Jolly Cat set up.

[NorthernBoater]

Seeing as we have been have some problems setting up the Jolly Cat correctly lets start a thread on ideas to set it up correctly. So far I have had the best luck with a M447 prop. I have put some weight in the front and rear to try to spread out the weight. I will run it some more in a week when I have a water jacket.

[wickedgmc]

hopefully sometime next week I will be able to contibute

[Fluid]

Why not post the current setup and the issues encountered? Having it all in one thread will simplify things and make it easier for contributors to understand what needs to be done.


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[SJFE]

Well since I have run mine more than anyone else so far I will add something. I have a singe issue. When exiting the turns she starts bouncing. Now I have read & been in formed that is a result of a strut set to high. Wel in our situation there is nothing we can do about that. I have considered the following as of late. A mod to the stern and strut replacment. This is not an easy proposition. 1 you have to cut the gill barcket off of the stern. 2 the factory strut needs to be cut off of the stuffing tube. 3 extend the tube by sleaving it. This creates another issue. The wire drive will then unusable. So a conversion to a .150 cabe will be next. Now we have a big gaping hole in the stern. That will need to be glassed in. Once sealed a strut and rudder system will have to be installed. I have looked at a few. Keeping the dimentions close to the factory setup is a good idea. So the Fullers offshore unit should work along with the PIP dual rudder system. I have been debating adapting the set of duals I have for this mod. I imagine that an offset system may work also. IMO this is the only way to get ajustblilty other than weight built into this cat. Also IMO the hull is worth the work and effort. I just don't know if I can bring myself to put a saw to this boat. I really need more testing. When it comes right down to it..I will do what I have to.

[G Doggett]

I have only had one maiden voyage with my Jolly Cat so far and found the centre of gravity is critical to prevent porpoising or bouncing.
I have moved my batteries ( 24 cells ) forward from the original position to achieve a 33% balance point.
My boat by the way has twin counter rotating Feigao 8XL motors and surface drives behind each sponson so what works for me may not apply to a single central system.
Because this beautiful boat has scale dimensions and is therefore quite narrow I dont expect to be able to corner at full speed but it sure flies in a straight line with the two motors.
Graham

[NorthernBoater]

When this hull was first built was it designed with LiPos and brushless motors in mind?

[G Doggett]

Here are some shots of my Jolly set up as the Callan Marine twin turbine beast.
The inside shot shows the position of the batteries to achieve the 33% c/g.
With only K40 props she leaps out of the water on take off like a rocket.
Eventually I plan to run metal props and lipos so will be interesting to see just how fast it will go.
The last picture has the little Jolly sitting on top of her big brother Miss Longlite which has a single central motor( Zenoah ) and prop so this set up may be relevent as the big boat handles very well.
The bottom of the strut is level with the bottom of the sponsons and is parallel with the running surface and the c/g is also 33%.
OK the hull is not the same as the Jolly but apart from being almost twice the size it is actually very similar.
Regards
Graham.

[SJFE]

Nice cats guys and thanks for the info but I don't think it has any bearing on what we are trying to figure out. The twin setup is just to diffrent.

[G Doggett]

Hi SJFE
Is the factory strut glassed in during assembly ?
If this is the case could you cut the tube off the bottom and them make up a new one that is attached to the original blade by a couple of bolts to achieve a lower prop position.
If the bolts are up high enough they wont be in the wash.
I would hate to have to take to the hull with a hacksaw.
Just a thought.
Graham

[SJFE]

Fluid I am running a single 9Xl on s4-2p with the weight of the packs 25% foward of the stern on an x440-3 blade.

[Fluid]

...When exiting the turns she starts bouncing. Now I have read & been in formed that is a result of a strut set to high.

This is news to me. IME that behavior is usually due to a poor CG location (too far back) or a strut set too deep or at the wrong angle.

...The wire drive will then unusable. So a conversion to a .150 cabe will be next.

Why would you have to convert to cable? Wire will take a bend....

....Keeping the dimentions close to the factory setup is a good idea. So the Fullers offshore unit should work along with the PIP dual rudder system.

Why would you want to use that heavy dual rudder system with a single drive? The single rudder system of Fuller's would probably work much better.

I just don't know if I can bring myself to put a saw to this boat...

I don't blame you - but you may not have to cut anything. Prop choice and CG may fix most of the handling ills. I think you may be making this harder than it needs to be....

A photo of the transom as it is now set up would be helpful. :)
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[NorthernBoater]

What is the strut depth that people have used on other cats.

[Fluid]

The default position is - with the cat on a flat table resting on the steps - the bottom of the strut housing resting flat on the table. But this is usually not the ideal setting, just a good starting point. I find that most of my cats run better with the strut raised from 1/8" to 3/8" above the table, and sometimes angled up one or two degrees at the prop end. In conjunction with the right CG this usually stops the hopping and results in the best combination of speed and handling.

For highest speeds you will want to "fly" the bows a bit, running on the back few inches of the sponsons. The higher the angle, the faster the cat can be - but the risk of a blow over increases. A slight amount of bow elevation is okay with most hulls, but you may find that they then don't turn well at full throttle. This is because the bows are too high to dig into the water when the rudder is turned, so turns are wide. The cure is to cut the throttle a bit just before you turn the rudder, then get back on the throttle as the boat begins to turn. This technique is not uncommon for many racing hydros too.

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[SJFE]

Thanks for the input Fluid. Goes to show you can't believe every thing you read or are told. I have a few pictures for now. I will snap a couple more tonight.

[Darin Jordan]

OK, I give... HOW do you get to the strut adjusting hardware??? WHAT is holding it in???