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Author Topic:   Trim Tabs on a Montauk
mikeyairtime posted 09-09-2004 11:40 AM ET (US)   Profile for mikeyairtime  
[Are] trim tabs on a Montauk [a practical idea]?
DaveS posted 09-10-2004 08:33 AM ET (US)     Profile for DaveS  Send Email to DaveS     
I seem to recall someone talking about doing that about a year or two ago. From what I remember, most felt it didn't need them. And there there was no wood in the transom at that point to reinforce the tabs. You should be able to research it and find it.

Another thing you might like to do is go [to the Bennett website and ask them].

Keep us posted. I'm sure there are others with that same desire.

Good luck.


bocaspiff posted 09-10-2004 08:48 AM ET (US)     Profile for bocaspiff  Send Email to bocaspiff     
I put Bennet Tabs with the Auto Tab control on my Newport and a 15' Sport. I kept the Newport in the water for years and never had a problem. The tabs worked great but I know a hundred guys are going to say you shouldn't put them on because of the backing issue. You can't beat Bennett Marine for their quality.
mikeyairtime posted 09-10-2004 09:28 AM ET (US)     Profile for mikeyairtime    
The primary hurdle I see is running the hydraulic lines through the transom. They're designed to go straight through the transome and at the tab location the 170 Whaler is about 18" of foam core and then cockpit.
JohnJ80 posted 09-10-2004 10:04 AM ET (US)     Profile for JohnJ80  Send Email to JohnJ80     
The big names in tabs are Bennett and Lenco. My preference was Lenco since the installation is the easiest (all electrical). Both are great companies with great customer service and great support for their products. You can't go wrong with either. It is really just personal preference.

Bocaspiff is right, a million guys are going to come out of the woodwork and tell you that they are not needed - the vast majority have never had them and only slightly less will have ever used them. But tabs do have a place and it depends on what you are doing with your boat and what problem you are trying to solve. Can you tell us more about that?

When I put them on my Dauntless, I spent a lot of time talking with both Bennett and Lenco tech support and you should do the same.

There was no issue in my case since the overlap in fiberglass layup is significantly thick at the bottom of the hull where the tabs mount. In addition, the force on the tab is in shear (parallel to the surface of the transom) which means you need much less backing to begin with. The place where the max force is placed on the screw is when you go backwards in the water - then the force is trying to pull the screws out as the tabs are trying to be folded back under the boat by water pressure. Primarliy this force is at the mount of the the piston or jack screw on the transom. The tab screws are still in shear but less so than in the forward motion case.

In actual practice it is no problem. I have backed my boat down very hard to test this to the point where water comes over the transom. No problem.

I keep my boat on a jet dock so it is up out of the water. I have put it on the dock with the tabs fully extended and left it there for a week or more. This means that the tabs are jacking the weight of the boat up. No problem.

When I back off the jet dock, the boat actually is moving pretty fast backwards - again no problem.

Both Lenco and Bennett have put tabs on hundreds if not thousands of whalers and can tell you what they found (pretty much the same experience as mine).

To run the control lines through (hydro or electrical) you need to drill a hole. You can put the lines through and seal with 5200 and it should be fine. If you want, you can do the deal where you drill the hole, put a bent L shapped wire or allen wrench in your drill and use that to bore out a void in the foam. You can then fill this with epoxy, let it harden and then drill it again. You can do this for any of the screws you might worry about too. Then you have a big solid epoxy plug in backing the hole - but it really isn't necessary.

I found that with tabs I can really control the attitude of my boat to a seaway or chop thereby much smoothing the ride and keeping a planing attitude at much lower speeds. This is a big deal for me since I have a small boat on a pretty big river that has some really big boat traffic on it. We get lots of moderate to severe chop so smoothing this out is a big deal. For me, it was like adding 3' or more to my waterline.

Also if you have any porpoising, you can pretty much trim it right out.

So, we like them, but they are not for everybody and it depends on what you are trying to do.


FISHNFF posted 09-10-2004 08:33 PM ET (US)     Profile for FISHNFF  Send Email to FISHNFF     
I have a set of Lenco's on my 1998 Montauk/Alert 17 with a Merc 90 4S. Dogfish2 has a set also.

I had to mount the tabs more toward center. I know the further out, the better, but just wouldn't fit right. Here are some of my observations over the past few years.

The tabs can be used with the motor trim to smooth going into a head sea. I can get the bow up while keeping the boat level, using the V to better cut the waves not having the bow plow or bury, or try to launch upward.

I can compensate for steering torque/heel, weight imbalance, and trim laterally when running crossways to a chop. Makes the ride smoother and dryer.

I can adjust the tabs to minimize porpoising when trimmed out max.

I would like more adjustment out of the tabs. By this I mean I want them to lean the boat port/starboard more than they do. I think mounting them outward would be better, bet like I said earlier, it just wouldn't fit right. They are the Edgemount type.
I think the Bennet SportTabs, with their turned down edges, would catch the water better and increase efficiency. I still have some experimenting to do;)

As to strength, I really would not worry.
Last year at a lake, I had a buddy back the trailer down the ramp. He had it at the wrong depth, but he couldn't hear me with the A/c going, windows up, and music on.
In the lot, the boat was a couple feet short, and with the line long, my dim light went off and thought, "I'll just slam on the brakes!" Go...go...slam! Now it's 2 feet to far forward! A winchpost bracket let loose, allowing the post to tilt forward. At the stern, the port trim tab, which had been left down, was holding the hull off of the bunk. Lowered it down (no damage to tab or hull) and long story short, fixed everything and got home without incident.

Lenco was brand of choice for ease of installation. No pump to mount. Ran electrical wires over transon and through tunnel with other wires. Nice rubberized switch. Faster than hydraulics. Noisier? Only on trailer with outboard off. Motors are outside boat near motor.

The hull is 150lbs heavier than a standard Montauk. Larger console and extra HD rubrails through bolted at waterline. The motor is over 400lbs with SS prop and fluids. I also have a DoelFin and Hydraulic steering. 2 group 24 batteries are in the console.

Hope this helps,

FISHNFF posted 09-10-2004 08:43 PM ET (US)     Profile for FISHNFF  Send Email to FISHNFF     
Oh yeah, about the backing down thing. No problem.

We backdrift, or sometimes backtroll, for bass over reefs. I have not noticed any difference before or after tabs. Steers fine. Either way, you should trim the motor up to minimize water over the transom, especially with a chop. Anything over 2-3' and the boat goes bow first.


mikeyairtime posted 09-11-2004 01:29 PM ET (US)     Profile for mikeyairtime    
My primary question was how to plumb the hydraulic or electris lines. I wasn't aware they could go over the transom. I have experience with tabs. I had a Doel Fin and tabs on a 22' aluminum lobster skiff for years so I know they work. With full tabs and full trim it would plane at 11 to 12 knotts. I've already had my 170 25 miles out off Southern California and can get caught in pretty nasty conditions. The last 3 miles going into Los Angeles Harbor have the nickname Huricane Gulch for the wind that blows around the Palos Verdes Peninsula and can actually be the roughest part of the trip. As far as tearing off tabs, I've done it. I used to run a 45' Munson doing burials at sea out of L.A. harbor. On a trip the day after a Pacific storm had moved through and the clearing wind was ripping down the coast to fill in the low pressure void we did a funeral. 6' seas and a 15' swell and all I could do was try to hold the boat steady with the stern to the swell. If I put it in gear we'd go surfing off down swell, so I just kept popping it in and out of reverse to keep us pointed down swell and out of the trough. When we got back to port both hydraulic cylinders were broken off and the tabs were gone. All the hardware was still in the stern, the tabs had simpily slipped out of the two plates that hold them.
FISHNFF posted 09-12-2004 05:09 PM ET (US)     Profile for FISHNFF  Send Email to FISHNFF     
Yes Mickey, the Lenco wires are made to go over the transom. I know on our Grady, the Bennetts are plumbed through with brass fittings. This was a big concern when deciding brands. The tabs are actually hinged with a pin, as opposed to sliding into a slot like on Bennetts.


13_Dauntless posted 09-13-2004 01:26 PM ET (US)     Profile for 13_Dauntless  Send Email to 13_Dauntless     

My name is Christian, and I work for Bennett Marine. To answer your question about running the hydraulic lines, there are a few different ways to go about it. Standard Bennett trim tab kits use a brass fitting that runs through the transom directly behind the actutator upper hinge. The hydraulic tubing connects to the brass fitting inside the transom. This is typically the preferred mounting method as it leaves no exposed tubing or wiring outside the transom.

On some boats the inside of the transom is inaccessible or has a thick foam core. In these case we offer actuators with external tubing connections that allow you to run the hydraulic tubing through (or over) the transom where it is most convenient. We also have actuators with pre-connected hydraulic tubing. This allows you to drill through the foam core, and feed the tubing through the transom from outside the boat, eliminating the need for hydrualic connections inside the transom. We offer the parts for these alternate mounting methods on a no charge exchange basis. You can see illustrations showing these mounting options here:

Christian Redditt
Bennett Marine

Knot at Work posted 09-13-2004 01:37 PM ET (US)     Profile for Knot at Work  Send Email to Knot at Work     
Mikey, What is your Montauk doing that requires trim tabs? Slow to plane? What size motor you got?

I have not found a need to trim tab the Montauk, it planes rather fast.



mikeyairtime posted 09-13-2004 04:50 PM ET (US)     Profile for mikeyairtime    
Tabs are a nicety more than a necesity. To be honest I saw a Gradywhite add and they offered tabs on their 180 as an option and I got curious if anyone was running them on a Montauk. Simple as that.
mikeyairtime posted 09-13-2004 08:09 PM ET (US)     Profile for mikeyairtime    
BTW Knot at Work my primary need for tabs would be to reduce my planing speed for a smoother ride when it's rough, not to plane faster.
jimh posted 09-13-2004 09:18 PM ET (US)     Profile for jimh  Send Email to jimh     
The fellow from Bennett has participated in discussion like this on this forum, but it is really easier to just call them on the telephone and ask them directly.
jimh posted 09-13-2004 09:21 PM ET (US)     Profile for jimh  Send Email to jimh     
Oh--I didn't see the answer from Christian from Bennett. There you go, direct answer from Bennett right here. No need to go off into the web for advice. Thanks, Christian, glad to have your expert participation.
hooter posted 09-13-2004 09:25 PM ET (US)     Profile for hooter    
Yeah, count me as one o' the million guys. Slappin' tabs on a Montauk is like, well, stickin' another piece o' chrome on a Honda Goldwing (notice Ah didn't malign Harley, there). Any utlity some think they derive from such a setup is entirely imaginary. Whatever floats your boat, Ah guess, if wastin' money is your thing.

If you really think you just gots t'have trim tabs, go get you a grown-up boat that can use 'em, like startin' at an Outrage 22' or larger:-!

mikeyairtime posted 09-14-2004 05:37 PM ET (US)     Profile for mikeyairtime    
If you never run offshore you'll never understand the purpose of a set of tabs. There's more to them than just helping a boat plane with a couple 300 pound rednecks in the stern. Lifting the stern conversely plants the bow which allows the fine forward part of the bow to slice through chop when running uphill. It's OK, most boaters don't understand what tabs are for or understand how to use them so it's understand why someone may call their benefit imaginary. Someone who doesn't know how to use them can also get in a heep of trouble by running downhill with full tabs and the motor trimed all the way down. I once watched a guy broach a 23 Sea Ox that way. Stuck the bow into the back of a swell so hard the stern lifted out of the water and the boat did a sharp turn to port while comming to an abrupt stop. The bait tank ripped out of its mounts and slammed into the starboard rail.
JohnJ80 posted 09-14-2004 06:21 PM ET (US)     Profile for JohnJ80  Send Email to JohnJ80     
mikeyairtime - I agree with you 100%. This is exactly what I find them so useful for - adjusting the attitude of the hull to the sea way.

makes a big difference.


Knot at Work posted 09-14-2004 11:01 PM ET (US)     Profile for Knot at Work  Send Email to Knot at Work     

I meant no disrespect, but I ain't 300 pounds either, and I don't think bubba likes being called that slur...

p.s. I know what trim tabs are for... don't need any help in that department. Put em on your boat if you want...

mikeyairtime posted 09-15-2004 09:27 AM ET (US)     Profile for mikeyairtime    
Knot, I took no exception to your post. At the current time I don't think I'll be putting tabs on more for simplicity and cost reasons than anything else. Someday I may put them on. On the other hand calling tabs useless (I think comparing them to naked lady mud flaps on a pickup would have been more apropriate than chrome on a Gold Wing)and their benefit imaginary when guys are posting how they mounted theirs is pretty much trolling for a reaction.
In a duel one guy would take off his glove, slap the other guy in the face and throw the glove down.(throwing down the guantlet) The other guy had two choices, walk away or pick up the glove and slap the other guy back. I hope no one takes this verbal jousting too seriously. If I offend or am out of line I'm sorry.

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