Trim Tab control

[bj218]

I recently bought a 92 218 presueder, 454/carb. Long time boater, first time for trim tabs. Upon plain, tabs up, 35mph, I stab it and the port side dips down big time, maybe 15 dgrees, scares the heck out of my wife, if I back out of it real fast sarboard goes down, I cant believe this is torque, 330 hp. I find I have to run with port side trim down about 3 notches most of the time to keep it level. At WOT, calm water with no wind should I be able to run with tabs all the up, do I get my best top end this way? This boat has become a real challange to operate correctly, is this the norm or is this driver error. Thanks y'all

 

[Big Dave]

What is the rest of the setup? what prop, size pitch?
Should be able to set the tabs @ 1/2 deg up and leave them for most of the time

does the steering have a lot of play? p/s working ok?

 

[bj218]

Thanks Big Dave, my stering seems fine to me, no play and good response. My prop is a Merc. Vengeance 48 16318 21P 3 blade. When you say 1/2 a degrees up, how do I know how much that is, my indicator is a set of parallel red lights broken up into small squares, maybe 6 or 8 positions from tabs down to tabs up.

 

[Big Dave]

Use a strait edge and mark on the gauge when the tabs are level with the bottom of the boat

 

[daren34]

i can't imagine running a vengence on that boat
no were near enough prop
to small of diameter

what kind of rpm are you getting out of it?

try a few different props see how much it changes

try a mirage 21 pitch
(i must soumd like a salesman, but i really like this prop)

maybe a 4blade bravo1

that boat is going to be stern heavy and you need a bigger prop to carry the boat the way it should

daren

 

[daren34]

on most mates trim makes a huge difference

when you come up on plane trim up and see if that doesn't correct the list instead of having to use the trim tabs so much

this is were a larger diameter prop will help

good luck daren

seems like even my eluder will ride down with watever side is heavier
until you raise the trim then it levels itself out

may just be more pronounced on a larger boat

 

[Big Dave]

I tried a vengance 21 on the diplomat after I changed to the v8, and the boat would porpoise in the lightes chop, and would blow out on turns easily with the trim up any at all...most of the time I had to make sure someone was sitting in the bow to stop the porpoising, and there was very little change from trim all the way down to all the way up
the Mach 4 blades hold the boat much higher out of the water at all speeds, planes faster, trim much more responsive, hgher top speed
I am sure there are other props that work as good, but I havent found anyone to trade around with to try a bunch of props.