seanv

so to all who thought it wasnt that bad take a look!!!
a tab wont stop this crap! http://www.justanothertoy.com/videos/TheHop.wmv

seanv

any comments fast eddy? chrome cat? quest?

wannabe

You can actually see the stern try to hop up as the bow comes down indicating too much lift in the stern. Wow, thats bad.

Is the hull straight? Hook, rocker etc?

Wannabe

seanv

oh it's fine now after i did exactly what they said never do! but i told them i would post the video as soon as i had it to prove it was unsafe.

ROTAX454

It appears to me that the problem is directly related to stern lift. That lift is created by the wrong prop. Could be pitch and/or diameter of the prop. Sean, I would still work with a prop specialist to work on your boat/motor combo to insure that the problem does not come back. My humble .02

I certainly agree on the tunnel tab. A possible hazard laden band aid. Using the tab (without extreme caution) on a cat under very high speed conditions can be met with dangerous results. Again, my humble .02

seanv

rotax, i really dont know if props will fix it right now its good except for hittn the rev limiters. i'll run it like this for a while to get used to this boat. then step up the pitch and see what she does.

tuffenuff355

looks like you need a prop with a little less stern lift , with the boat porpousing like that a tunnel tab probably will help but is not the answer speak to a good prop guy or send yours out to get redone

seanv

im borrowing 32bravos right now so the next step is to call a couple of prop people and see what they think like you said. i think 34 bravos would give me the top end speed but like i said before, i need some seat time in this to get used to it before going any faster.

aex

My Chris Cat did the same thing , but only in fresh water . At a race in Buffalo ( 1990 ) I tried a kilo run and was porpoising out of control with way jacked up # 5 drives . A subsequent prop change helped it . Went to a smaller diameter . Hope this helps .

blownboat

update, sean still has the boat and has got comfortable driving it. after adding several comforts like t.v. lighting etc and new topends on the engines the boat is coming along. as for ride/speed, that thing scoots along at 115 in az summer temps with engine left. he's looking at 34p bravos or maybe p5x's. still turning them in and it handels great.