Working the sponsons of a cat hull

[Tonymods]

Hi,

My boat, a bittburger 35inches (from PIP), has 3 steps on the sponsons. It is a really fast hull and stable on straight line. But it was not cornering well so I decided to check if the hull was thrue on a flat table.

well it is not flat at all, moreover the last step on the left sponson (left: when looking at the back of the boat) was 1mm higher than the right sonson. I cannot figure it out as the torque would already lift the left side...

The boat was turning ok when I was doing a left turn but it was terrrible on the right turn.

So how flat the sponsons should be? The two last steps must be equal in depth on the right and left side? :unsure:

Tony

 

[gil sonsino]

Tony there's nothing wrong with the set up of your cat.....some models like PIP,MHZ have this particular way of building sponsons on a cat.actually they are down scaled from full size boats.

What must be the same is the level from the left side with the right side of your sponsons.When I ran Aeromarine cats used to let the right rear sponson little bit deep than the left for torque compensation with good results.Your observation is correct the last step on your cat is higher than the two first so this is the original patter of this boat.

I'm building a Mhz Iceberg/Quick draw 35cc for a friend and its botton has the same description of your boat so keep easy and good boating.

Thanks

Gill

p.s lived/worked as dentist in Geneve for 5 years (cour de Rive)

 

[Tonymods]

Thank you very much for your input Gil,

It still seems wired when you check the boat on a flat table... Don't you think I should flat this thing a little bit so that both left side and right side of the tunnel will sit "true" on a least the last two steps.

"What must be the same is the level from the left side with the right side of your sponsons" Could you please clarify ?

I worked my tunnel that way and the last 7 inches are equal on both left and right sponson. the behavior was the definitely better...

Well "Geneve" is still the same. it is forbidden to run nitro and gas boats almost everywhere so I must go in France to run my boats.

I am working in the communication in Cours de Rive No 4 .....should we say the world is small... :lol:

Tony