I'm sure this has been ask a million times (CG)

[Fastfish]

What should the CG of my 37" Genesis be. Please help me calculate.

[Jabbo]

Don't know exactly prob between 9-10 in from back of sponson, use the search and you will find all the info and more you need. There are a lot of genesis/daytona build threads.

[Mattwarner]

Between 9-12" based on what I managed to find, wanted to know the same thing myself.

[Diesel6401]

28%-30% the length of the hull is a good starting place for cats/monos. Measure the hull tip to transom not including hardware or the rudder standoff. Take the length x the %. Once you get the number measure foward from the transom. That's your cg point. Move the batteries around so that the boat balances at that mark slightly nose high.

[Fastfish]

Ok...mine is at 10"-11". I move the rudder up level with the sponson. Tinkered with the servo's sub trim to help it run straight. I'll fine tune that on the water. One thing I've learned over the years flying Nitro Helicopter is to fine tune the servo's...The rudder servo should be simple. Man I love these rc offshore boats!

[Fastfish]

Thanks Diesel! You have really been a great help! At what point on the transom are you measuring from? The end of the sponson or the end where the rudder hardware connects to the boat?

28%-30% the length of the hull is a good starting place for cats/monos. Measure the hull tip to transom not including hardware or the rudder standoff. Take the length x the %. Once you get the number measure foward from the transom. That's your cg point. Move the batteries around so that the boat balances at that mark slightly nose high.

[JIM MARCUM]

But, rudder should be around 1 1/2" below the prop shaft, which should be about level with the bottom sponsons. Change CG moving batterys fore/aft. JIM

[Fastfish]

Thanks Jim! I would need have to cut the rudder down on this HK Genesis...The prop is level with the sponsons now and the rudder is 2 1/2" below CL of rudder.

[Make-a-Wake]

28%-30% the length of the hull is a good starting place for cats/monos.

I thought cats liked around the 32-35% range? Could very well be wrong...............

[Rumdog]

It all depends in how fast you plan to go. It can vary quite a bit.

[JonD]

I am getting good performance with no porpoising on my Genesis with CG at 33% (measured from the rear of the sponson, not the transom). Anything less than this and I start to get some porpoising.

Jon

[JIM MARCUM]

Depending on the rudder, I usually only leave 1 1/2" of the rudder below the strut shaft. If you are using the water nipple to cool your ESC/motor, don't cut above the H2O intake hole. If you see a hole in the bottom of a shortened rudder, carefuly fill the hole with epoxy. Too much can clog the intake. Or you could try these from OSE http://www.offshoreelectrics.com/pro...prod=ose-80515 JIM

[JonD]

Jim,

On a cat like the Genesis, does this mount on a sponson? What height? Do you mount it so that the flat bottom of the pick up (where the inlets are) is flush with the under side of the sponson?

Wouldn't the water flow be broken up with air when the boat is planning across the water?

Whilst the enlarged water pick up holes that did recently to my stock rudder work well and heaps of water is now passing through, I am sure that this must be causing much greater force on the rudder because I am even starting to bend brass safety screws (the M3 nylon screw shears through). So I have been thinking about using some other water pick up method.

Jon

[JIM MARCUM]

I' running these on my Black Jack & Apparition & they seem to be working well. I mounted mine flush with the bottom of the transom. Like this:
JIM