Quote Originally Posted by Per View Post
Thanks for your interest in this matter!

Yes Google translate is a very good thing isn't it!

zul8tr don't pay to much attention to how the boat rides in the video, I think the speed is only somewhere around 25knots and I was slowing down when I passed the camera. I only included it so you could get a good view of the boat.
The Penta engine in the video is still in my workshop for surgery, it had a severe case of overheating, right now the boat is powered by OMC.


Lets answer some questions:

Setup:
Engine, OMC 56ci 70hp from -92 with trim and tilt, completely stock.
Gear ratio 2.42
WOT rpm between 6300 and 6600
Prop Unknown brand over the hub cleaver 14"x24"
Prop shaft height is 2"-2,5" above bottom. did not find any good picture, sorry!
Top speed is so far 47knots with very little positive trim, (trimmed out from prop shaft parallel to the bottom)

Video of the gear case:
It is quite hard to see the water surface since the lake was like a mirror that day but one can see a shadow just by the leading edge of the gear case.



Another view:

http://www.youtube.com/watch?v=27aB7lmphug

Lack of power and slightly overweight, sure just like me I was told that when the hull was built it only weighed 75kg, that was before any of the reinforcement was added (transom, knees, stringers and such) but it was built around -83 so I guess no one really remembers...
I think the hull it self only weighs around 150kg is that heavy?

FastJeff57, about the porpoise, yes, maby the wedges are there to control some longitudinal instability? (speculation from my side)

FrenchPhil In what kind of cats are the steps /wedges still being used? do you have any pictures??

The fact that someone removed the aft portion of the strakes feels like he (most likely a guy, right?) was trying to create more bow lift.

Got myself a new prop for the cat today, a Winrace 14x25" slightly modified by previous owner, lets hope I get to test it before the winter arrives!
150 kilo not bad for just the hull. But when loaded at 325 kilo I assume that is engine plus gas and other supplies. That plus 1 driver at 86 kilo (guess) is 411 kilo (900 lbs) rather heavy.
The speed and rpm you are posting are not that bad. Using prop speed calc just for a ball park with 6600 rpm at 10% slip is about 56 mph. So your measured gps speed of 47 knots (54 mph) is not to shabby which gives slip about 13 %. That can improve. The 2.42 gear is to high (per Frenchphil and I agree). The 14x 25 might not be as good as the present but try it and increase the engine height and pitch out. With the 25 pitch you need the rpms to go up.

http://continuouswave.com/cgi-bin/propcalc.pl