Catamaran CG - How to dial it in

[Loki]

Hello all!

Well I got my Jolly Cat built and man what an absolute blast!!!

Anyway I'm trying to figure out how to get the CG just right on her and wondered if any of you had a quick easy way to do this or if there was a tool you all use. I had an application on my IPhone that will tell me what % something is off, but not sure how 'true' that number is.

Thanks for any advice or guidance on this, I've done the search on here but I can't seem to find the key words to see if someone else has already posted on how this is done.

Loki

[Jeff Wohlt]

Does it have stinger struts or regular? It is all about how the boat rides and corners. Most stepped cats do not look like they ride as high in the front as non-stepped but you should be able to see most the the front half of the hull out of the water.

Fluid might pop on here...he knows cats best.

I usually shoot for 35% from the rear and run it and move the cells back or forward until I get the attitude for the hull to not run wet....too far back and over she goes when a gust of wind hits it at top speed but then again...it depends on what top end you are getting out of it.

You need to dial it in so you can run pretty much full throttle all the time with exceptions in the corners and even then you want to be giving it most of what she has or you heat up the esc to much when dogging it around.

Those are sweet cats forsure.

[kevinlew211]

I just want to add some info, which i got a mistake with, 35% from the end of the tunnel NOT from the transom, again, thanks Jay for helped me with this

[Jeff Wohlt]

Hmmm....I always set mine from the transom to the front. I balance it with fingers on each side to see where the boat balances.

[DISAR]

I place the boat resting on a brass tube on a table and see where it balances quite accurately. For the jolly cat i suppose around 30% from back of sponsons should be ok for starting.

[Jeff Wohlt]

Seems if you start from the front my mean machine at 35% would run wet as heck. My marks are somwhere around 7" from the transom...where all the weight is. I move my cells forward until I get a decent balance amlmost whee I want the boat to ride on the water.

Some cats have longer rear ends than actual sponson. Do you mean start it there or actually from the front of the tunnel?

[kevinlew211]

i believe the Jolly cat the transom is far behind the sponsons, its not like those AM hull they ended at the same place, for that case, CG must start measure from the end of sponsons NOT transom

[Jeff Wohlt]

Absolutley. I was not explicit enough. You will be there at around 35% no matter what until you see how it runs for your conditions and how you run a boat. Also, your transom is always where the power/drives are connected to...not some cosmetic extended hull for looks. Good point to be clear about it.