024

John Seybold said:
Thanks Mark and Chris,

Chris wouldn’t negative in the strut push the rear end up and the sponsons down?

yes sir. more negative also helps on launch and will plant the front end in the corners. just watch you get to much you will have prop chatter both coming out of the corner and in the s.a.w. ( also helps pull bigger props )

my boat like more strut angle and less front sponson downforce.

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