Bennett Trim Tabs Advice

[windknotnc]

I have an opportunity to get a set of Bennett tabs at a good price for the 21SE. The span is 18" and the chord is 12". These are bigger tabs than you usually see on this size boat. Question one, is there any reason to not use these due to the size? (I have the space to mount them) Question two, will the hole drilled for the hydraulic line be above the waterline and inside the back boxes?

 

[DaleH]

Bigger is always better! You'll get better performance with less deployment of the tabs, thus not losing as much fuel efficiency as a result (all tabs create 'drag' to work ...).

Yes, the hole is above the waterline, but not sure where it will exit into you hull. The std Bennett actuator is almost 14" long, but at an angle, and depending on the hull, I'd bet they enter the hull a good 5+" above the static waterline (I bedded my actuator tops with 3M 5200).

 

[windknotnc]

Thanks Dale, is the retracted actuator 14"? Does anyone know where the actuator is attached on a 12" chord tab, on the back edge, 1" from edge etc...

 

[Megabyte]

Calling Tabman... Calling Tabman...

 

[Tabman]

Thanks Dale, is the retracted actuator 14"? Does anyone know where the actuator is attached on a 12" chord tab, on the back edge, 1" from edge etc...

The standard actuator is 13-3/4" total length and is mounted 8-5/8" out from the transom. The trailing edge of a 12" chord Trim Tab is 5/8" above the bottom of the hull.

We make an an actuator that is 2" shorter as well as we can modify the standard actuators to be 1" shorter. If any of these shorter actuators would be helpful with your installation let me know.

Tom McGow
Bennett Marine

 

[Megabyte]

Customer service... doesn't get much better than that. 8)

 

[DaleH]

Customer service... doesn't get much better than that. 8)

Yeah, except his question wasn't answered :roll: , haha!

His specific question was ... "where?" on the 12" chord place is the actuator mounted? Is it way out on the back, or is it located on a welded 'tab' 8-5/8" back (akin to the 9" plane position). If all the way back, then he'd need to factor in that the actuator is mounted 11-5/8" back from the hull, no?

You see ... he's trying to determine the mounting height ABOVE the bottom of the hull ... for the actuator top position ... to figure out where he's drilling through on his hull.

 

[windknotnc]

That is awesome service...I have purchased the tabs and will be doing the install in a couple weeks

 

[Tabman]

Customer service... doesn't get much better than that. 8)

Yeah, except his question wasn't answered :roll: , haha!

His specific question was ... "where?" on the 12" chord place is the actuator mounted? Is it way out on the back, or is it located on a welded 'tab' 8-5/8" back (akin to the 9" plane position). If all the way back, then he'd need to factor in that the actuator is mounted 11-5/8" back from the hull, no?

You see ... he's trying to determine the mounting height ABOVE the bottom of the hull ... for the actuator top position ... to figure out where he's drilling through on his hull.

Um, I thought I answered that The actuator is mounted 8-5/8" back from the transom on a 12" chord Trim Tab (as per the illustration). Yes it is on an angle piece that is riveted to the Trim Tab that distance out. I think I could have been clearer about that.

The 8-5/8" distance from the transom for the mounting point is the same on all our standard Trim Tabs (with the exception of the M80 and M120 kits which are 7-5/8").

windknotnc can use the dimensions in the drawing for the standard actuator, the 8-5/8" from the transom and the 5/8" negative angle to determine where the actuator will land on the transom. I often make a little cardboard mockup to see where the actuator will end up on the transom.

I hope this is a bit more clear.

Tom
Bennett Marine

 

[DaleH]

The actuator is mounted 8-5/8" back from the transom on a 12" chord Trim Tab (as per the illustration). Yes it is on an angle piece that is riveted to the Trim Tab that distance out. I think I could have been clearer about that.

Thanks Tom, it wasn't clear to me, so I just wanted to be sure. Cheers !

 

[windknotnc]

Well I have started this install and have a problem. I have followed Tabmans instructions and the top of the actuator is just above the floor level but the hole to connect the hydraulic line will fall below the floor not inside the jump seat where I can get to it. I guess I could run the hose through the transom and not use the 2 1/2" copper pipe, connect it to the actuator and fish it out to the pump. What would happen if I mounted the tab 1" higher up the transom from the bottom of the hull? I think I could get it really close but I am afraid the hole is just going to be right on the floor either above or below. Any ideas?

 

[Megabyte]

I had a similar issue with the install on my 2520.
My solution was to run the hydraulic line a couple inches up the outside of the transom, and enter through a hole covered by a clamshell.
That is how my old Boat Leveler tabs were mounted, and for the same reason.

I know that Tabman has solved this issue before for others.
Hopefully Tom will pop in and give you your options.

 

[DaleH]

Definitely contact Bennett as I'm sure they'd swap out for longer actuators.

 

[windknotnc]

Tabs are installed and functioning perfectly.

 

[DaleH]

Tabs are installed and functioning perfectly.

Nice !

 

[Megabyte]

Tabs are installed and functioning perfectly.

What did you do to overcome the length issue?

 

[windknotnc]

When I drilled the hole I could angle it a little bit up and the hole came up at floor level inside the boxes in the back. Seemed to work great. I sealed with 5200 and don't think I will have any problems.