# Trim tab issues



## Smackdaddy53 (Dec 31, 2012)

I don’t see how those tabs could cause enough turbulence for your motor to lose water pressure unless the stern is lifting enough with the tabs down that it’s causing your lower unit to come up high enough out of the water to ingest air. You should borrow a GoPro or have someone hang off the back and shoot video so you can see what’s really going on back there.


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## Battfisher (Jan 18, 2016)

That's a fairly heavy boat - wonder if the aluminum prop might be an issue as well.


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## Capnredfish (Feb 1, 2012)

If the problem did not exist before tabs then its the tabs. That's a lot of stuff disturbing the water back there. Lower motor one notch. And that prop is a pos. Maybe got rid of that fin now


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## Smackdaddy53 (Dec 31, 2012)

Capnredfish said:


> If the problem did not exist before tabs then its the tabs. That's a lot of stuff disturbing the water back there. Lower motor one notch. And that prop is a pos. Maybe got rid of that fin now


Did you read my whole post?


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## Capnredfish (Feb 1, 2012)

Yes. What about it? Guy adds tabs and it screws up the ride. Simple. Motor is not in water therefore it looses water pressure. Tabs either raise stern too much for his set up or hull design. Prop looses bite now because stern raised or poor water flow. If I missed something you said. Oh well. People read the Bible and skip parts or interpret as they choose. Now back to original question. Wtf is your point.


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## Salt of the Water (Feb 26, 2018)

Hung over the platform and looked at it this weekend while I had someone to help me run the boat, and at 3/4 or full down on the tabs it’s definitely “boiling” back there. Lots of turbulence, bubbles, etc. Two guys on the back bench sure doesn’t help with weight distribution though. 

Shooting some video is a good idea, I’ll try and set something up to film it and run some different scenarios.

I know my prop isn't ideal... have that on my list of thingstto try. I’m a little wary of going stainless because there’s lots of shell in the areas I fish and aluminum props are cheaper than bent shafts.


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## Smackdaddy53 (Dec 31, 2012)

Capnredfish said:


> Yes. What about it? Guy adds tabs and it screws up the ride. Simple. Motor is not in water therefore it looses water pressure. Tabs either raise stern too much for his set up or hull design. Prop looses bite now because stern raised or poor water flow. If I missed something you said. Oh well. People read the Bible and skip parts or interpret as they choose. Now back to original question. Wtf is your point.


You’re very rude...do you talk to your customers that way because some may be reading your smartass posts.
Maybe the tabs get the stern up and he needs to lower the motor now to fix most of the issue. Go get laid or chill out.


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## Capnredfish (Feb 1, 2012)

Smackdaddy53 said:


> You’re very rude...do you talk to your customers that way because some may be reading your smartass posts.
> Maybe the tabs get the stern up and ge needs to lower the motor now to fix most of the issue. Go get laid or chill out.


Take a look in the mirror. You wrote. Did you read my entire post. Like your special. I'm as nice a person as you will ever meet. However my humor can sometimes come across as sarcastic. I do both. Get laid and chill. Don't like what I write? Don't give me the satisfaction of a reply. Asswipe.


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## jonrconner (May 20, 2015)

No one has asked about motor trim, is it all the way down?
JC


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## Salt of the Water (Feb 26, 2018)

jonrconner said:


> No one has asked about motor trim, is it all the way down?
> JC


Trimmed all the way in. Shallow water hole shot was improved with full tab and full motor trim compared to before with no tabs. Other than the shut down due to overheating...

Once I figured out what was going on I was able to get up and then ease off the tabs and run ok. I'd still like to get the issue sorted out so I can stay on plane at slow speeds (shallow water or in a chop).


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## bonehead (Dec 9, 2016)

I also had a problem with my tabs about 3 months ago (also Lenco). One of them was unresponsive and after a while we just replaced both of them. Figured it was the best thing to do as they were about 15 years old anyway. Haven't had a problem since and they make for a much more smoother ride.


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## Capnredfish (Feb 1, 2012)

Hey Smack. You're alright. Let's put this behind us. We seem to clash on a few threads.


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## ek02 (May 8, 2012)

The motor looks pretty high, and if you are loosing water pressure it probably is too high. Try dropping it to the top holes, unless it's already resting on the transom. can't tell from the photo. A jack plate mounted lower on the transom may be the answer. If expense is an issue, a BOB's Machine manual plate is not too expensive. Having to run with the tabs that far down is not normal. They should only be needed to level the boat or put the bow down in a chop. Also a stainless prop with some cup in it will help, or have the aluminum prop cupped. Hope you get the problem solved.


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## Salt of the Water (Feb 26, 2018)

The motor is already resting on the transom and the antiventilation plate is even with the bottom of the hull. That picture is with the motor tilted up so its deceiving.

I know the boat is stern heavy (tiller motor + fuel), which is why a jack plate was lowest on my list. I'd prefer not to move weight further back if I have other options.

I'm working on getting some weight into the bow (trolling motor batteries), but not sure that will do much for turbulence off the tabs.


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## permitchaser (Aug 26, 2013)

Just me but those tabs look close to the motor. If your motor is over heating it's not getting enough water. So what's causing that. Those tabs also look big/wide for that boat. I'd take it back and let them fix it


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## Snookdaddy (Jan 5, 2008)

That's a Panga style hull, correct? That hull was made heavy duty and to run efficiently with low horsepower outboards and are in use throughout the world in some of the poorest countries in the world. I'm fairly certain that Yamaha helped design the original hull.. 

My point is... I just don't think that hull was designed to benefit from trim tabs.. The newer, lighter American made hulls may benefit, but I doubt this hull will.. 

Personally, I would seriously consider removing the tabs and moving on about your business..


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## Salt of the Water (Feb 26, 2018)

permitchaser said:


> I'd take it back and let them fix it


The joys of rigging your own skiff, no one to take it back to.



Snookdaddy said:


> That's a Panga style hull, correct? That hull was made heavy duty and to run efficiently with low horsepower outboards and are in use throughout the world in some of the poorest countries in the world. I'm fairly certain that Yamaha helped design the original hull..
> 
> My point is... I just don't think that hull was designed to benefit from trim tabs.. The newer, lighter American made hulls may benefit, but I doubt this hull will..


Yes it is a central American panga, but you have the weights backwards. The American built boats are heavier and usually wider.

I don't agree that there's no benefit from the tabs. I can already tell the boat is running better (plane at lower speeds, and better hole shot). Just looking for pointers on minimizing the knock on effects.


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## free88 (Apr 18, 2017)

I am not super familiar with these boats. I have seen a few in my area, but not in detail. If trim tabs could be installed from the factory, what size would they install? To me, 12Wx9L seems (and looks) huge for that boat. I am betting they are causing too much stern lift for the current height/placement of the outboard. 

For issue #1, well, you could just not use more than half trim tab. I know, I am captain obvious, and I deserve a medal. But, seriously, just don't use more than half trim tab. If you just have too much trim tabs (and no other issue), well, this is how you solve that problem.

For issue#2, if that is with zero clicks of trim tab, then yes, your outboard is too high. However, that would have already been happening even before you had trim tabs (if these trim tabs are installed correctly). If it was not happening before trim tabs and you have this issue now with zero clicks of trim tab, then I suspect that the trim tabs are too wide and/or mounted too inboard. They are disrupting the flow of water in the vicinity of the pickup enough to now be causing you a problem. Moving the trim tabs more outboard could be the answer, but that will not easy and clean. You could try to move the outboard down. You did say you are already full down on the transom, so no luck there. You will have to research for just the right jackplate that will allow you to drop this outboard. Alternatively, you could try fancy props and fins first. I am not as convinced as others in four bade, cupped, etc., props being the answer. But, some people do swear by them. I like the fins even less, especially for larger outboards. But, again, some people do swear by them.


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## jmrodandgun (Sep 20, 2013)

Put the tabs in full retract, then put a level on them. I bet the starting position of your tabs are too low. The stroke on the actuators isn't as much as you probably think. A few degrees in the wrong direction can give you too much lift.


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## el9surf (Dec 23, 2008)

This might be a dumb question, but are you adjusting the motor trim and the tabs as you're running? I'm assuming you've tried backing off the tabs and trimming the motor down once your on plane.

A 4 blade prop should help with the ventilation in turns. If you're limited on adjustments a compression plate might help keep some water around the intake.

Those tabs look awfully big for that narrow of a hull. They may be providing unwanted Stern lift even when they're raised fully up, which may be causing the water starvation on the motor.


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## Salt of the Water (Feb 26, 2018)

I've got 9x9 tabs in the mail. I did some more research into the Lenco installation instructions and remembered I ended up not going as far outboard as I could because that would have made the tabs fall on a strake which they recommend avoiding. 

I'll install the new tabs further outboard (1" from the edge), even if it means I end up closer to a strake than lenco recommends.

If smaller tabs outboard doesn't fix things then I'll look at a bracket or jack-plate to let me get the motor down lower.



el9surf said:


> This might be a dumb question, but are you adjusting the motor trim and the tabs as you're running? I'm assuming you've tried backing off the tabs and trimming the motor down once your on plane.


Motor is trimmed all the way in. The transom is flat so I don't really have any negative trim to be able to tuck the motor.

I can run the boat ok with less tab. At higher speeds it gets on plane and flattens out ok. At lower speeds I'm still more bow up than I'd like.


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## devrep (Feb 22, 2009)

on plane wide open your anti cavitation plate should just be visible at the surface. I wonder if smart tabs would be a better option in this case?


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## Vertigo (Jun 3, 2012)

I'll jump in here. That boat was never designed for tabs nor should it need them. It's got a high bow, so yes it's going to be hard to see over at slow speeds. The hull was also designed for commercial fishing, which means that it can carry a lot of weight forward. I'd remove the tabs, check the motor height (cav plate about 1" above keel), and move weight forward.

BTW, a jack plate isn't going to allow you to get the motor much lower. The transom will interfere.


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## Salt of the Water (Feb 26, 2018)

Follow up: got narrower tabs installed wider on the transom. Performance is much better and I can tab the bow further down without ventilation / cavitation issues.


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## Smackdaddy53 (Dec 31, 2012)

el9surf said:


> This might be a dumb question, but are you adjusting the motor trim and the tabs as you're running? I'm assuming you've tried backing off the tabs and trimming the motor down once your on plane.
> 
> A 4 blade prop should help with the ventilation in turns. If you're limited on adjustments a compression plate might help keep some water around the intake.
> 
> Those tabs look awfully big for that narrow of a hull. They may be providing unwanted Stern lift even when they're raised fully up, which may be causing the water starvation on the motor.


It is a very common misconception that a 4 blade prop is superior to a three blade in the cavitation in turns department. Another one is people tend to believe a 3 blade prop is only meant for speed and a 4 blade will always give better hole shot. Neither are true all the time, some boats run faster with a 4 blade and get the best hole shot with a 3. 
Glad you got it figured out!


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## el9surf (Dec 23, 2008)

Smackdaddy53 said:


> It is a very common misconception that a 4 blade prop is superior to a three blade in the cavitation in turns department. Another one is people tend to believe a 3 blade prop is only meant for speed and a 4 blade will always give better hole shot. Neither are true all the time, some boats run faster with a 4 blade and get the best hole shot with a 3.
> Glad you got it figured out!



Looks like I hit the nail on the head in my list of possible causes. Narrower tabs and problem solved. In general a 4 blade should provide better hole shot, better handling and a lower top speed. I'm sure there are some exceptions due to various factors such as hull design, but as a rule of thumb I don't think anyone is installing a 4 blade with the hopes of picking up speed over a properly pitched 3 blade.


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## Smackdaddy53 (Dec 31, 2012)

el9surf said:


> Looks like I hit the nail on the head in my list of possible causes. Narrower tabs and problem solved. In general a 4 blade should provide better hole shot, better handling and a lower top speed. I'm sure there are some exceptions due to various factors such as hull design, but as a rule of thumb I don't think anyone is installing a 4 blade with the hopes of picking up speed over a properly pitched 3 blade.


You da man


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## Salt of the Water (Feb 26, 2018)

Another follow up post in-case anyone else has similar issues in the future.


I’ve run the narrower tabs for a while and haven’t come across any drawbacks. I can use heavy tab and keep on plane at about half throttle. The overheat and cavitation issues never came back.

I finally got around to adding a stainless prop, and I’ve run it a few times now. Top speed is about the same as the aluminum prop but the stainless prop gets on plane much better.

As long as the motor isn’t bumping bottom when trimmed in all the way, I can idle up to about 5mph, drop the tabs and go full throttle to hop up on plane. When I tried that move with the aluminum prop, the stern would squat and I’d start bumping bottom, making me have to idle further into deeper water.


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