View Full Version : Parts needed for jet boat....
Doug H.
08-20-2003, 10:24 PM
My buddie has a 21ft. 76 charger daycruiser exactly like Jetboatrich's, 455 olds with a wj jacuzzi pump. no diverter or rideplate the boat porpases (sp) real bad after plained, he wants to change part of the pump to berk or aggressor and needs a ride plate with a diverter and maybe a droop, will this help him with trimming the boat and keep it stable ? any suggestions will be welcomed please help me out. :) :)
BIGAMIST
08-20-2003, 10:35 PM
Get rid of the olds,that should fix everything :p :p :p
My understanding, yet limited is that if a boat porpuses then that is signs of a hook. I asked about this in prior strings and the best way that was brought up on how to check for a hook is to use a straight edge and check points all over the hull.
Doug H.
08-20-2003, 11:03 PM
Thanks Bigamist for your honesty :D dgie i hear what your saying but don't you think hook or no hook that a change out of the jacuzzi to berk with diverter and rideplate help ? that's what Jetboatrich has so i just thought it would work for Jeff's boat, he really needs to cure this problem. :)
Sorry doug thats beyond me I am still trying to figure out what a ride plate does. Porpusing can be caused by a hook from what I am told. Bigamist should not have cracked on olds because I was going to and he beat me to it :rolleyes: Really though my olds has stood up pretty well I got water in it twice due to not having that Basset "T" valve and it has came thru unscaved both times. It is a heavy motor, but hell its all I got right now, and like Moneypitt said it is a pleasure boat and really its good enough for me to lure the chicks in.
Snorider
08-21-2003, 05:36 AM
Even though a hook can cause porposing, that doesnt mean changing the pump will not fix it.
If you add a ride plate, and a diverter, possibly even some negative wedge, you will be able to remove all the porposing. Just keep lowering the plate until the porpose disappears.
You might lose a few mph, but it will stop the porpose.
Squirtcha?
08-21-2003, 06:58 AM
What about having the Jacuzzi reworked? Here's a link of someone going through this process now.
Jacuzzi rework (http://forums.***boat.net/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=11;t=003696)
BrendellaJet
08-21-2003, 07:13 AM
or,your friend could buy my 12WJ diverter. Brand new piece, never been used. Comes with the manual control.
Jetdriver
08-21-2003, 07:28 AM
Are we talking about the baby blue one that was in the cove for a little while at CBBB?
Moneypitt
08-21-2003, 07:55 AM
A few years ago I worked on a horizon, 18', BBC, with a bayjet. It had a bad bouncing problem, like yours. We used electro-hydrolic ride plates, one on each side, with a control on the dash. Problem solved....They were about 14" wide, and really smoothed out the ride, in fact the boat went faster with the plates slightly down for stability......I think your problem will continue even with the changes,(expensive) that you're talking about. Your set up is all there, just needs a little help.......Moneypitt
Floored
08-21-2003, 08:00 AM
I'm happy with my wj but its been reworked for berk droop and diverter and has rideplate. at mid speeds if diverter is set wrong I'll get a little porpoise but a slight up on diverter and it goes away or you can power out of it, even with a 455 olds. Having the 455 is great, if you lose a race they won't brag to their friends, and when you win they never admit to racing you.
Doug H.
08-21-2003, 10:18 AM
Shawn, PP, Jetdriver, yes that is Jeff in the blue charger and needs a little help with his porpusing action.
Floored
08-21-2003, 12:37 PM
if you ever saw the hull shape on my Biesemeyer
jet you could see that it traps air like a gullwing. with the extra length of the rideplate out back its like having a little extra leverage to help stop the rocking effect. its similar to a cav plate on a flatbottom to give the boat a set at speed. it also helps reduce drag from the pump in the water at speed. you could try the rideplate first and add a diverter or the other way around as money permits. I'll try to find the pics of my setup.
Doug H.
08-21-2003, 06:17 PM
Do they make a ride plate for a jacuzzi pump ? and thanks for all your input guys. :D
Mohavekid
08-21-2003, 07:08 PM
I had the same problem on my Sanger Mini-Cruiser. Low speed was smooth, top speed was smooth, anything in between was a wild ride.
I have a Berk "e" pump with the factory cavitation/ride plate.
I tried a Plave Diverter which solved the problem, but required me to run the PD full down to stop the porpoise. I could feel a real loss of forward thrust when trimming it down though. I ended up adjusting the cavitation/ride plate with a pretty severe down angle which smoothe the ride out dramatically.
I don't have a speedo or GPS to check for any change in top speed, it does not feel any slower.
This winter I'm thinking of trying the e-rideplate and shoe kit from hi-tech. I thought I would attach som hydraulic cylinders to the plate to make it adjustable from the dash, similar to a trim tab setup.
Bottom line, fine a ride plate or some fixed trim tabs and adjust them down until the porpoise stops. Placecraft20 on the boards had the same problem and did the fixed tab deal with Rexone and says it cured his problem and added some speed.
Good luck.
Rich
Im sorry I am retarded or something, but What is a ride plate, what does it do and what does it look like? I read everything on this string and am still lost in the sauce.
Mohavekid
08-21-2003, 07:20 PM
A ride plate is a flat plate about 10 inches wide and 12-18 inches long.
It attaches to the intake of the pump and extends rearward. It attaches to the pump at the rear via a cradle. It is adjustable, up/down and provides aditional running surface to the boat. At high speeds, it allows the hull to "rock back" on the plate and get more hull out of the water for less drag. Check out this link for a pic. linkhttp://www.cpperformance.com/search_results.asp?txtsearchParamTxt=ride+plate&txtsearchParamCat=ALL&txtsearchParamType=ALL&iLevel=1&txtsearchParamMan=ALL&txtsearchParamVen=ALL&t xtFromSearch=fromSearch&btnSearch.x=16&btnSearch.y=4
Hope this helps.
Rich
malcolm
08-21-2003, 07:21 PM
My Spectra 18 porpoises really bad, but the diverter all the way down stops it. I'm going to fool around with a ride plate or some trim tabs over the winter.
RandyH
08-21-2003, 07:32 PM
dgie:
Im sorry I am retarded or something, but What is a ride plate, what does it do and what does it look like? I read everything on this string and am still lost in the sauce. Here you go dgie. Ride Plate
http://home.pacbell.net/jmcclure/CradleOnPlate1.jpg
You can find good info here: :D http://home.pacbell.net/jmcclure/
Good Luck
RandyH
Is it possible to put a loader grate on backwards? 12wj if so what would would it do as far as performance. Randy i clicked on loader grate on that link you provided first and is starting to make me think. I bought this boat from someone who knows less about jet boats then I do. I do not know if he put it on right after he took it off.
RandyH
08-21-2003, 08:01 PM
Well dgie, I am certainly no expert, thats why I rely on Jack at MPD. But my guess would be that the way they bolt on to the suction piece, it really would be hard to get it wrong. Not to say however that its not hanging down too far below the keel line. I thought I remember somebody saying they some dont even get below the keel line. Mine is about .25 inch below. There are many diffenent types also. Take some pictures and email them to Jack. He can help you out and he does great and bowl work too. wink
Good Luck
Randy
[ August 21, 2003, 09:09 PM: Message edited by: dgie ]
when I am saying the loader grate I am only talking about the grate not the piece the pump mounts on. I will take a look at it tomorrow. The ride plate looks like something someone could easily make themselves.
BrendellaJet
08-21-2003, 09:38 PM
The ride plate could be made by just about anyone, some may not be as pretty as others...installing it would be the problem. I have the hardware form my old WJ ride plate, decent piece, needs polishing, it requires a little fiberglass work to install though-probably not the best design, but likely not the worst. Ive seen several other boats with the same design(a couple of Hondos in particular)Ive got a diverter for sale too, cheap and new!
Floored
08-21-2003, 09:45 PM
if you go to Hot Boat image gallery under jet boats look under floored and I posted pics of my jacuzzi showing the ride plate and how it attaches to pump :cool: hope I did it right anyways. first picture post
BrendellaJet
08-21-2003, 10:14 PM
Floored-here you go
http://www.***boat.com/image_center/data/520/997floored_pump_2-med.jpg
Cant see how it attaches to the intake/bottom...How does your boat run, specs? Did you notice an improvement with the droop?
as Brendellajet mentioned above how is it attached to the bottom? can you snap a picture and how you attached the plate to the pump underneath. Also what are the 2 shackle looking things that attach the mount on the pump to the plate and are they adjustable ? and where can you get them from. I have my saw and drill out and all ready to start making my own :D
[ August 22, 2003, 12:42 AM: Message edited by: dgie ]
Floored
08-22-2003, 07:36 AM
the front of the ride plate attaches to the rear of the intake where it was machined down. at the rear those are a turnbuckle setup with a clevis and pin attachment to the mounting points. the mounts take 1 screw into the center to attach. the hardware came with my boat but its a nice and fairly clean setup. I've never had a chance to gps or radar it but it runs pretty good. plate is 8 x 26 x 1/4 thick never ran boat without the droop so can't say, she does wiggle just a little at speed but not enough to soil my shorts. Thanks Brendella for pic I just learned last night to post pics in HB photo area. Yes its a 455
Floored
08-22-2003, 08:15 AM
added a couple more in image center that might help. lotta jacuzzi's out there wink
floored I assume that it is not movable up and down, where you can change the angle, is this the case with all rideplates?
Floored
08-22-2003, 01:02 PM
yes its movable you just turn the center part of the turnbuckle and it can be adjusted up and down and then locked with the nuts. about an inch of up and down travel to set angle
Is the front of the plate is mounted solid to the intake? if so the plate would torsion, just trying to get a good understanding on how this setup is mounted.
Floored
08-22-2003, 10:47 PM
yes it is mounted solid in front. the plate can take a small bend when adjusted. you can alter the angle of the cut in the intake to mount it to match your desired plate angle, but each hull seems to have different angles that work for it. trial and error. Squirtcha picked up alot of speed and stability just by adjusting his plate and he's willing to share info also
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