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View Full Version : Why are some Bottoms so much better than others?



FoMoCo
05-09-2002, 03:33 PM
Anyone know whats makes different boats bottoms better than others? Like an Eliminator to a Tahiti? Or a Rogers? I have heard those where 2 of the best bottoms built in the 70's. Jack At MPD said theres like a 5mph diiference between those boat bottoms( Eliminator & Rogers) and others.
Just Curious??

HYDROMOBILE
05-09-2002, 07:13 PM
They are just like a girl some bottoms are buit for speed and some built for comfort,

HBjet
05-09-2002, 09:34 PM
If it's the same mold, I think alot has to do with how they build the boat, materials, curing time, condition of the mold, etc.
HBjet
[This message has been edited by HBjet (edited May 09, 2002).]

flat broke
05-10-2002, 07:03 AM
Originally posted by HYDROMOBILE:
They are just like a girl some bottoms are buit for speed and some built for comfort,
Classic! http://free.***boat.net/ubb/smile.gif
Chris

69 Elim
05-10-2002, 07:18 AM
Originally posted by HYDROMOBILE:
They are just like a girl some bottoms are buit for speed and some built for comfort,
Never saw a speed bottom I didn't like.

AGGRESSOR JETS
05-10-2002, 08:13 AM
Are we talking Tunnel to V or Just Bottoms in general. If in general-Its the Mfg. Design and Care of his mold. In design quick on plane time- sound lift design to full rise minimal wetted surface. Hydro had it "Right On"Just like women.
Most Builders have hooks in the molds- know it and leave it, may-be by purpose(safety so said)or lazy to remove.
Roger was old school, sell your hull to racers win and the rest will follow.
Roger took top care of his molds, molds did not see the sun, and were maintained for Performance.
A hull that just started to push big numbers was Kalawian built by Dave Kalawian. David passed away shortly after and many racers felt a hole in the market. Enter Bob Leach, Eliminator- Bob came from the same concept background, my brother bought his second or third hull on the market for Lake Racing. Bobs buyers backed the hull with true Numbers and he has maintained a high level of quality with performance numbers to back it.
Straight Bottoms are 3-5 MPH. Think of the concave ski- when it came out it was the hot number and all it did was suck you down. Harder to get up on due to the concave effect.

FoMoCo
05-10-2002, 09:15 AM
Thanks Aggresser, I am trying to figure out why my Kachina(1977) Is not working out right. I had her upside down( the boat) and there was no hook, from 4 feet back. But when I got her all together with a new ride-plate and shoe combo, along wuth new pump, and motor, and paint etc.. It has a porpoise issue? It wont porpoise AT ALL IN 6 INCHES OF CHOP ON THE WATER( 76 mph with gps)?? But When its flat out it will suck the boat down hard and start to porpoise anything above 60 mph???? I dont have a Diverter or droop, but I know its not supposed to do this! The ride plates been all over form 4 degrees up to where it sits know at 0 degrees. Could my 1/2 back cut shoe be to much for it? Oh ya I am runnin an MPD open center loader grate. I also notice a less change of porpoise when I drive her by my self( the boat)????

RR1/ 001
05-10-2002, 09:41 AM
You say it`s been at 4 degrees up witch is on the + side, to 0 degrees. Try going the other way (down). I had a sunkist jet that I had to go - 0.030 (down) to get rid of the porpoise. It kept the boat from standing up on the hole shot and took out all the porpoise.
Make sure that you have good support on the ride plate because any flex will cause the same thing.

RiverDave2
05-10-2002, 09:48 AM
FoMoCo, I don't want to mislead you by making you think that I have ANY knowledge of jetboats.. But a thought crossed my mind. Could it possibly be poor weight distribution? Have you tried throwing some weight up under the bow? If it gets rid of it, then you might want to move your motor a little further forward some of the hardware to better "balance" the boat.
In my case it did help, but I'm sure as hell not going to move my motor so I have a couple sand bags in my anchor locker and a plate to add a little "transom lift" when needed.
RD

HavasuBarney
05-10-2002, 09:53 AM
Little girls grow old, gravity is a bitch!

sgdiv7
05-10-2002, 12:18 PM
My buddys boat had the same problem at the races in phoenix and he fixed his by changing to a smaller grate. The way he explained it to me was there was to much water getting to the pump which caused the back of the boat to lift and it porpoised all the way down the track. At the lake he never had a problem. But what do I know, I am a V-DRIVE guy.
Bill

greg shoemaker
05-11-2002, 08:08 PM
Where do the inside strakes begin and end?Greg

FoMoCo
05-12-2002, 04:47 PM
I just checked with the tape measure. From the front they start 3ft back. They end 16 inches from the back of the boat. What are you gettin at? I am now wondering if my MPD grate hangs down to low?

flat broke
05-12-2002, 08:45 PM
Originally posted by FoMoCo:
I just checked with the tape measure. From the front they start 3ft back. They end 16 inches from the back of the boat. What are you gettin at? I am now wondering if my MPD grate hangs down to low?
Call Jack. From what I've read of the posts here it looks like you've tried a lot of variables without any luck. You and I both know that Jack will take the time with you to set you straight. Good luck, and get that diverter already http://free.***boat.net/ubb/wink.gif
Talk to you later,
Chris www.liquidaddiction.net (http://www.liquidaddiction.net)

old rigger
05-15-2002, 09:09 AM
FOMOCO,
funny you should mention Rogers and Tahiti together, most people don't relaize the connection between the 2. Besides the fact that Roger Weiman and Dick Schuster (Tahiti) built the first ever v-bottom jet drive, the Rogers bottoms evolved from the little deep nose 16 Tahiti that he had streched into his 17' footer. (and that 16 Tahiti bottom was a splash from a Glastron) Schusters shop and Rogers dad's shop, Weiman's custom boats, were across the street from one another in Bellflower, in the early days.
After a few years of having his racers thrown through the gunales (jack mc being one of them) when the boat would spin out due to the sever bow steer that the deep nose would deliver, Roger removed it, and streched the 17 in to the 18, the boat that dominated circle racing well into the 80's. These were not the same as Eliminators bottom. Years of r&d made Rogers stuff the ones to beat, and splash as well. The boats he sold to the every day boater were just as nice as his race hulls, if you have a chance to pick one up and are in the market for a little 18, buy it. They're a lot of fun.
Nobody took better care of their molds than Roger did, always covered, and always under roof, and his laminating sehedule was envious too. Of course low production numbers allowed him this luxury where most others only claimed to do the same.
I've never seen anyone build hook into the bottom of their plug. Not in the So Cal Custom boat thing. Usually occurs from one of 2 things. Crappy lay up or the part was pulled from the mold to soon. Make that 3 things, sitting incorrectly on a trailer can cause hook too. Maybe 4, a rigger can put a hell of a hook in a boat by incorectly installing the intake in a jet.
It would have been interseting to see what Roger would have done in the bigger boat market of today. The biggest boat he offered was the 21, tiny by todays standards.
A-jets is right, Roger, now retired, was definetly old school. Thank God someone still is.