Lenco Trim Tabs

Da Nag · Posted: Sat Jul 24, 2004 12:09 pm Post subject: Lenco Trim Tabs

I hate to post a negative review, but I know many folks make decisions based on what they read here. If any of you have Lencos and are satisfied with them, feel free to chime in here.

After having used the Lencos for a while, and talking with TyBoo Mike and Mark (2nd Byte) about them, I'm sorry to say none of us are as pleased with them as previous models. Both Mark and I had TrimMasters before (Mark on his 22, me on my 19), TyBoo had the Bennet M80's.

The main problem - they don't have anywhere near the lift that the other manufacturer's models have.

'Tis a shame - I really like the design better. Not having to deal with hydraulics is nice, and the instantaneous response from the screw jacks is a plus. Also, the controls with the integrated position indicators are pretty slick. Still, if'n they don't adjust the boat as they should, all that goes out the window. Both Mike and I routinely run the boat with one side all the way down just to get proper lateral trim.

I've not given up on them yet, but none of the mods I have in mind are ideal. First thing I'm going to try - moving the arm farther forward on the tab bottom, closer to the hinge. In the stock configuration, Lenco places them as far aft on the tab as possible, which gives the least amount of travel possible for the length of the screw jack.

If that doesn't work, I'll look into having the turned-up edges turned down - this would generate a little more lift, and is how both Bennett and TrimMaster build their tabs.

If none of the above proves satisfactory, I'll probably have some extensions fabbed up and bolt them on.

More details as they come, but for now, I'd suggest those of you thinking about tabs consider going with the known good tab configurations - Bennett and TrimMaster.

Larry H · Posted: Sat Jul 24, 2004 12:42 pm Post subject:

Bill,

Could you tell us the size of the tab itself? Maybe they are too small or short in the for n aft dimension.

Da Nag · Posted: Sat Jul 24, 2004 12:59 pm Post subject:

Sorry - should have specified.

The Lencos are 9x12 - 12" being the length. The TrimMasters were 12x9 - same area, but wider and shorter.

Actually, the Lenco's taper to the rear. Mark mentioned in an email to me that he figured that was responsible for a reduction of about 12 square inches.

Not sure what size Mike has on the 25 - when he gets back from vacation, he'll probably chime in.

Here's a pic of the Bennetts on TyBoo 22 - you can see that the ram mounts further back than the Lencos. Same with the TrimMasters - here's a pic from my 19 install.

I'm not sure if there is any travel difference between the three manufacturer's rams that would make up for the differences in attachment locations.

Almas Only · Posted: Sun Jul 25, 2004 7:10 am Post subject:

I have Lencos on a CD22, but don't have the problems you're describing. Would like for you to post some close up photos of the installation (top, rear, bottom and side views) while out of the water with the tabs fully lowered, and of your boat at rest in the water, loaded and ready to go, with you at the helm. Just how much of an imbalance are you trying to correct for, and at what speeds? Maybe I'm not having do do as much correction as you, or am doing so at higher speeds, but ...

Da Nag · Posted: Sun Jul 25, 2004 10:43 am Post subject:

Here's a link to the only photo I've got - can't post more for a while, Da Nag is two states away. I do recall that fully retracted, they were where I expected them to be - raised just a hair above the bottom of the hull. I'm confident there's no install problem - Les has been doing trim tab installs on C-Dory's for years.

A typical load that requires full tab extension to port - full starboard fuel, half port fuel, 3/4 water tank, one adult seated to port. Any more water or fuel, or adding a third adult and I can't correct laterally. With this load, the boat sits pretty much level with nobody aboard.

There's no problem fore/aft, now that I have the Permatrim hydrofoil on. Prior to adding it, I couldn't quite get the bow down far enough with full tanks at lower speeds. On my 19 with TrimMasters, there was no need for a hydrofoil, and it was a more stern-heavy boat.

Also, my kicker is to port, but it's a Honda Classic 8 - pretty light.

Still - glad to hear they are working out for you. Do you have a kicker, and if so, where's it mounted? What's your typical load, and how much tab do you need to correct laterally?

TyBoo · Posted: Sun Jul 25, 2004 6:12 pm Post subject:

Ditto on the Lenco's, Bill. Not enough travel in the actuator. The TyBoo25 has 12 x 12 tabs. They do not taper to narrower like yours do, but the rear corners are bent upward just a hair. The TyBoo22 had Bennett M120 Sport Tabs (12 x 10). That was way more tab than the 22 ever used, but the Lencos on the 25 are inadequate. If I go bigger in either direction, I will need a bracket for the kicker which I do not want.

I already made some 1/2" spacers to go between the tab and the actuator mount, which pushes the tab deeper into the water. That helped quite a bit, but I still find I need more at times. The next plan is to move the actuator mount on the tab back closer to the hinge, giving more travel to the tab. That option is limited by the diameter of the actuator at the top touching the transom when fully down. To help that, maybe I'll take the spacers and put them between the transom and the top mount, which will also be a geometrical plus. But if I have to go to all that trouble, I might just put my original Bennett hydraulic pump and actuators on in place of the stupid Lenco screw jacks.

In my case, though, one big plus with the Lencos is not needing the expensive position indicator. The tab on the side with the most people is always full down, and the other one is constantly being adjusted because the people won't stay still.

Almas Only · Posted: Mon Jul 26, 2004 6:13 am Post subject:

Hey, Da Nag. Go to the Photos section for Trim Tabs, and take a close look at the tabs and installation on Da Nag, and Alma'a Only. Looks to me like our Lenco's are different units, entirely. Note the height of the top mounts. Those on Alma's Only are considerably higher, and the cylinders might be a little different, too. What do you think?

DaveS · Posted: Mon Jul 26, 2004 4:56 pm Post subject:

SeaSpray · Posted: Mon Jul 26, 2004 10:44 pm Post subject:

Hi Bill,
Sorry to hear the Lenco tabs are no working out. Especially since I will be getting the same ones on my boat. Should I reconsider this option? ( If it is not too late).

I will probably be mostly cruising with the 2 of us and plenty of gear. We usually take too much stuff. I am also planning on hauling a kayak and the 35lb inflatable.

Since I don't have any real experience (yet) cruising CD,s or trim tabs I have to rely on Les and the C-Dory group.

Thanks,
Steve

Mighty Bite · Posted: Wed Jul 28, 2004 2:48 am Post subject:

I'm going to run the Lenco's as is this year and if more lateral correction is needed figure a way to configure/reconfigure a fix. The tapering to the rear of the tab is a big minus (as it makes the 9'' x 12'" stated size of the tabs simply a misstatement of fact). Not turning the edges down to better contain the water flow on the tabs is another minus.

I don't know if anyone has had a serious conversation with Lenco regarding a fix on the above but it would be interesting to do so. I would like to know why they do the taper and why they don't turn the edges down. Seems simple.............or am I missing something.

As an initial compensation I did install the Permatrim hydrofoil as Bill did and I really do like it. Took it out in the heavy weather to day and the CD handles great with it and it is far superior in every way to previous hydrofoils I've used such as the Sting Ray and
SE300.

Sawdust · Posted: Wed Jul 28, 2004 12:06 pm Post subject:

Hi Mark,

The tapered Lencos work great on lots of 22 CD's. The more wetted area you have, the more drag. As I'm sure you remember, the original designers of our CD's didn't want tabs period! And If you have ever been seriously down-swell in a following sea with the tabs down -- no doubt why. Makes sense to keep them as small as possible if they will do what they are designed to do.

I really like trim tabs on the 22, and it would be a different boat without them -- but when you use them for lateral trim to correct improper boat loading, you are significantly reducing hull efficiency and increasing fuel consumption. And of course when you trim down into a chop to get a better ride you do the same thing. Gotta pay one way or the other, eh? TyBoo22 is an excellent example of the right way to do it! The outboard bracket/tab combination works great.

All of these floating gadgets are compromises, eh? Would sure like to be in Valdez now, reeling in slabs.

Dusty

Da Nag · Posted: Wed Jul 28, 2004 1:03 pm Post subject:

Good advice as always, Dusty - but in the case of the 22, it's not always "improper" loading that causes the need for lateral trim. Whenever possible, I do try and move things around to get as good of a natural balance as possible, but it's not always feasible.

Take the case of 3 adults and a full water tank - there's nowhere to put all of that weight except to port. And if you have your kicker to port as I do (which makes for a better natural balance when going alone, as I often do), there's even more weight to port that can't be moved.

Still, points well taken - I agree, the least amount of tab that will do the job is preferable. Hopefully, the tweaks I've got in mind will address the problems I have with the Lencos when loaded as described above.

I think TyBoo hit the nail on the head - it's not so much the size of the Lencos, as it is the actuator travel.

Da Nag · Posted: Wed Jul 28, 2004 1:11 pm Post subject:

Da Nag · Posted: Wed Jul 28, 2004 1:21 pm Post subject:

Sawdust · Posted: Wed Jul 28, 2004 2:54 pm Post subject:

You are right, Mr. DaNag --

There are times you just ain't got enough! In my airplane jock days I've known fellers who would put all the passengers on one side and use trim to level -- works!!

And your example of 3 pax, full H2O, and kicker all to port is a perfect example of why you need tabs... and if I loaded like that I'd surely increase tab area. Either that or eat a lot more... of course being the tightwad I am, I never carry more fuel or water than a safety margin for the trip, and never full fuel starboard along with the diriver -- and empty fuel port. Not enough tab for that. And extra weight really sucks up gas... of course Californians don't care. Laughing

The Orca is a good case in point re tabs. Those barn doors they call tabs should be elevators on a 747. I've given myself a good case of heartburn in Deception when forgetting to get 'em all the way up. But with the 200 gals of fuel, full water, full hot water and full holding tank plus a heavy I/O - an option I'm happy I don't have (yuk), gotta have tabs to grunt out of the hole with a full load of pax. Just a tad of down dab at cruise really digs the nose in to where she bow steers. Lot of trust by the builder, because improper use of these tabs in a heavy sea could be frightening.

Dusty