Dumb Question: What is trim tab?

I have run a 2003 60HP Merc Tiller (4-stroke) and I have no idea what the trim tab is and where it can be found? Maybe I do, but never knew what is was called. Anyone have a picture or can describe for me?

Thanks!

[JOE WALLEYE]

The trim tab you are looking for is the small fin behind the prop. It extends down from the flat plate above the prop.

by making small adjustments on the angle of the trim tab you deflect some of the thrust from the prop to the side to over come motor torque.

[TheRattler]

What happens if your motor doesnt havent one of these fins?

[Hawker]

Originally Posted by unlogged nc

I have run a 2003 60HP Merc Tiller (4-stroke) and I have no idea what the trim tab is and where it can be found? Maybe I do, but never knew what is was called. Anyone have a picture or can describe for me?

Thanks!

Here is one example/explanation, though maybe not what your looking for: (http://www.boatus.com/boattech/articles/trim-tabs.asp)

In your case, you are likely referring to:
Trim Tab

The prop spins in one direction causing the motor pull to one side, making steering tiring. On most motors, particularly the big ones, there is a little fin that hangs down behind the prop to counteract that pulling while the boat is in motion. By turning the fin to one side or the other, the twisting of the motor is offset.

[staylor]

If you're running a tiller motor and at cruising speed or top speed the tiller is being pulled strongly to one side, then you need to adjust the tab. For tiller motors, start by turning the back edge of the tab as viewed from the rear all the way to the right. This should cut the torque down- and if the torque is now in the opposite direction to before, then move the tab back a bit until the tiller needs roughly the same force to move it left or right at higher speeds. The torque felt on the handle of a tiller motor also changes significantly with the trim position the motor is in. Thus, on boats with power trim and steering wheels it is fairly common to have the tab replaced with a plain flat plate, since these boats can have the torque change a lot as the boat changes speed and trim position for best performance.

If you have a tiller rig and find that your need even more correction than available from moving the tab all the way to the right( as noted above), then you need to add a second trim tab to the lower unit skeg. For some reason the Mercs I have run over the past 25 years in the 15-25 hp range all ended up steering the best with the tab full right and a skeg tab added that is around 2 inches in length. The skeg tabs can be bought thru the various catalogs- like Bass Pro or Cabelas and simply cut to length and pop riveted to the skeg- they are usually called a "torque tab" in the catalogs.
Doug

[REW]

A couple of different definitions.
An anti torque steering tab is the small tab that is located on the lower unit of the motor on the underside of the cavitation plate above the propeller to combat steering torque from the spinning propeller.

The classic trim tab is a tab that is located on each side of the transom of the boats hull at the water line and is used to level the boat and to adjust the attitude of the boat when underway.

There are about three fairly well known manufacturers of trim tabs.
1. Bennett tabs that are electric hydraulic actuated and typically have independent adjustments from side to side of the boat.

2. Lenco tabs that are all electric in nature and use an electric motor to change each trim tab attitude.

3. Nauticus tabs are spring loaded gas shock in design and deploy automatically and retract automatically when underway.

Good luck
REW

[REW]

http://www.nauticusinc.com/smart_tabs.htm

http://www.bennetttrimtabs.com/

http://www.lencomarine.com/trimtabs.html

[TheRattler]

Originally Posted by REW

A couple of different definitions.
An anti torque steering tab is the small tab that is located on the lower unit of the motor on the underside of the cavitation plate above the propeller to combat steering torque from the spinning propeller.

The classic trim tab is a tab that is located on each side of the transom of the boats hull at the water line and is used to level the boat and to adjust the attitude of the boat when underway.

There are about three fairly well known manufacturers of trim tabs.
1. Bennett tabs that are electric hydraulic actuated and typically have independent adjustments from side to side of the boat.

2. Lenco tabs that are all electric in nature and use an electric motor to change each trim tab attitude.

3. Nauticus tabs are spring loaded gas shock in design and deploy automatically and retract automatically when underway.

Good luck
REW

Is there any disadvantage of using the Nauticus gas loaded tabs, compared to the electric ones? Beside getting more precise control.

[REW]

Rattler,
The nauticus are a good choice for boaters who want most of the benefits of a trim tab without the big bill of installing a motor driven trim tab.

You get the advantage of quick on plane, no now up on planing out, shock absorber action when crossing waves and boat wakes.

But, you do not have the advantage of independent tab adjustment.
You do not have the advantage of fine tuning of one tab or the other.

So, if you generally run level from side to side, but just want to keep the nose of the boat down, help with boat porpoising issues, and or if you want to use the trolling plate option - slow down the boat - then the Nauticus tabs will work well for you.

If you find that you need to do slight tweaks on a boats trim from side to side. If you find that you need to dial in the boats planing attitude exactly for small load and or trim changes, then you will be happier with the fully independent adjustable electric or hydraulic trim tabs.

I think that the vast majority of boaters would be more than satisfied with the performance of the Nauticus tabs. But there certainly unique boats and boating requirements that will need the fully independent trim tabs.

Good luck
REW