Catamaran CG ?

[chipgibbs]

On a Catamaran hull with the now typical overhang, how do you measure the CG? measure only the hull in the water or the entire hull including over hang?

Thanks

Chip

[100 mph jet boat]

no overhang

like your cheetah would be 32in...... total boat is 34 1/8in

[SirBudman32]

If thats the case I need to change my Cheetah

[keithbradley]

Most use the splash chip, so measure from the sponson transom.

[chipgibbs]

Thanks guys, This would explain why I keep blowin over. looks like I'm about an inch shy of right.

Chip

[100 mph jet boat]

if i did it right :)

on a cheetah
hook a tape on the rear of the sponson riding surface and measure forward 9.6 in = 30% 10.24in = 32% 10.88in = 34%

[SirBudman32]

Thanks, I try that

[chipgibbs]

Well I trimmed the noodles and got the batteries to move forward a bit. Looks like I've got the CG at about 9' from the rear of the sponsons. Probably at about 28.5%.
I also originally built the boat using 4200mah batteries and now have 5000s. The longer battery can't be moved far enough forward w/o adding some more battery tray.

Hey...First build and I'm still tickled as s__t.

Chip

[chipgibbs]

Gave the Cheetah a few runs this morning. Tried some different props and strut adjustments with the improved CG.

89856
89857

Chip

[100 mph jet boat]

51 cool

what props??
how did it handle with the new COG setting??

[chipgibbs]

The props I tested today were M545, M447/3 & X642. The best speed was the M447/3 @ 51mph. The boat seam good under full throttle but, anything less than that and it feels like it's plowing.

Not done yet

Chip

[100 mph jet boat]

i think thats what tiqueman is trying to fix in this thread

http://forums.offshoreelectrics.com/showthread.php?38587-Fighercat-Cheetah-6s2p

[chipgibbs]

yup, I've been watchin that thread too