trim tab placement

[whitly]

where, exactly, do you place the trim tabs on the transom?

[Old'sCool]

As far outboard as possible....

[McGillicuddy]

And flush with the hulls plane at the bottom of the transom -- that sounds odd -- see foto at upper right of this thread from Metan Marine:
http://www.classicseacraft.com/forum...b=5&o=&fpart=1

[waytogo]

As far out as possible and 3/8 -1/2 off the bottom, I believe.Check with tabman on the Hulltruth forum.

[McGillicuddy]

Or check this site out
http://www.bennetttrimtabs.com/online.html

[bigeasy1]

Different tab types,require different mounting and placement methods.
I just finished installing a set of Bennett 12"x12" drop fin tabs.I actually spoke to the folks at Bennett while i installed them.
My tabs required they be mounted with the leading edge flush with the hull bottom,and the trailing(outer) edge,at a negative 5/8".
Other Bennett tabs,like the sport tabs, call for the leading edge to be 1/4"above the hull bottom.
They are pretty easy to install,if you take your time and follow the directions.
They recommend mounting all their tabs as far outboard as possible(about 3"in from the chine).

Here's a couple pictures, of the tabs on my transom in progress.

[FELLOW-SHIP]

Ha Whitley
I see you have the 20 footer. That would dictate the size taps you will need. If you look at the pictures of the i/o and where they placed the tabs that is where you want to place your tabs. Seacrafts are a longitudinal step hull and on the 23 footers that last step outboard is approx 15 inches thus a 12 x 12 is really about your max for the boat. Adding drop fins traps more water under the tab and increases the lifting potential for heaver weights on the stern like a stern drive of twin outboards. On my 23 with one engine the 12 x 12 with no drop fins work fine. I could probably even go with the M 120 which are a 12 x 10 and a 1 inch drop fin.
You will have to measure the last longitudinal step on your boat hull first. As our Bennett web sigh says you really want to measure in approx 3 inches from the end of your transom and get your width from there to where the next step starts going down again. That will give you your span for your trim tabs I would go with 12 inch chord to give you a bigger bite on the water. With out measurements my guess you will need the M 120 for you 20 footer or maybe a 12 x 9 tab.

Here is another page for our sizing guidelines
http://www.bennetttrimtabs.com/size1.htm

You can contact me at Bennett just ask for Ken McGovern after you measure that last step if you would like to talk.

Here is a picture of my transom as well.



FellowShip

Just for the Grins

[Islandtrader]

I just finished installing a set of Bennett 12"x12" drop fin tabs.

For information only...Why did you install that type of trim tab? I will put tabs on the 21 and I am just gathering facts. Transom looks good.

[Old'sCool]

I put those on my last boat (22' Whaler). They have more surface area with the "fin" and were perfect!! Tom at Bennett offers the definition of service! He's a BIG help.

[bigeasy1]

Island,these 12x12 drop fin tabs were the size recommended to me by Tom at Bennett Marine.
The 3" drop keeps more water under the tab,increasing lift.I think Ken(fellowship) can explain it to you much better than I.

I'm only running a 250hp 350 I/O,and will have a Yamaha kicker on the back,along with four downriggers,with 12lb weights,so with the extra weight i figure the more lift the better.

Hopefully,i can splash this thing by the end of summer.Engine is in,new transoms in,decks done,major glass work is done,now have to glass the rear cap back on,do the wiring, install the arch and rocket launchers,electronics, paint etc. etc.

As for Bennett Marine,i can't say enough about how good their customer service is.They are great.I think i may have talked to ken,about a week ago,explaining that the pump cover was cracked,and that i also needed a new hydraulic fitting.
A few days later,they arrived at my house at no charge.Thanks Ken.