Bigger trim tabs

[stephens013]

Increased the size of the trim tabs by 30% and added lower fins. Now I have to give it a go on the ICW. :grin:

 

[docofthebay]

I upped mine too last month. I added 50% more area and if I can ever get the boatyard to drop my boat in ( thats a whole 'nuther frustrating story) I'll find out how well that change works.

 

[Tabman]

Sounds good guys! I am really looking forward to hearing what you think once you get a chance to run with the new Tabs!

Tom McGow
Bennett Marine

 

[skillz48047]

What did the upgraded tabs cost if u dont mind me asking?
do they work with the existing actuator

 

[docofthebay]

Got out with mine yesterday and today and they worked awesome! The nose of the boat rides a good foot and half lower and picked up almost one mph for the same rpm. Tabman advised me on this setup. All 4 actuators are working off the one pump. I put 2 additional 12x12 tabs to the inboard of the prop tunnels in addition to the existing 12x24 tabs outboard of the tunnels and just plumbed them into the line to the existing tabs. . I'll try and post a picture tomorrow. Luv it!!!

 

[Tabman]

Doc,

If you post some pictures, may I please copy them and your results to post on our Facebook page? We get quite a few questions about Trim Tabs and prop tunnels and it would be really helpful.

I am delighted to hear the results, it sure sounds like is project will pay for itself quickly!

Tom
Bennett Marine

 

[stephens013]

Just back from a run with the new tabs. Results were great; lowered the nose a good foot at all respective cruse power settings. Handling was much the same.
I used the same single cylinder set up that is on my boat. Bennett recommends a 30 X12 tab increase for my boat with a single cylinder so that is basically what I ended up with.
The Bennett technicians I talked to were divided on whether to put tabs above the tunnels. One guy says that is a great idea; call back a week later and mention it and someone else is talking things getting ripped off the transom. I elected not to go with tabs over the tunnel route. One thing they were in agreement on was not to go more than a 12 inch span on the tabs. Anything over a 12 inch span causes way to much drag when fully deployed. Think mine are about 12 1/2. I purchased the drop down fins though West Marine. Bennett will give you the part number.
The Bennett folks will sell the new tabs measuring 30 X 12 through West Marine for $210 each. No actuators or anything. The Bennett drop down fins were $16.00. I got a metal working friend to cut the blanks and put some strengthening angles on some stainless stock. That was just over $135. Other than that it was just the #8 nuts and bolts to tie it all together.

 

[skillz48047]

i am a bit confused......
is it just a bigger tab that your using or did you add a whole other tab/actuator setup on each side to make a total of 4 tab/actuators?
i would love to get some of the specifics from tabman, as far as what parts this mod takes......i would love to get my nose down and this whole setup seems like it would save on gas too.......
any specifics would be greatly appreciated!!!!

 

[crowder]

I agree more pictures would be greatly appreciated. My Bennet tabs are curved over by the previous owner and dont do a whole lot to bring the nose down. I have been thinking of increasing the size an using the fins as well.

 

[stephens013]

As I said; mine is just an add on to the existing single cylinder tab set up. The gentleman from Alabama added a whole new set up over his tunnels; Tabs cylinders and all. Then plumbed the hydraulics in to the existing actuator pump.
Here are a few more photos of what I did to my existing tabs. Might make it a tad clearer. Just know that it works.

 

[docofthebay]

My original idea was to enlarge the existing tabs like Stephens013 did. However, my existing tabs already took up the full width of the hull outside of the prop tunnel, so that was not an option. So then I thought about adding the two 12 inch ones inboard the prop tunnels. The available space was 14 inches per side. I got the 2 tabs from flounder pounder marine for $65 total. Tabman advised me that the original pump would do 4 actuators so 2 new actuators from West Marine, and several inexpensive brass fittings from Lowes let me plumb the new tabs into the original lines. Installed new port side into old port side and starboard to starboard.
I will attempt to post a couple of pictures below but unfortunately they usually end up very small in size. If so I'll figure out a way to post a bigger size.

,

 

[skillz48047]

Thanks alot
i understand now
i just may have to do that as well!!
great idea!

 

[stephens013]

Very nice. Good score from Flounder Pounder.

 

[dpmulvey]

Here is my mod. Work like a champ. They were 22*9. They are now 22*18. They take some getting used to at the start of every season. The boat is very sensitive to input. I've cut my cruise from 3650 - 3800 (sea dependent) to 3250 - 3400. No loss in speed. She runs flat. Total cost to a local welder was $375 for fabrication and welding to current tabs. The pictures give you an idea of just how much larger they are.

The surface area is about double the size. Extending them aft completely changed the pivot point for lift.

I'm very pleased.

 

[pjv911]

How thick or what gauge does the stainless need to be?

 

[Getaway]

I used 1/8" thick stainless material.

I did the same thing to my 268. Yes, it makes a difference. Just wish I had made the extensions bigger.

 

[stephens013]

Been asked what gauge SS I used. Tell you the truth I'm not sure. I called Bennett; asked them what they used and got the same stuff.

 

[waynepj3]

My original idea was to enlarge the existing tabs like Stephens013 did. However, my existing tabs already took up the full width of the hull outside of the prop tunnel, so that was not an option. So then I thought about adding the two 12 inch ones inboard the prop tunnels. The available space was 14 inches per side. I got the 2 tabs from flounder pounder marine for $65 total. Tabman advised me that the original pump would do 4 actuators so 2 new actuators from West Marine, and several inexpensive brass fittings from Lowes let me plumb the new tabs into the original lines. Installed new port side into old port side and starboard to starboard.
I will attempt to post a couple of pictures below but unfortunately they usually end up very small in size. If so I'll figure out a way to post a bigger size.

,

Did you notice a significant difference in how the boat performs? Biggest pet peeve with cruisers is lack of visibility due to the bow running high at low planing speeds...if there was a solve for this it would make this style of boat more attractive.

 

[b_arrington]

Did you notice a significant difference in how the boat performs? Biggest pet peeve with cruisers is lack of visibility due to the bow running high at low planing speeds...if there was a solve for this it would make this style of boat more attractive.

This guy hasn't been around since 2015. You likely won't get a reply from him.

 

[Monty848]

Waynepj3,
Unfortunately, I believe “Tabman” passed away last year, he was from Bennett and had fabulous information on the subject. I did get some guidance on our boat, ‘89 340 sundancer, T340hp Merc 7.4w/BW Vdrives. I replaced 9 x 30 angle cut, stock tabs with 30 x 12 drop fin tabs when I purchased the boat, so I don’t have “before” data. Our boat consistently does 21-23 KTS @ 2800-3000rpm on “relatively” flat water. As I’m on Buzzards Bay, Ma, our “flat” conditions always have a bit of something. This is with the bow planted flat. Pictures below