Lenco Trim Tab Upgrade (Again?)

[Chop~Chop]

Hello All, I've been far-of-field for way too long now, and I hope to be able to contribute this year...

I'd like to get advise on doing the 12x12 to 18x12 Lenco swap.
It's been way too long and I got to get it done for this season before splash day.

I want to leave the actuator in place and mount the outside edge of the new tab exactly where the outside edge of the 12x12 is now.
Doing so, will somewhat obviously, places the center of an actuator 6" from the outside edge of the tab, as it is now, and 12" from the inside edge.

I've re-researched most (maybe all) the post and even found the one that actually answers the question I'm asking myself again.
http://classicparker.com/phpBB2/viewtop ... 18&start=0
I had actually forgotten I called Lenco back in 2006.

But I'm always second guessing myself, so I hope many of you could chime in on this.
Last week, I called Lenco again, and I got a different answer...go figure, definitely a different Technician.

Has anyone done with success?
Will there be too much stress on the actuators OR the tab hinge itself?

I haven't thought through which situation would be worse; a MV hull like mine, or a DV in 4' chop at 25knots.

I just want to be sure the sum of the moments and sum of the forces stay very very close to zero :shock:

Thanks, Mark

 

[96TL]

Todd @ Lenco did not recommend offsetting the actuator. I am doing the same upgrade. I already have the blades, just haven't had the time.

This is his email:

The blade must be centered to the actuator. If the blade is mounted and the actuator holes in the blade don't match up with the actuator, it will cause binding when the tab is deployed.

 

[grouperjim]

There are always many different ways to do a project. For me, I never seem to pick the easy way, but usually it's the right way.

Regardless of the tab position, the actuator should be centered on the blade. This is especially true with a Lenco blade because they use a "piano wire" style hinge which will bind if the force is imparted off center.

For me I like the electric Lenco actuators but prefer the blade and hinge design of the Bennett tab, so I integrated the two for the best of both worlds. Plus the Bennett blade can be mounted flush with the bottom of the boat (the Lenco has to be raised a bit to eliminate spray though the hinge). That being said, it was very easy to clip the wire (inside the bilge) to the Lenco actuator and pull it through. Then redrill and reposition the actuator to be centered on the blade. Just splice the wire on the inside with some waterproof butt connectors. This will also come in handy in the future when you need to do an actuator replacement due to damage or failure.

The last step is to fill the previous actuator holes with some marine tex and later rough up the marine tex and finish off with some Parker gelcoat. No sweat.

Here is a couple pics of mine.

 

[Chop~Chop]

Thanks Dom, Tom's point on hinge binding makes sense. Especially while underway, adjustments would be either impossible, or inevitably the electric motor would be overstressed to often and burn out prematurely.

I had thought there'd be excessive stress on the hinge, but I was actually worrying about it bending or ripping itself from the transom.

Jim Thanks, I'm going to get it done...move the actuators and get the Bennett tabs. This is the most expeditious approach with one caveat.

Joshdad's method here has him all set to switch over the be all Bennett if/when the Lenco actuators let go.
http://www.classicparker.com:80/phpBB2/ ... blade+prop

Now Getting the whole Bennett kit with or with out the Euro style control switch or just the tabs is the next decision, I think.

It may be good to have the Tab Indicator Control especially if I go with the 30x9's.
Not sure though if my rig really needs them, or if the 24x is all that's necessary on the MV hulls.

 

[Megabyte]

If you decide to purchase tabs, BOE Marine is having a sale on them until the end of the month.
See here:

http://www.classicparker.com/phpBB2/vie ... php?t=3870

 

[96TL]

I swapped mine this weekend. 8)

http://www.classicparker.com/phpBB2/vie ... php?t=3983

 

[Chop~Chop]

Congratulations Dom, I've made some progress.

The 30x BOE tabs are getting their second coat of Tie Coat Primer
tomorrow.

I'd like to get some inputs on pros and cons of different methods for patching the tab hinge holes.

Marine Tex:
http://www.marinetex.com/PRODUCT%20PAGE ... 20PAGE.htm

or

West Marine's Penetrating Epoxy followed by a two part epoxy resin/harder,
i.e., West System or raka.

or

3M Marine Filler Vinyl Ester; This looks interesting.
http://solutions.3m.com/wps/portal/3M/e ... s/Catalog/

I think preparation of the new holes for the Bennett actuator and hinge mounts is not all too different.

Since the Marine Tex Epoxy Putty can also be sanded, drilled, and tapped;
I'm thinking, maybe using a penetrating epoxy followed by the Marinetex may be best for both cases (patching old and prepping new)?

Regardless, I suspect I should be prepared to have a little tool available to pack the stuff into the holes.

I'll surely counter-sink the holes to ensure there's a uniform surface to bond and ream out the left over caulk...beforehand.

BTW
This stuff, "OOPS", worked well to soften the polysulfide based caulk
used at the factory. Surprisingly, the website doesn't say it's safe
on FRP but, it does so on the package...
http://www.homaxproducts.com/products/c ... index.html

At this rate I'll be in by Memorial Day... :roll:

 

[Megabyte]

You got the 30" tabs?
Which ones...? 30x9 or 30x12?

You are going to so love the performance. 8)

 

[Chop~Chop]

I decided on the 30x9. I figured they'd be a little (lots) more forgiving
when I get in a following sea and/or takin'em astern at 45...

I'm contemplating the complete change-over to hydralics without needing external line...I'll keep you posted.
I just got to figure out how to get the Lenco tab switch to control the pump...

This is gonna be a whole differnt boat; I think it'll actually run like it looks it should...I've waisted 4 years :evil:

But please, get me over this step of prepping and drilling holes in my rig for the first time :shock:

Thanks, Mark

 

[Megabyte]

But please, get me over this step of prepping and drilling holes in my rig for the first time :shock:

Those tabs are going to be awesome!

Prepping and drilling the holes are pretty simple and have been covered several times here recently. Have you see those posts where the holes were drilled oversize and filled with thickened epoxy?

 

[Chop~Chop]

Kevin, I guess you are referring to these two.
Are there others?

http://classicparker.com:80/phpBB2/view ... ight=lenco

http://classicparker.com/phpBB2/viewtopic.php?t=1747

Also, While we're at it:
Why not mount the new tabs, say, 3-4 inches inboard?
I'll loose some lateral adjustment, but my hydrodynamic analysis says I'll gain lift...With no PH forward and a 584# 4-stroke 3' off the transom I need all I can get.
Does this make sense?
Besides, if I go far enough inboard without violating the 8-10" clearance to the prop, I'll likely clear that stringer and have easy acess for the indoor plumbing.

 

[Megabyte]

Kevin, I guess you are referring to these two.
Are there others?

http://classicparker.com:80/phpBB2/view ... ight=lenco

http://classicparker.com/phpBB2/viewtopic.php?t=1747

Also, While we're at it:
Why not mount the new tabs, say, 3-4 inches inboard?
I'll loose some lateral adjustment, but my hydrodynamic analysis says I'll gain lift...With no PH forward and a 584# 4-stroke 3' off the transom I need all I can get.
Does this make sense?
Besides, if I go far enough inboard without violating the 8-10" clearance to the prop, I'll likely clear that stringer and have easy acess for the indoor plumbing.

There are others, but those are good. GW204's method is especially good (IMHO), and has been used by a number of folks here. He has more experience with this method than I do.

One other thing you might want to consider is to use 3M 4200 rather than 5200. 3M 5200 is pretty much a permanent sealant as it contains a powerful adhesive in addition to the sealant. 4200 is a bit more forgiving if you ever need to remove and rebed a part sealed with it.

For above the waterline use, I've been using 3M 4000 UV for bedding deck items. Below the waterline, on items that might have to be removed someday, I use 3M 4200. For items that will never be removed, I'll use 3M 5200.

As for placement on the transom, I would take transom photographs of your application and send them to Tom McGow at Bennett and get his opinion and advice. Toms email address is [email protected]

For that matter, post the photos here and direct Tom to this thread (he is a registered member of CP). That way everyone benefits from his helpful advice. :wink:

Good luck!

 

[Chop~Chop]

Here are some pictures to provide perspective of my rig. The total distance from the outer edge of the original tab hinge, measured at the very bottom of the transom, to the garboard drain is 45.5".

Initial measurements show, with outer edge of new 30x9 tabs placed ~7" inboard, the actuator mounting hinge will end out just beyond the 6th bolt about an inch above the water line. The inner edge of the tab edge ends out ~8.5" from the drain. This will allow for clearance from the inner obstructions and allow access to hydraulic fittings and for line routing. The magic number in the Bennett installation guide is 8".

I'm trying to get an idea how performance will be affected, i.e., I might gain lift but. I'm questioning how adjustment for running in a quartering sea may be affected. There are probably other considerations I haven't thought of yet; can you opine?

Thanks, Mark

 

[grouperjim]

Mark:

If I am understanding your posts correctly, you want to reposition the entire tab further inboard towards centerline.

If that is the case, I would not advise moving the outside edge of the blade any further inboard. Keep the outside edge even with the existing outside tab edge, with 30w tab max for your beam.

The tab companies provide guidance for minimum distance from the inboard edge of the blade to the centerline. Their minimum distance is predicated on an engine that sits closer to the actual stern of the boat.

The rub in this case, is that of course your engine sits back a few feet on the bracket. Because of this setback, the A/V plate has been been positioned significantly higher than the bottom of the hull. The problem in using the minimum recommended distance from centerline is, the turbulence/contrail of water coming off the inboard edge of the blade converges inward towards centerline as is travels aft. When that prop is sitting a few feet back on a bracket, that "dirty" water affects the clean water that the prop needs to be efficient. When the engine is not on a bracket, the convergence of "dirty" water from the inboard tab edge happens well behind the prop.

jim

 

[DaleH]

I too would leave the outside edge where it was, but in no circumstances would I go further out. NOTE - with tabs put where you have them, in emergency situations, you can acutally STEER the boat by just using the trim tabs alone. Try it. You'll loose considerable manueverability ... but it will get YOU home ...

Regarding a quartering sea ... head-on or stern-to? When taking such seas head-on, I find I get a significantly smoother ride by raising the weather-side of the hull up as far OUT of the water as I safely can, without going overboard (literally ). This does, however, require the Capt to really pay attention, which you should be doing in seas anyway.

Stern-to seas, if seas where on the starboard quarter, I lift up the starboard tab and push 'down' on the port one, which raises the port side of the boat ... this helps the boat leand with a smaller smash into the seas, as I'll be running faster than the seastate.

Now remember, I run a real-time fuel efficiency calculator, so I can instantly see the effects my tabs are doing to my performance. I can typically find a sweetspot where the ride is acceptable and optimizes the fuel burn.

Little known secret I've discovered (using the fuel computer) ... unless seas are in-line with the boat, I'll can dial in 10-20% BETTER fuel efficiency by only using one trim tab! Again, get the weather-side of the boat out of the chop/slop/waves and you too will see improvements!

Now yes ... the boat is heeled a bit, but I am only talking only a few degrees and NOT being redically heeled. Try it! Point is, by using just one tab, you'll be surprised what it can do and even one a tad deeper is much better (fuel wise) than 2 deployed.

 

[Chop~Chop]

Thanks Guys,

Dale, I was referring to exactly the two scenarios you described in a quartering sea stern-to and head-on. I think with the tabs placed inboard too much, I'd end out with a tendency to drive the bow down rather than be able to effectively adjust as you described.
But your stern-to adjustment confuses me; raising the starboard tab and deploying the port one, I think would raised the starboard side of the boat, not the port.

Jim, Thanks. I'm surprised though.
My first reaction was I need to see a video of this…I think I have it in the archives.

I spoke with a nice fellow at Bennett today. He wasn't too interested in looking at this.
He did say your point is well taken, but nothing is certain, i.e., 50/50 chance it would be problematic with only 10" clearance.

I'm going to measure more accurately and actually do the trig to figure out if I can get closer to 10" clearance.
And if that doesn't work out, then I'll either start over with 24x9 or x12…

I really want indoor plumbing.

BTW, Dale, did you do some major surgery to get your hydraulics installed?

I haven't made contact with Tom McGow yet...I sure hope he looks at this.


Thanks Again, Mark

 

[grouperjim]

Mark: Actually, I do have some video I shot of the tab vortices from my 24w bennetts where they converge on the A/V plate. Speed is 35 mph. Tab 2 bars down.

Here is a pic from that day. I'll put the video on YouTube later this evening, and post a link here.

jim

 

[DaleH]

But your stern-to adjustment confuses me; raising the starboard tab and deploying the port one, I think would raised the starboard side of the boat, not the port.

Deploying or putting a port TAB down (not the port tab SWITCH), but the actual tab itself, causes that side (port) of the boat to lift.

 

[grouperjim]

Check out my video of the 24x12 vortices. Please hold any comments about the height of my A/V plate. Through trial and error (moving it up and down) it IS set at the optimal height for the sea conditions in my area. Any higher and there is unacceptable ventilation in a following sea. This video was taken prior to install of the Permatrim.

The inside edge of the blade measures 16" to centerline.

FWIW it ended up back in the top hole which is where the factory put it to begin with. Enjoy.....don't try this at home. For you guys that have not splashed yet......turn up the volume and pop open a beer.

http://www.youtube.com/watch?v=lnxvCqP8RaU

 

[Chop~Chop]

Jim, I've viewed it seventeen times already...

At the 00:06/7 mark when your foot is in view, the turbulence seems very very close to the motor. Similarly, at 00:19/23 it seems awfully close too. I don't mean to digress but could this turbulence be from the bracket tub?

At the 00:28/29 mark of the flick the vortices are most evident and appear 24" apart. It also appears the inner one is significantly further away than it was on the starboard side. Wonder what's up with that; maybe your guy/gal at the helm was coming to starboard?

I'm still doing the trig but continually confuse myself and invariably determine I got to go make another measurement...
So, I have big favor to ask; can you let me know the distance from the inner edge of your tab to the garboard drain measured along the bottom of the transom? I think it will also be useful to know the distance from the tab edge to the "centerline" measured horizontally.
For your deadrise these measurements could be several inches different.

I ask about the bracket tub because I spoke with a very helpful gentleman at Armstrong today. I'm trying to solve a ventilation problem I've had from the get-go. He asked me if the tub was out of the water when I'm on plane; I suspect I'm often not...especially the end of the tub furthest away from the transom. My motor is mounted on the top hole, it is down as far as it can go. I was thinking that raising it one hole might help and get this rig to plane correctly...But I'm gonna take it one step at a time tabs first...

Thanks Again, Mark