410 DA Trim Tabs-for Tabman

mistercomputerman

Well-Known Member
Jan 6, 2008
4,321
Virginia Beach, VA
Boat Info
410 Sundancer - 2001
Engines
Twin 8.1L Mercruisers - 2009
Tom

Enclosed is a photo of the transom of my 2001 410 DA showing the trim tabs. Your comments, thoughts and recommendations are appreciated.

tabman01.jpg
 
Tabman will be sure to provide you with some expert technical advise. But, until then, might I suggest that your 'Next' set of motors be diesel?!?!?!?
 
Well, well, well....looky who came out of the woodwork, Mr. osd9 hisself, in person...

I might have known that I couldn't start a thread without comments from the NCPG. (Northern Contingent Peanut Gallery)
 
Thanks. I remember reading that post. Tabman had asked me to start a new thread about my questions so everyone can see.
 
Don't know if Tom will see your post here, or not. You might want to put your post in his Bennett-specific forum.
 
Thanks

I didn't scroll far enough down the page before I started the thread to find the Bennett Forum.
Now I have to figure out if I can move it or a moderator has to move it.
 
Rick,

Not to highjack the thread, but looks like your bottom is getting ready for some refit. I think I'll to do the same next year. Did you soda blasted?
 
That was a couple of years ago. Sand blasted, fixed any imperfections, 4 coats of Interlux barrier and 4 coats of ablative bottom paint.

Haven't had to do squat for the past few years other than a little paint.

I went to the yard this year in April for paint, a transducer and some propscan work and have been boating ever since.
 
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I'm confused. After realizing a 50% gain in efficiency, while gaining speed and finally having a boat that can get out of it's own way, you want to add more tabs?
 
Rick,

There is a great thread on larger Trim Tabs here http://clubsearay.com/showthread.php/50001-Bigger-trim-tabs as you will see some guys have fabricated larger tabs, and or added drop fins. I really like the addition of separate inboard Tabs like docofthebay did.



Since the top of your propeller pockets are quite flat mounting Tabs over them is another option.

Tom
Bennett Marine

Hi Tom

So, are we saying that is the best solution?
 
Not really, the goal is to increase surface area and get more lift for less drag. Yes I said less drag! That is because the larger surface area will need to be deflected less to generate the same lift as a smaller area deflected to a greater angle.

To do this on your boat there are several approaches. If you read the thread I linked you can see how the guys increased their Trim Tabs surface area and or added more Tabs.

On your boat we can see that the Trim Tabs that are installed do not make full use of the available mounting area. The could run the entire length of the red arrow drawn over it. It would be 12" in chord (fore to aft) and whatever span (side to side) that best fills the area. Also it would benefit from having 3" drop fins on either side to capture water pressure that is lost out the sides and convert that into additional lift.

Next step would be to see if you can fit Trim Tabs in the other two areas indicated by the other arrows.

If you opted to mount Tabs over the tunnels I would not recommend drop fins on those ones as the turbulent flow from the pocket can cause them to vibrate. Using a stock "flat" Tab is preferred.

So we would need to know the dimensions available to us in order to pick the best.

It could also be done in steps, such as installing the larger outer Tabs first and seeing how that helps, or teeing in the additional Tabs first.

Like all things on boats there is usually not one "best" answer!

tabman01.jpg


Tom
Bennett Marine
 
I am with you so far. Do you sell the larger tabs with the 3" drop or is that a fabricated thing? Since I am in the water, I'll have to work on getting measurements without getting too cold or wet.
 
I am with you so far. Do you sell the larger tabs with the 3" drop or is that a fabricated thing? Since I am in the water, I'll have to work on getting measurements without getting too cold or wet.

Yes, Trim Tabs with the drop fins built into them are available. They are also available as add ons for existing flat Tabs.

Tom
Bennett Marine
 
OK, thanks.

Do I want to add to the existing tabs or put new tabs on?

Or, do I measure first?


Parts book tells me:
18 566059 TRIM TAB, ASSY 12X24 W/ZINC 400EC271452 TRIM TAB, HYD CYLINDER ONLY479972 TRIM TAB, HYD TUBING​
671875 TRIM TAB, HPU KIT W/ACCY'S
 
I would measure first and get an idea about how much larger you could make the existing Tabs, as well as how big any additional Trim Tabs could be before pulling the trigger.

Tom
Bennett Marine
 

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