WELCOME TO RIVER DAVES PLACE

MMW cavitation plate vs tunnel tabs

Husqy510

Well-Known Member
Joined
Aug 9, 2011
Messages
602
Reaction score
593
We have an 03 26' Howard cat which we rigged for the 1st time last year. It has a N/A 540 which made about 720 on the dyno (probably mid 600s with accessories and exhaust). Currently we're spinning a 28 prop which works great once on plane, but with 4 adults it struggles to rollover. I was thinking about adding a cavitation plate to the outdrive or fixed tunnel tabs. I'm leaning towards the cavitation plate because I don't want to drill a bunch of holes in the transom. I'm looking for something that will help with coming on plane and decrease the load on the outdrive.

Any suggestions?
 

2FORCEFULL

Well-Known Member
Joined
Jan 26, 2008
Messages
26,835
Reaction score
13,842
i've had great results with tunnel tabs... they handle ruff water better as well as get on plane better...they stop it from kite ing off wind rollers
 

$hot

To say what? :)
Joined
May 25, 2018
Messages
990
Reaction score
2,050
would be great to see some pics!
 

02HoWaRd26

Well-Known Member
Joined
Dec 19, 2007
Messages
8,065
Reaction score
16,308
Simply put, there is zero downside to the MMW wing plate, and it’s 300$ and a couple small holes drilled into your drive. I’d definitely try that first.

However with your hp and boat, wonder if your X isn’t a little too high.
Stock lower or a shorty?
 

Husqy510

Well-Known Member
Joined
Aug 9, 2011
Messages
602
Reaction score
593
The boat drives great and has no porpoise. I'd actually like to try a 30pitch because the motor pulled 5600rpms easily and I'm sure I could trim it up a bit more, but I assume that would make it even harder to get on plane
 

ONE-A-DAY

Well-Known Member
Joined
May 21, 2010
Messages
16,621
Reaction score
20,862
Try a max machine works wing plate, cheap, easy to install and makes a big difference before you go and spend more money and more headaches than you need to.
 

2FORCEFULL

Well-Known Member
Joined
Jan 26, 2008
Messages
26,835
Reaction score
13,842
LOL... after looking at the transom, I have the fix,... but it'll just start the shit show of yard dogs barking....
 

2FORCEFULL

Well-Known Member
Joined
Jan 26, 2008
Messages
26,835
Reaction score
13,842
the getting on plane problem is the big noches in the sponsons
 

THE Cat Sass

Well-Known Member
Joined
Mar 7, 2018
Messages
101
Reaction score
188
I have some experience with the MMW cav plates on a 28’ Speedster. The worked exactly as advertised to help control the blowout prior to flop. That said if you don’t have the low end torque to blow out the prop the plates wouldnt be the answer. It was a game changer on the 28 for sure, I could essentially get a little momentum, set the sticks to 1/4 throttle and it would roll right over.
 

Husqy510

Well-Known Member
Joined
Aug 9, 2011
Messages
602
Reaction score
593
Just ordered a polished cav plate from MMW which I hope to install on Friday. I'll update the post after we try it
 

Husqy510

Well-Known Member
Joined
Aug 9, 2011
Messages
602
Reaction score
593
A friend with a lot of experience setting up performance boats mentioned the cavitation plate can add a lot of lift to the transom, drastically changing the handling. He also mentioned that the addition of the plate will require more positive trim at speed. He wasn't opposed to it, but mentioned those potential issues.

Did those who added the plate notice these characteristics?
 

wet hull

Well-Known Member
Joined
Mar 19, 2008
Messages
1,393
Reaction score
1,677
My MMW made a world of difference. Boat rolls over great with full tanks and 2 people. 8 people and full tanks not so much. This is where it changed the game and made the rollover easier and faster. You will not he disappointed.
 

Husqy510

Well-Known Member
Joined
Aug 9, 2011
Messages
602
Reaction score
593
Thanks, so far I haven't read anything negative, but want to make sure I'm informed.
 

02HoWaRd26

Well-Known Member
Joined
Dec 19, 2007
Messages
8,065
Reaction score
16,308
A friend with a lot of experience setting up performance boats mentioned the cavitation plate can add a lot of lift to the transom, drastically changing the handling. He also mentioned that the addition of the plate will require more positive trim at speed. He wasn't opposed to it, but mentioned those potential issues.

Did those who added the plate notice these characteristics?
Yea idk about any of that. The only change i noticed was getting on plane, and that it helped with low speed turns (180°) it helped reduce the blow out of the prop.
 

Motor Boater

Well-Known Member
Joined
Dec 21, 2007
Messages
4,099
Reaction score
2,977
What does the plate look like? I didn’t see it in their website. My 28 Bullett has issues rolling over when it’s loaded down.
 

2FORCEFULL

Well-Known Member
Joined
Jan 26, 2008
Messages
26,835
Reaction score
13,842
Thanks, so far I haven't read anything negative, but want to make sure I'm informed.
I got in this same situation,,, the fix for me was I did a 2'' drive spacer... it made a world of difference, boat handled better all threw the throttle... but the neg. was it lost 2 mph on the top end.... for me it was a great trade because I wasn't after max speed as much as usability
 

2FORCEFULL

Well-Known Member
Joined
Jan 26, 2008
Messages
26,835
Reaction score
13,842
A friend with a lot of experience setting up performance boats mentioned the cavitation plate can add a lot of lift to the transom, drastically changing the handling. He also mentioned that the addition of the plate will require more positive trim at speed. He wasn't opposed to it, but mentioned those potential issues.

Did those who added the plate notice these characteristics?
I agree with your friend... could get wierd at WOT pushing the COG forward....
 

2FORCEFULL

Well-Known Member
Joined
Jan 26, 2008
Messages
26,835
Reaction score
13,842
On this boat,... the only person I personally would talk to is Gene...
 

02HoWaRd26

Well-Known Member
Joined
Dec 19, 2007
Messages
8,065
Reaction score
16,308
What does the plate look like? I didn’t see it in their website. My 28 Bullett has issues rolling over when it’s loaded down.
I can go take a better pic if needed but i screenshot this from another to get you an idea.
665D6942-6A8B-41E0-9440-B301B488DA0A.png
 
Top