Paramount with a jackplate and bracket problems

[maineidyl]

282821Started a thead in the general section and realized I probably should have here. I just installed a 6 inch Bob's jackplate on my 2003 Paramount with a 18 inch Stainless Marine bracket and VMAX200. At the lowest position on jackplate cruising around 3500 rpm at 35 this is how the cav plate looks. Problem is when I try take off at full throttle I am getting cavitation and when I slow down the motor gets swamped. This is with a stainless 21 no name prop with 1/4 vent holes in the prop. Going to try a 21 tempest and plug the vent holes to see if that helps.

[SunnyDaZe]

I also have a paramount, it does cavitate as well trying to get on a plane or whole shot it. I think my issue is my motor sits high, its on the middle mounting holes on a Merc 250, however someone told me if I bring it a step down it should take care of it due to the step hull on the back of the paramount. I just bought a jack plate myself and wanted to see if it did help once I installed it in the neutral position, and being able to go up 3-4 inched up or down. BTW: its a 25" shaft Merc



282821Started a thead in the general section and realized I probably should have here. I just installed a 6 inch Bob's jackplate on my 2003 Paramount with a 18 inch Stainless Marine bracket and VMAX200. At the lowest position on jackplate cruising around 3500 rpm at 35 this is how the cav plate looks. Problem is when I try take off at full throttle I am getting cavitation and when I slow down the motor gets swamped. This is with a stainless 21 no name prop with 1/4 vent holes in the prop. Going to try a 21 tempest and plug the vent holes to see if that helps.

[lance]

I had similar problems with my Checkmate. I have a 12" Stainless Marine mini setback and a 6" CMC power jackplate. In your pic, the engine looks a little low but your symptoms indicate the engine is too high. I would try lowering it a bit and see what happens. I run with a heavy load and tried a bunch of different props. Most were blowing out on hole shot just at break over. I ended up using a Bravo I with PVS holes drilled which works amazing. A 22" Bravo will run similar RPMs as a 21" Tempest. Large diameter, large hub props with a barrel flare like a Bravo I, Bravo XS, Hydromotive Q4XOB, and etc should work well. PVS holes will be needed.

Another thought is have you tried different trim settings for hole shot? My Stainless Marine bracket had 5 degree of negitive angle built in which was too much for me. Normally you would trim all the way negitive for hole shot but Yamaha's have a lot of negitive trim already. Try a bit of positive trim for hole shot just to see what happens. I ended up adding a 5 degree wedge to compensate to the 5 degrees in the bracket.

I also had a problem dunking the engine when coming off plane. I added a B-man foil (similar to an Allison) to the cav plate which helped. I then tried an Eagle One drag plate that really helped. The Eagle One plate is huge. I don't like the looks but it really works.

[south599]

yep a Bman foil for the cavitation plate and a skid plate for under the jackplate will help with holeshot, cavitation, and the wall of water when stopping.

[Allyda]

This is my first attempt at fabricating myself a holeshot plate or, 'skid plate,' as you called it. Upon suggestions from others here on S&F to keep my bow down during holeshot, and especially prevent backwash from coming over the transom upon stopping I thought it was worth a try. I don't think I did too bad for it being my first one. Now I just hope it works.

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[maineidyl]

Looks great. Would have never guessed it was home made.

[lance]

Allyda, How did you attach it?

Here are pics of the one I made from anodized aluminum angle and a kitchen cutting board. I've added more setback and need to change it around.

283720283721283722

[Allyda]

Allyda, How did you attach it?

Here are pics of the one I made from anodized aluminum angle and a kitchen cutting board. I've added more setback and need to change it around.

283720283721283722

It looks like you designed it well, very professional looking! I love the ingenuity on this site!

Since the older Bob's two piece on my boat is about to be replaced by an 8" Hydrodynamics MajicJack, I decided to try an idea I had to make the installation more cleaner looking. I bought some 1/4" x 20 (coarse) stainless steel bolts, flatwashers and lockwashers and a tap to make threads for each bolt. My jackplate's aluminum is just under 1/2 " thick. So on each side I drilled 3 3/16" holes up into the center of the bottom of the part attached to the boat 1 & 1/2 inches being careful to keep my drill straight, carefully tapped them out at least to 1" of threads. I then had a friend hold the holeshot plate up in position so I could mark on it where to drill the holes. Once the 5/16" holes were drilled in the holeshot plate I then just bolted it to the bottom of the jackplate.

Where these holes are drilled is far from any high stress area and this way I don't have any aluminum angle present to interfere with the jackplate's up & down adjustments. Each bolt tightened up well, it isn't going anywhere. When I change over to my majicjack though I'll probably have to mount it differently as the bottom of it is shaped differently than my Bobs.

[lance]

Thanks for the details.
I've replaced my Hydrodynamics 6" plate with a Stainless Marine 12" bracket. The problem I have now is bottom of the CMC plate drags in the water when the plate is all the way down. It only drags on hotshot and slow planning speeds. I need to add a skid plate under just the CMC plate that will move with the plate. I'm thinking about how you attached yours.
Thanks

[rgsauger]

Allyda, have you run your Shadow yet with the new plate installed? How did she do?

[Allyda]

Not had the chance yet. I'll be cutting the new carpet that finally came in (I ordered a darker 'gun metal grey' color my guy didn't carry in stock) I picked up 2 days ago. I also ran into some special luck by coming across a fellow that had two props I wanted. Wait til ya hear what they are and what I paid for them:

Since I already have a 15 x 28p Hyperdrive 3 blade Hoss I'd been looking for another for awhile now for a spare. Well, I found one but, it's a 3 blade Triton in 14 & 1/2 x 28p. and bought it.

This other one I've been searching for since I've owned my boat, the elusive Hydromotive Intimidator Quad 4 O/T hub 15 x 27p. Well, this guy had both of these. There's not even a nick on either of them. I paid only $145. for the Hoss!, and get this, only $200. for the Elusive Hydromotive!!! The Hydro even still has the "Intimidator" decal on it! -never been ran. How's that for some luck eh?:reddevil: I had to dip into my reserve funds to get them but hey, who could pass up a deal like this!?

As for when I'll be back on the water? I expect if all goes as planned by the first of the month, which is great cause my birthday's in October. I'll of course let y'all know how she runs with the new mods and holeshot/skid plate then. I expect much less bow rise on takeoff and no more backwash when stopping.:thumbsup:

If any of you get to run yours before I have the chance to run mine I'd apprectate hearing about how well it worked. Thanks in advance.
Ally.

[SunnyDaZe]

It looks like you designed it well, very professional looking! I love the ingenuity on this site!

Since the older Bob's two piece on my boat is about to be replaced by an 8" Hydrodynamics MajicJack, I decided to try an idea I had to make the installation more cleaner looking. I bought some 1/4" x 20 (coarse) stainless steel bolts, flatwashers and lockwashers and a tap to make threads for each bolt. My jackplate's aluminum is just under 1/2 " thick. So on each side I drilled 3 3/16" holes up into the center of the bottom of the part attached to the boat 1 & 1/2 inches being careful to keep my drill straight, carefully tapped them out at least to 1" of threads. I then had a friend hold the holeshot plate up in position so I could mark on it where to drill the holes. Once the 5/16" holes were drilled in the holeshot plate I then just bolted it to the bottom of the jackplate.

Where these holes are drilled is far from any high stress area and this way I don't have any aluminum angle present to interfere with the jackplate's up & down adjustments. Each bolt tightened up well, it isn't going anywhere. When I change over to my majicjack though I'll probably have to mount it differently as the bottom of it is shaped differently than my Bobs.


Lance is it possible to post pics of you paramount with the bracket setup. Im installing one now, just want to get some general measurement as to where you mounted her. Will be greatly appreciated.

[lance]

SunnyDaZe, I have a Checkmate not a Paramount. I'm running a short 16" mid. Since I have a Sportmaster case, I set my jackplate and bracket so the prop shaft is even with the pad when the CMC plate is about at half travel. I can go up or down about 2-1/2". Here is a pic of the SM 12" bracket, CMC power jackplate and a 5 degree wedge to compensate for the negative 5 degree built into the bracket. I still have to make a new skid plate.

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[SunnyDaZe]

SunnyDaZe, I have a Checkmate not a Paramount. I'm running a short 16" mid. Since I have a Sportmaster case, I set my jackplate and bracket so the prop shaft is even with the pad when the CMC plate is about at half travel. I can go up or down about 2-1/2". Here is a pic of the SM 12" bracket, CMC power jackplate and a 5 degree wedge to compensate for the negative 5 degree built into the bracket. I still have to make a new skid plate.

295682



Thanks Lance.......You see to put much thought and effort into it i see. I guess its all trial and error.