hanging trim tab

[pascavone]

pull my boat out of the water for the winter, and had one trim tab hanging off from the hinge, and the other one working its way out of the hing 1/2 of the way already.

Both were not damaged or bend, and the pistons work.

Any ideas why they are working their way off the hinges?

The hing is basically a crimped joint, so I would think it's suppost to pop out, if there is a problem and not rip a hole in the boat.

I just got this used boat, and suspect someone was playing with the trim buttons to much and wiggled them out, or just extended them to much and popped them out.

I'd post a photo, but don't know how to do it on here.

[seapuppy]

send me the photo at steve.stephens1@frontier.com

I'll post it for you...you can select the little picture frame above..when you put your cursor over it..it says insert image....
you picture must be saved in some sort of sight...a free picture posting site or put it in an album here...

SP

[pascavone]

i spoket to Bennett, they said the end of the hinge attached to the boat should be crimped to prevent travel, but the tabs are 10 old, so it might be wore.

replacement is $29 bucks.

I think i'm going to install the LED tab indictor switch at the same time to make it easer to how were they are.

[seapuppy]

sounds great.....I would replace them and maybe add the auto trim tabs too....I sure love mine....works quite well....

SP

[ss3964spd]

I don't think you can just add the LED tab indicator switch (EIC) without also swapping out the hydraulic rams.

The rams used with the EIC have sensor wires added to them so they can provide feedback to the EIC for tab position.

[seapuppy]

sorry I'm so late about this..but I've been trying to figure out where to host it....finally I went over to my album in the boc...

SP

[ed & inge]

hai pascavone

as far as i can see and think.....look at the top of het pistons where the are connected to the plate that's mounted on de boat, to me i think that is cracked or bended at the top of the cilinders on both sides (right side more then the left so that is why the right one totally got out of his rail) if you are going with full speed and using the tabs all the way down tot keep the boat in line for a long time or time after time, the smaller parts of the cilinders can't stand the power of the water..mostley it takes yust a few clicks with the tabs to keep your boat in line ore straight to the water, when i was going with a lot off people on the lake with
my 28 bayliner i had some years ago, i sometimes asked them to take another place in the boat so that it was not neccaserry to use the tabs all the way down....so inspect the hinge parts of the pistons/cilinder at the top were the go into the plate installed on the boat i quess the plastic is tortuonaled/bent and cracked

greatz ed

lets wait on some more reactions.......it's just my idee as far as i can see on the first picture because the cilinder/piston is not standing straight in line with the plate mounted on the boat

succes with it

[shrew]

WOW!!! I doubt that this is the result of someone 'playing' with the tab buttons. I play with mine almost constantly while underway. This looks like a part(s) failure or some unknown external force at play here (PO hit something......maybe?) I doubt we'll ever know the true root cause. Regardless of cause this will obviously not due and needs to be fixed.

I have to agree with Ed, I don't believe the attachment point of the ram on the transom as well as on the tab itself is not designed for lateral movement like that. It looks like the attachment point at the top of the ram is twisted. I wouldn't be surprised if it's tweaked on the tab as well. You could probably bend the metal back to be close to inline. I'd also be concerned with stress cracking and be worried about further failure in the future. A mechanical engineer could probably shed more light on this. I'm just a Computer Systems/Network Engineer, and not a 'real' engineer.....LOL (If only we had a knowledgeable mechanical engineer on this site...........................)

BTW-Bennett said it was $29 for the tabs or just the hinges?

[ss3964spd]

Those are ugly photos.

The trim tabs certainly appear to be Bennetts - their "drop fin" design, which are typically used on applications where a larger flat tab is needed but there is not enough room for them.

The back edge of the tab is bent to an obtuse angle, which then slides into the slot created by the mounting and backing plates fastened to the transom. The tab is retained in the slot by short bent tabs on the mounting plate - left and right sides.

Here's my take. If you look at the transom you will see that it is not "flat". Meaning, with the hull sitting level, if you were to hang a plumb line from a point on the transom above the out drive you will notice that the line does not come close to touching the the transom at the drain plug. What this means is when the tab is mounted it is physically angled inward (think "toe in" from the automotive world).

Now, with regular flat tabs this isn't an issue. But with the drop fin tabs it is an issue. The water coming off the bottom of the hull below the tab mounting plate is flowing parallel to the hull. But the drop fins of the tab are not parallel to the hull so the water hits the side of each fin. The tab's fins are effectively re-directing the water flow inward towards the centerline of the hull and as a result I would suspect a great deal of lateral stress is created on the trim tab assembly. Indeed, The port tab appears to have been pushed outward to port, and the starboard side looks like it went starboard.

You need to replace those drop fin tabs with regular flat tabs.

Dan

[ed & inge]

ppppffffttttt.. shrew i'm already happy that everybody (i hope) understands what i try to explain......

and an what you said about the flat tabs.......i had the same on my bayliner and i didn't had that problem the bended part makes the tab stronger, maybe it's an idee to get the most of the bended side part of to try if it works, buying new tabs is always an option if it does'nt work my opinion is still the former owner or himself has used the tabs to much and to fast (not in little steps but in one move from up to all the way down, you have to do it in little steps, i always did that) when he was already on top speed, the power that comes free......i think the tabs and pistons cant handel that.

greatz, ed

[ss3964spd]

Turn on your kitchen faucet then hold a knife horizontal - with the cutting edge straight up, under the water flow. The water flows over the edge and down the sides with little disturbance. Slicing through the water.

Now rotate your wrist - even just a little. The water starts to splash a bit and you can actually feel the difference in your hand.

That's what is happening to those tabs. My assessment is that constant lateral pressure from the water acting on the sides of the drop fins was pushing the trim tabs hard against the small tab that is meant to lock them into the mounting plate slot. With constant pressure against the locking tab and constant up and down cycling of the tab the resulting metal to metal contact either wore the locking tab away, or the force being applied to the locking tab simply bent it. End result is without the locking tab doing it's job the trim tab - with lateral force being applied to it from the water and constant up and down cycling, simply worked it's way out of the slot.

[pascavone]

mmmmmmmk,

I gave the port side tab an attitude adjustment, and the starboard side I unscrewed the two screws at the bottom of the actuator and then gave it a pounding back into it's slot.

All looked good again, and they worked just fined up and down.

So, how did it happen.

let's think about this.

If the tabs were in the full up position, then they hide behind the trasom and would have been protected under the water, and they would not be in use.

If the tabs were in the full down position, running at full speed, or hit a sand bar, then i could see them poping out of this crimbed hinge joint.

At full speed and a loaded boat, the water force would blow them off.

The problem is you can tell it there up or down when their under the water, so I'm going to put the LED indicator system in.

[seapuppy]

one problem with you just loosening the screws...you've now broken the bedding of the silicone sealant that is used to seal the transom from water intrusion.....you need to pull those screws completely out...squirt some silicone sealant in the holes and then re-run the screws back in......water will enter the transom and rot it out in no time...


SP

[pascavone]

Without having the trim tabs in hand to inspect, either the Hinge Plate has failed or the tabs were pushed outboard by a forklift spreading the forks outboard after lifting or just before lifting the vessel.

Bennett Marine, Inc.

[shrew]

It is my understanding that Bennett Marine designs these particular tabs with the fins to achieve the same amount of lift with less surface area on the tab. However these tabs are only recommended for boats with a complete flat transom which runs at a perfect right angle to the keel. Some boat manufacturers design their transoms with a convex shape. The tabs in question, with the fins, are not suitable for boats with a convex shaped transom. The flat part of the tab should be inline with the hull, however the 'fins' will (should, at least they do in my boat) stick below the hull like a keel or a rudder in the water.

The theory that water has pushed these tabs out of alignment makes the assumption that the transom is not a true flat 90 degrees to the keel. It is my understanding that this type of tab was standard on MAxum boats from the factory. If the Maxum transoms are not completely flat and a true 90 degrees from the keel all the way across, then MAxum has been installing the wrong type of tab as standard equipment. I doubt that is the case.

One way to tell would be to run a stright line across the back of both tabs allowing the lines from each to meet in in the center of the boat. If the lines meet and make a straight line, you are using the correct tabs. If the lines meet and make a triangle, the transom has some convex shape and the tabs with fins should be removed and replaced with a wider completely flat tab.

I noticed Pascavone signed his post with "Bennet Marine, inc." Pascavone, do you work for Bennett? If so, could you shed some additional light on this subject?

I like the 'forklift' theory.

[seapuppy]

my tabs have the drop fins on my 340...the forklifts have bent the crap out of them...so..even if they are in the fully retracted position..they get beat up......so....I'm thinking of changing over to the flat ones....with that said...a forklift can sure bend the crap outa them...


SP

[pascavone]

i just copied/clip what the Bennett Marine, Inc. guy thought.

2 each TPA1212DF Trim Plane Assembly 12 x 12 w/ 3" Drop Fins $153.00 each retail
1 each A1101CPEIC Actuator w/Port side EIC Sensor & Rod $111.00 each retail
1 each A1101CSEIC Actuator w/Stbd side EIC Sensor & Rod $111.00 each retail
1 each EIC5000INT EIC5000 Less All Wire $219.00 each retail
1 each EIC201 EIC 20' Wire Harness $90.00 each retail

The above part numbers will give you new tabs, actuator w/EIC sensors & the EIC5000 system to complete your retrofit. Please use the part numbers to shop around for your best deals and to place your order with any of your local marine dealers, catalog &/or Internet retailers.

[shrew]

Sorry Pascavone. I just reviewed the original thread and see that you actually created the post. Obviously if you worked for Bennett you wouldn't be reaching out here for advise, then posting a proposed solution/suggestion to your own post. That was a huge oversight on my part. My apologies.

So the next question is, does your yard use a forklift for the boats or a travel lift? If the boat hasn't come across a forklift since you last launched it (assumign the tabs were positioned properly prior to launch) then this might not be your culprit. If it is a forklift, you may want to have a conversation with the yard manager about what happened.

[pascavone]

shrew, no need to apologies, only thing in here are lies, and intresting lies!

I bought the boat, and never took it out of the water until a week ago for winter storage and put it in my yard.

Long island south bay, is a big pudddle, and low tie renders most of it under 24".

It's possible the previous owner hit an under water forklift......