trim tabs
 

Just bought a 21 apache scout but it needs tabs. Looking for some insight on what size and what to buy.

why do you say it needs tabs.

The boat has a merc 250 on it with an extension box. At 4200 rpm im doing about 60 but i start chime walking. I dont feel safe trying to get the rest of the rpms out of it.

:)

You don't need tabs, you need a different prop or less trim. What speed is it chiNe walking at?

22" tabs would bury the bow under water if you ran them down at any kind of speed- instant submarine. You wouldn't want anything over 8" to 10" on something that small.

lenco electric tabs, i put them on my scarab 22, work great , dont need all that extra weight and small boats dont really dont need trim tabs all the time

the chine walk is inherent with that boat. i had the same one with a 300 merc and it sat on a cmc jack plate. no matter what i did to try to solve the issue of chine walking, nothing worked. the only solution was to grab yur ballz and drive thru it. once thru the dnace it would run just about 90. but what an ass pain to get there.
you may want to bolt on a 2.5 280 with no box and call it a day.

to drive through it you need to counter steer real quik and fast if it walks a lot. hdy steering will help if not fix it. monstaaa did not say if he had full hyd steering, so maybe he can add to this. I GET IT IN MY BOAT FROM 76 TO 83 RIGHT NOW, BUT WILL BE GOING TO FULL HDY STEERING, I have add on now, well didf be for it got stolen last spring hope to be out there in 2 months:grinser010:. once you start whipping the wheel back and forth you can't stop its a pain but it works for me. art

I will found out how it runs in 2 weeks.............. :) I spoke with a member that had one with 280 tabs and he recomended going longer than the 280s. I do agree that buring the tabs would not be good. I think the idea for the longer ones would to increas your running lenght.
Jr.

I do have hyd steering but im still getting mixed signals from everyone. I would love some more input on wether i need tabs or not. I love the boat and i want to get every thing i can get out of it. I have ran it it at 4200 rpm at about 62 mph but i want more. OSO please help me out. Big shout out uo j-bonz for helping me out with everything.

I agree, I would still like some facts on going eithee way with the tabs. Ido know most agree we still have at least 1000 rpm's out of the engine to go. 2 weeks nut and then we will find out more.........
Thanks for all thats helped out my good friend, Itspeanut.
Jr.

280's used to have a warning cast right into the top of them...

"Do not use on boats under 24' "

You can't diagnose chine walk unless you understand why it's happening. There are many reasons, including exceeding the design limitations of the hull (speed), changes in balance (weight distribution) excessive trim, improper props, etc. Chine walk occurs when the hull loses it's ability to stay up (lift) and it falls, causing the boat to oscillate on its outside contact surfaces (hard chine). Tabs are just going to push the bow down, slowing the boat and probably presenting a dangerous ride attitude at max speed.

If I had to guess, you either have too much motor setback, too much prop height (x-dimension) or a prop with too much stern lift.

There was some posting a while back on brackets and setback on this hull. Supposedly the long brackets can cause problems. My recollection isn't that good. You'll have to plow thru some searches. Try posting in the Apache section- or maybe PM'ing Eric Froberg.

You could also have air in your steering. The only way to tell is to bleed it very thoroughly. it may feel firm when you tug on it but at hard load, it could be squishy.

the steering was hydraulic as well on my unit. ended up swaping the big 3.o for a 2.5 . which is why i suggested it.came out to a 4 1/5 inch setback, plus the 4 built into the 2.5 shorty midsection. the weight is an issue. high c.g of that big 3.0 power head only intenseifies the issue once it starts. plus the set back. i would hope not something like a gill bracket but more like the stainlessmarine box6,8,or 12 inch kind.
more than likely the bottom has issues, starting the whole cycle of events for that hull.
had similiar issues with a 30 superboat, 300 x's 4 inch cmc jackplates. ran 92 mph. getting thru the 75/76-8 barrier was hell. th ebottom did have issues as it too ended up being trued. however the same boat same year same size and weight, just used the 2.5's . different beast..

ya dont see to many 22 allisons with 300's now do ya.
ever see or better yet run one. and watch or feel what happens right at that point,? yup.

f that.

Thanks for replying. In two weeks I will be down to give it run. Dont worry, live jackets and lanyards will be worn.............. :)

ItsPeanut,
Well, 2days to go and I will be on a flight........... Cant wait to check out the new rig and give it a spin,,,,,,,,,,,,,
Jr

Ohhh my liver.....................