Trim Tabs

[fishfeeder]

Howde all wise people,

I have ordered a set of Bennetts Trim tabs and have the installing just about sorted in my head and where everything is going.
Except for a small problem I have with the angle of the transom not being square.
The Trim tabs will need a spacer on the transom to square up the angle so the Trim tab will run square with the hull.... (as clear as mud I know)
Other Seafarer Vagabond / Victory owners must have this same problem as the transoms look to have the same steps so I am guessing the angles are the same aswell.

Can someone give me some pointers as to what material I should use and how to put it on to the transom and how do I work out the angle.

Cheers
Brett

[Chimo]

Hi Brett

These pics show the Lencos as fitted to my Vagabond. You can see the extent of spacer (none) used to fit these which work fine.

Good luck you will wonder how you lived without them.

Cheers
Chimo

[Chimo]

These are probably useful too
C
C

[Micadogs]

Hi Brett, Chimo's pictures are excellent so use them as a point of reference, especially cutting holes through the steps.

In relation to "squaring up with the hull" - if I understand your question correctly you dont need to do this.

You need to have an even space across the bottom of the tab and hull (as shown in Chimo's second post, left hand picture).

The connection at the tab and at the hull can move approx 270 degrees so it wont matter if there is an angle in the transom.

The tabs work by forcing water under the rear of your hull, not under the tab itself (or the boat lifting on the tab). This is why it doesn't have to be square to the hull.

Hopefully this answers your questions - Chimo pictures are excellent for a visual.

I fitted Lenco's to my boat so dont hesitate to ask any further questions.

You will be surprised just how good they are!!!! I still cant believe it!!!

Regards Adam

[odes20]

Yep just installed Lencos 9x9 same as Chimos.

Just fantastic, and yes I agree just put them on like the pics.
No need to square to hull
John

[fishfeeder]

Thanks guys and Chimo those pictures are great and I had found them before while searching Trim Tabs on this forum. I am getting the extra Short Actuator so no need to cut holes in the steps.

The Tab (M120) looks in there installation video and online seem to have the wings pointing down (into the water). So if they are not pointed straight out the back of the boat they will create spray and be under heaps of pressure and cause drag from the water flowing under the hull.

Chimo when you stand at the back of your boat you will notice that the Trim Tabs point out towards the side at an angle, because of the angle of the transom under the boarding steps..... I also notice in your pictures your Tabs wings point up, this is opposite to the Bennetts Tabs.

This is why I asked how do I make a Shim to straighten the tab so its square, So while under way the water will flow straight under the Trim Tab instead of it flowing at an angel.

Hope this now makes more sense

Cheers
Brett

[Chimo]

Brett

I suspect there may be an ever so slight angled flow under the tabs at really slow non planing speeds; while the tab is probably not active or effective I doubt the even if this occurred at planing / higher speeds it would not appear to be an issue as the tabs certainly work IMHO and a few others who also posted on this thread. In the true Qld idium therefore may I suggest "Dont you worry about that!"

Cheers
Chimo

[Smithy]

I'm with Chimo. Don't worry about it. Tabbing a bit on one side moves you off course anyway so tabbing a bit and putting those little wings into play is no biggy as you would have to correct no matter what.

[fishfeeder]

OK, Sounds like maybe I have over thought this matter. It just seemed weird to me that they were at an angle and I like to do things right the first time.

Cheers
Brett

[johncar]

I don't want to add to the confusion but I like to run my tabs at the correct water flow angle and I know that lamost everyone else doesn't worry about it.

You don't have to have them perfect. Just my OCD to have to have thing running at their optimum.

I have fitted 9" x 12" tabs to two seafarers, my Victory and a friends Viking.
Both sets were wedged to run parallel with the water flow.
On those boats I cut two wedges from a white poly material I bought from a plastics supplier at Lytton. (their name escapes me).
Across the wedge it was 25mm at the widest point to nothing across the width of the 12" tab.
I wouldn't say they were absolutely perfect but very close running nice an parallel when just skiming the water.
Now bare in mind that this all changes as you tab down into the water due to the deadrise at the stern, they start to toe outward and become less parallel.

So if you are really fussy you would have a little toe in when fully up going to a little toe out when say about half way extended.

On my latest boat Tournament 2100, I have also fitted wedges to help correct the angle, see below.
These are even more wedged then on my Victory, from 30mm to nothing.





At the end of the day I figure that there will always be a bit of turbulence and spray from the tabs and I know it is not normally a major problem just fitting them straight on the back but i feel better when I see them running nice and inline with the water flow and minimal water spraying around.

just remember too that the water flow behind the boat at cruising speed is not parallel to the boats keel in either axis. It is both being forced inward and upward.
Regardless in what you decide to do your boat will be so much better for it. Tabs are GREAT!

[fishfeeder]

Johncar,

That's what I was getting at and your pictures and details make a lot of sense to me and explain what I was thinking about.

I am thinking seeing that the tabs will only be down maybe 1-2 inchs when activated so working on that amount it shouldn't be that hard to work out the toe in or out......

Did you just use longer screws to attach the Tab and the Spacer to the hull.

Cheers
Brett

[Chimo]

Hi JC and Brett and other AFs

On those boats I cut two wedges from a white poly material I bought from a plastics supplier at Lytton. (their name escapes me).
Across the wedge it was 25mm at the widest point to nothing across the width of the 12" tab.

I would be very careful about hanging a tab that will experience significant forces, depending on the speed and the down angle, on a semi- flexible item like poly material. I doubt this stuff was ever meant to be used this way, it is usually used as spacer material ie I have it under my fuel tank to keep the tank off the frp tank bed and between the motors and the transom.

If one wishes to fit a spacer as JC has done the spacer should IMHO be a solid / metal object ideally stainless steel.

I still don't see the need for a spacer and neither did Lindsay Fry the then owner of Seafarer who fitted my tabs.

Cheers
Chimo

[Danstu]

Hi

Just finished fitting a pair of Bennetts on my Victory. Didnt use any spacer. The hardest part was cutting the holes in the right spot through the boarding steps. If you want to come around and have a look let me know. I am at Albany Creek.

Cheers

Howde all wise people,

I have ordered a set of Bennetts Trim tabs and have the installing just about sorted in my head and where everything is going.
Except for a small problem I have with the angle of the transom not being square.
The Trim tabs will need a spacer on the transom to square up the angle so the Trim tab will run square with the hull.... (as clear as mud I know)
Other Seafarer Vagabond / Victory owners must have this same problem as the transoms look to have the same steps so I am guessing the angles are the same aswell.

Can someone give me some pointers as to what material I should use and how to put it on to the transom and how do I work out the angle.

Cheers
Brett

[Lancair]

Brett, you have a valid point. I understand exactly what youre talking about with the Bennet tabs and not being straight with the hull and the little side strakes on the Bennet Tabs. One of mine is out of alignment due the hull not being 100% square. It DOES have an effect and After seeing the Lenco tabs with only the slight raise on the outside edge or just dead flat, Im going to take mine off and have the side piece removed, leaving only the slightly raised section to the edge. It has a significant effect on my boat. True, putting one tab down will have a steering effect anyway but I can tell the difference between each side on mine. The right tab pulls the boat more right that the left pulls left. Id try to get them straight or just cut off the bit like Im going to do.

Lancair

[fishfeeder]

After looking at the pictures and reading the replies I have decided to install without the spacer. If the tab seems to be running to weird i will make a spacer.

Danstu, I ordered the shorter actuators (rams) so I don't have to cut holes in the steps.

Thanks for the feedback and help.

Cheers
Brett