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Author Topic: Offset trim tab anodes???  (Read 2898 times)

February 15, 2011, 12:43:36 PM
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TheKid

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Offset trim tab anodes???
« on: February 15, 2011, 12:43:36 PM »
What's the thought behind offset trim tab anodes? I mean the fin is shifted to port about an inch.

I have one on my 140 Tohatsu and it is very difficult turning to port.

I'm wondering if I get an inline one it will alleviate this some?

February 15, 2011, 12:53:04 PM
Reply #1

fitz73222

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Re: Offset trim tab anodes???
« Reply #1 on: February 15, 2011, 12:53:04 PM »
That is intentionally adjusted that way to counter the effects of steering torque. The normal adjustment technique is adjust towards the direction of the pull. If you are pulling to port, adjust the tab to port.
1973 Aquasport 22-2, twin 115 Mercs
2000 Baycraft 175 flats boat, 60 Bigfoot Merc
1968 Boston Whaler 13, 25 Yamaha (project)
1966 Orlando Clipper 13, 9.9 Merc

February 15, 2011, 01:38:18 PM
Reply #2

TheKid

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Re: Offset trim tab anodes???
« Reply #2 on: February 15, 2011, 01:38:18 PM »
The boat is difficult to steer to port. That would mean it would tend to drift to starboard with out holding onto the wheel.

The tab is offset 1" to port and positioned parallel to center line.

So you are saying the tab should be offset to starboard?

I understand adjusting/twisting the tabs. Just not sure of the offset.

February 15, 2011, 01:48:14 PM
Reply #3

fitz73222

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Re: Offset trim tab anodes???
« Reply #3 on: February 15, 2011, 01:48:14 PM »
It sounds like the tab is adjusted correctly. The steering wheel pull can be drastically affected by your trim angle also.
1973 Aquasport 22-2, twin 115 Mercs
2000 Baycraft 175 flats boat, 60 Bigfoot Merc
1968 Boston Whaler 13, 25 Yamaha (project)
1966 Orlando Clipper 13, 9.9 Merc

February 15, 2011, 05:30:06 PM
Reply #4

seabob4

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Re: Offset trim tab anodes???
« Reply #4 on: February 15, 2011, 05:30:06 PM »
On a single engine boat, the tab (called a torque tab), it's trailing edge should be at about 1:00...


Corner of 520 and A1A...

February 15, 2011, 06:29:01 PM
Reply #5

TheKid

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Re: Offset trim tab anodes???
« Reply #5 on: February 15, 2011, 06:29:01 PM »
I'm not making myself clear.

I know what a torque tab is. I understand the principle.

I DO NOT HAVE A NORMAL TAB.

My tab is offset, shifted, not on center-line. I'm not talking about rotation, degrees or anything like that.

When I set it up straight, 12:00, 0 degrees, it is not on the center-line of the boat. It is shifted one inch (1") to port.

I am trying to figure out the reason for this. Not how any tab works. Why is my tab shifted? Is it necessary?




Let me add that this is not my tab, but it is close in that it shows what I am talking about. My tab is similar, yet it has threads on the back side to mount from the top. This one requires a through bolt, possibly the reason it is offset.

February 15, 2011, 06:43:23 PM
Reply #6

TheKid

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Re: Offset trim tab anodes???
« Reply #6 on: February 15, 2011, 06:43:23 PM »
Ohh no.

Perhaps I stumbled over my own answer. Maybe it is the mounting. I did not notice but perhaps it is through bolted.

Still, why do you suppose they would do that rather then run it straight down the middle.

February 15, 2011, 07:04:39 PM
Reply #7

seabob4

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Re: Offset trim tab anodes???
« Reply #7 on: February 15, 2011, 07:04:39 PM »
Never seen one like that... :scratch:


Corner of 520 and A1A...

February 15, 2011, 08:54:05 PM
Reply #8

TheKid

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Re: Offset trim tab anodes???
« Reply #8 on: February 15, 2011, 08:54:05 PM »
Come on Bob, I didn't think I could stump you with a question.

I've since noticed that Nissan/Tohatsu and Suzuki use this type.

I've never seen it either and I have one.

It doesn't seem it would be as effective as a center-line one due to the fact that it gives the thrust/force more time/distance to dissipate before interacting with the tab.

In any event. The boat holds a steady course yet is extremely difficult to turn to port.

February 15, 2011, 09:28:14 PM
Reply #9

Capt. Bob

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Re: Offset trim tab anodes???
« Reply #9 on: February 15, 2011, 09:28:14 PM »
Quote from: "TheKid"
The boat holds a steady course yet is extremely difficult to turn to port.

Hydraulic steering?
]
Capt. Bob
1991 210 Walkaround
2018 Yamaha 150 4 Stroke
"Reef or Madness IV"

February 15, 2011, 09:39:05 PM
Reply #10

seabob4

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Re: Offset trim tab anodes???
« Reply #10 on: February 15, 2011, 09:39:05 PM »
Quote from: "TheKid"
Come on Bob, I didn't think I could stump you with a question.

I've since noticed that Nissan/Tohatsu and Suzuki use this type.

I've never seen it either and I have one.

It doesn't seem it would be as effective as a center-line one due to the fact that it gives the thrust/force more time/distance to dissipate before interacting with the tab.

In any event. The boat holds a steady course yet is extremely difficult to turn to port.

Not the Suzi's I know, 90 and up... :scratch:


Corner of 520 and A1A...

February 16, 2011, 11:22:08 AM
Reply #11

Skoot

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Re: Offset trim tab anodes???
« Reply #11 on: February 16, 2011, 11:22:08 AM »
Im not sure why its offset either, but Mine looks just like that. I recently installed new one (from the Tohatsu dealer) and it's exactly the same.
Scott

1975 19-6 - 90hp Tohatsu

February 18, 2011, 06:53:38 PM
Reply #12

TheKid

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Re: Offset trim tab anodes???
« Reply #12 on: February 18, 2011, 06:53:38 PM »
Quote from: "Capt. Bob"
Quote from: "TheKid"
The boat holds a steady course yet is extremely difficult to turn to port.

Hydraulic steering?


Actually...uh...errr...not sure, being my second outboard. It feels and looks like cable. The only reason I think otherwise is the two cables or actuators going to the motor. My previous Mercury only had one cable.

You tell me! There would be a pump somewhere...correct? I plan on going through everything again this weekend.

What difference would it make in relation to the hard steering to port? Plugged line?

I am going to disconnect the motor and crank her left and right. Perhaps one of the cables, if it's cables, needs to be replaced or lubed.

One could think I would be embarrassed asking these questions. I really dont care. Between the thick skin and just wanting to get things right...if I don't know, I ask.

That's the whole point of the board right?

February 18, 2011, 07:06:31 PM
Reply #13

seabob4

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Re: Offset trim tab anodes???
« Reply #13 on: February 18, 2011, 07:06:31 PM »
The Kid,
If you don't have a steering cylinder in the tilt tube, you have dual cable steering...


Corner of 520 and A1A...

February 19, 2011, 09:51:50 AM
Reply #14

Capt. Bob

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Re: Offset trim tab anodes???
« Reply #14 on: February 19, 2011, 09:51:50 AM »
Quote from: "TheKid"
Quote from: "Capt. Bob"
Quote from: "TheKid"
The boat holds a steady course yet is extremely difficult to turn to port.

Hydraulic steering?

One could think I would be embarrassed asking these questions. I really dont care. Between the thick skin and just wanting to get things right...if I don't know, I ask.

That's the whole point of the board right?

You are correct. Thick skin is a premium on any forum site and is to be coveted.
That stated, pics can often help with forming answers.

If it were hydraulic, as Bob stated, you would have the mentioned cylinder and lines. The supports of the steering rod must rotate freely for a smooth turning action.
Does this look like what's attached to your engine?

]
Capt. Bob
1991 210 Walkaround
2018 Yamaha 150 4 Stroke
"Reef or Madness IV"

 


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