trim tab mounting
 

hey guys. i was just wondering about the way i have seen some of the tabs mounted. this is a pic that donzilla put up on another thread (his boat i believe) and i notice the tabs are flat horizontal. does it help the reaction of the tab and what are the most noticeable different driving characteristics over standard mounting? just curious really, thanks all :cool:

I have heard it helps decrease chine walk,, if they are mounted in line w/ the angle they will chine walk with the boat,,, I believe fountain is mounting them this way from the factory..

I have never seen them mounted like that before.

I have seen them mounted this way on other hulls but not this style, and never yet as a factory installation from Fountain. (Although they may be doing this and I just haven't been in the right place at the right time) I do have that particular hull style and no chinewalk with conventionally mounted tabs and get over 80 on a good day. BUT, now I too am curious. Anyone know for sure or is this just a "trial/error" thing? --- Jer

I'm 100% sure it was to help decrease chine walk..

I believe that it also help counter act the thrust of the tabs being lowered unevenly. Of course, if you are tabbing to make a corner, you could take advantage of the directional thrust.

"I'm 100% sure it was to help decrease chine walk.."

Chris232, care to back that statement up ? I am redoing my transom with an extention box, give me some reasons ?

There was a post about this topic a few months back, and I even remember sombody saying this was the way Fountain was mounting them from the factory.

Makes sense,,, if the tabs are on the angle of the transom and it chine walks then the tabs will also just chine walk, if they are mounted straight accross then they add an added dimension to the transom angle.. just what I heard...

Yes, I recall that several Fountains were pictured with the tabs mounted flat as this one that is in the photo. BUT..... I did not recall any clear reasoning for doing it that way. On one hand I think that the tabs mounted flat would help stablize the chine walking senerio, but what would it do for you when you are crusing or leveling out a load ? I think for all out racing they would work well this way, but what about the middle of the road. My arms get sore from the beating I take running flat out... if you know what I mean. (from the wife, not the boat)

There you go now! Maybe the horizontal mounting is the race trick. I'll stick to the Merc. preferred mounting for my "all-round" boating at 80 and below. --- Jer

most of the boats i saw with the tabs mounted this way were either full race boats or high end poker runners. my first thought was that the tab would be on a pretty steep angle before it was really in the water. but after i thought about it a bit longer i realized that the outside edge of the plane is always at the water and as the plane is lowered oncoming water "see's" an increase in plane width as its angle is increased. now this makes sense and the tab might have a variable effect as it is lowered. the lower the tab is the more "width" is avaliable to the running surface. any of that make sense? ;) :cool:

It makes sense but it looks strange:rolleyes:

No Offence :D LOL

Too Old, I think you are correct. They told me to move my tabs in as close as possible to the drives, that way you have more tab in the water to affect the handling. But will you advesly affect the speed ?

Too old that sounds like it makes sense, theres gotta be some reading this board that knows for sure. Greg

Yeah, I mounted my tabs in close to the outdrive but even with the hull "V". It's working well for me and I have totally lost that nasty off plane "bow hunt" or "idle wander" thing. I'll just bet that everyone's situation is going to be a bit different and that there is really no "fitsall" answer to this one. --- Jer

That is my boat,
This causes transom lift therefore less drag in turns and running thus results faster boat. This is how it was explained to me. I had expert rigging from rick at total marine in tuckerton,NJ. Only 1.6 hours on 496HO so got some breakin time to go, But running 69 MPH, on Gps @
4000 rpm this boat rides and turns like it is on rails.
Also 3" high x dimension.
JIm
PS. these Dana tabs are a great value

Check out this months powerboat in the tech. section.. ;) ;) :eureka: :eureka: