# Using tabs to stop porpoising ?



## mtoddsolomon (Mar 25, 2015)

My boat does the same without tabs, a couple taps of the tabs and boom i'm running solid again. I say get them, you won't regret it.


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## ADicus (Feb 15, 2013)

Definitely worth it! make a boat run completely different!


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## Swe (Apr 19, 2017)

Yea think I'm going to just wondering if others had same issue. My concern was I tab down and porpoising will stop but may end up with bow down condition. So you able to stop porpoising but still maintain a little bow lift with combo of tabs and engine trim?


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## Swe (Apr 19, 2017)

ADicus said:


> Definitely worth it! make a boat run completely different!


Had on previous boats never touched them , went without on this boat now I think I need them.. lol


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## predacious (Sep 1, 2016)

Carolina skiff ??


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## ADicus (Feb 15, 2013)

Even if the boat didn't porpoise it's still one of the best addictions to fine run running in any conditions! They are expensive but will drastically help!!


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## LowHydrogen (Dec 31, 2015)

Without writing a book, a lot of porpoising comes from having the motor mounted too low and the cavitation (anti ventilation plate) enters the water at a low angle raises the bow till it gets too heavy the bow then drops......the cycle repeats. Even if you're going to add tabs I'd be willing to bet the motor is mounted too low. Cav plate should be 1/2"-1" or more above center-line running surface (depending on how far back your motor sits from the transom). Keep raising it till it blows out in hard turns then drop down one hole. If it's still bad enough to be a problem...then add the tabs.
Many builders, and others mount the motors too low IMO. Oh yeah if that's not enough motivation, you'll likely pick up a couple MPH too


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## crboggs (Mar 30, 2015)

You should be able to reduce porpoising with correct motor trim and then fine tune further with trim tabs based on conditions like wind, chop, etc.


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## predacious (Sep 1, 2016)

LowHydrogen said:


> Without writing a book, a lot of porpoising comes from having the motor mounted too low and the cavitation (anti ventilation plate) enters the water at a low angle raises the bow till it gets too heavy the bow then drops......the cycle repeats. Even if you're going to add tabs I'd be willing to bet the motor is mounted too low. Cav plate should be 1/2"-1" or more above center-line running surface (depending on how far back your motor sits from the transom). Keep raising it till it blows out in hard turns then drop down one hole. If it's still bad enough to be a problem...then add the tabs.
> Many builders, and others mount the motors too low IMO. Oh yeah if that's not enough motivation, you'll likely pick up a couple MPH too



this doesn't hold true for all boats - the part concerning antiventilation plates/motor height


porpoising is also caused by too much weight aft,too much positive trim,hook in the hull and bottom flexing


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## Smackdaddy53 (Dec 31, 2012)

Yes, trim tabs will knock down the porpoising issue and you can still adjust motor trim as well. My boat runs it's fastest with the motor trimmed out until it porpoises then I add just enough tab to kill it and she skates along perfectly. In addition to this tabs have many other uses like aiding holeshot and attitude when quartering chop.


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## SomaliPirate (Feb 5, 2016)

My 17T will start to porpoise a little when it's fully trimmed out. I just touch the tabs for a second and she settles right down.


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## Swe (Apr 19, 2017)

Thanks guys going to get those orders and install only thing I haven't tried hopefully it works .


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## LowHydrogen (Dec 31, 2015)

predacious said:


> this doesn't hold true for all boats - the part concerning antiventilation plates/motor height
> 
> 
> porpoising is also caused by too much weight aft,too much positive trim,hook in the hull and bottom flexing


You're right it doesn't hold true for all boats, but in my experience it has held true for most skiffs. If the motor is set back from the transom a long way, or he's running a pocket drive/tunnel etc it could be higher, but the op says he's running a flat bottom. The other things you mention are also very true, but the op said he's shifted weight around, tried different props, and has no hull issue. Either way, for me, raising it till it blows out on hole shot, or sharp turns then dropping down, gave best performance. That avatar is hilarious btw, I think I've had that guy work on a motor of mine in the past lol.

@Swe tabs are definitely nice, universal mania had a lenco kit for $450 a while back. Good luck and report back on how it goes.


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## fjmaverick (Sep 18, 2015)

Balancing a boat is more important in my opinion. My dads 21 contender used to porpoise unless loaded down. It liked a full tank of gas (90 gallons) and a load of ice in the fish locker.


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## Swe (Apr 19, 2017)

LowHydrogen said:


> You're right it doesn't hold true for all boats, but in my experience it has held true for most skiffs. If the motor is set back from the transom a long way, or he's running a pocket drive/tunnel etc it could be higher, but the op says he's running a flat bottom. The other things you mention are also very true, but the op said he's shifted weight around, tried different props, and has no hull issue. Either way, for me, raising it till it blows out on hole shot, or sharp turns then dropping down, gave best performance. That avatar is hilarious btw, I think I've had that guy work on a motor of mine in the past lol.
> 
> @Swe tabs are definitely nice, universal mania had a lenco kit for $450 a while back. Good luck and report back on how it goes.


Yes I saw those , any one buy from them before ?


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## fjmaverick (Sep 18, 2015)

Yamaha just bought Bennett Marine


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## crboggs (Mar 30, 2015)

Smackdaddy53 said:


> Yes, trim tabs will knock down the porpoising issue and you can still adjust motor trim as well. *My boat runs it's fastest with the motor trimmed out until it porpoises then I add just enough tab to kill it and she skates along perfectly.* In addition to this tabs have many other uses like aiding holeshot and attitude when quartering chop.


This. I start with the motor all the way down...then raise the motor bit by bit until I begin to porpoise slightly...then I lower it in small increments until the porpoising stops. That should be your sweet spot for speed with the minimal amount of hull in the water. And once you get to this point, you can adjust with the trim tabs based on conditions or etc.


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## LowHydrogen (Dec 31, 2015)

Swe said:


> Yes I saw those , any one buy from them before ?


I bought a switch and control box kit from them a few weeks ago. They're legit. Fast shipping and the product was perfect. Can't speak to a whole tab kit, but I can't imagine they're any different.


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## Smackdaddy53 (Dec 31, 2012)

crboggs said:


> This. I start with the motor all the way down...then raise the motor bit by bit until I begin to porpoise slightly...then I lower it in small increments until the porpoising stops. That should be your sweet spot for speed with the minimal amount of hull in the water. And once you get to this point, you can adjust with the trim tabs based on conditions or etc.


Here's what 33mph looks like when I run across the bay. Let her eat!


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## No Bait / Lures Only (Apr 10, 2011)

I have owned 3 skiffs, only the Spear glade x flat bottom style has trim tabs, I rarely use them except in a chop. The 2 v bottom Hoog and Shipoke don't have tabs and don't need them, as neither porpoise at any speed or trim


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## LowHydrogen (Dec 31, 2015)

Smackdaddy53 said:


> Here's what 33mph looks like when I run across the bay. Let her eat!
> View attachment 13464


When did you get a surface drive? LMAO


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## Nickhoog (Nov 28, 2015)

I put these on my Scout 16' work great. Run and set for max performance, even played around with different actuators.

http://nauticusinc.com/


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## Nickhoog (Nov 28, 2015)

I bought the Smart Tabs.


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## Mike C (Feb 27, 2017)

Smackdaddy53 said:


> Here's what 33mph looks like when I run across the bay. Let her eat!
> View attachment 13464


SmackDaddy,
Looks like you're running a jackplate.
Re, your boat:
Is that a HPX or Hewes Tailfisher? 
I have an '08 Tailfisher with a 60hp Yamaha. It has the big lower unit. 
Running a 4 blade PT stern lifting prop. It is loaded heavy and will be going on a diet as soon as the weather cools. 

I'm aware that 2 strokes give higher top end speed. 
Are you getting that speed with a 60 or 70hp?
What prop do you run?


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## Swe (Apr 19, 2017)

Nickhoog said:


> I bought the Smart Tabs.


No smart tabs , hanging down kills the draft when poling


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## coconutgroves (Sep 23, 2013)

Swe said:


> No smart tabs , hanging down kills the draft when poling


What boat and size motor do you have? Didn't see that above and is important to know. What hole is the motor hung at?


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## Swe (Apr 19, 2017)

coconutgroves said:


> What boat and size motor do you have? Didn't see that above and is important to know. What hole is the motor hung at?


Thanks appreciate the help but left that out on purpose as I didn't want to go back and forth people telling me things I know or already checked . My question was specific to tab use with trim of engine . Just wanted input on use of tabs and was it possible to tab down and trim engine up and not create a nose dive situation and maintain a slight bow rise?


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## Smackdaddy53 (Dec 31, 2012)

Swe said:


> Thanks appreciate the help but left that out on purpose as I didn't want to go back and forth people telling me things I know or already checked . My question was specific to tab use with trim of engine . Just wanted input on use of tabs and was it possible to tab down and trim engine up and not create a nose dive situation and maintain a slight bow rise?


Yes it is very possible to attain that with tabs, I do it all the time.


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## Smackdaddy53 (Dec 31, 2012)

Mike C said:


> SmackDaddy,
> Looks like you're running a jackplate.
> Re, your boat:
> Is that a HPX or Hewes Tailfisher?
> ...


Hull #10 HPX Tunnel
70TLRZ
3 blade XXX cup 14" diameter 14 pitch Jack Foreman Custom Holeshot


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## Mike C (Feb 27, 2017)

Awesome, 
Thanks for the info
Once I get some weight off my boat, I'll reassess my prop and might go that direction. 
May have a bit more cup added to mine until then. 
Is the jack plate worth adding?


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## Mike C (Feb 27, 2017)

Awesome, 
Thanks for the info
Once I get some weight off my boat, I'll reassess my prop and might go that direction. 
May have a bit more cup added to mine until then. 
Is the jack plate worth adding?


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## Rick D (Nov 14, 2011)

Smackdaddy53 said:


> Yes, trim tabs will knock down the porpoising issue and you can still adjust motor trim as well. My boat runs it's fastest with the motor trimmed out until it porpoises then I add just enough tab to kill it and she skates along perfectly. In addition to this tabs have many other uses like aiding holeshot and attitude when quartering chop.


Same on my East Cape Lostmen. Wouldn't run without them


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## Rick D (Nov 14, 2011)

Mike C said:


> Awesome,
> Thanks for the info
> Once I get some weight off my boat, I'll reassess my prop and might go that direction.
> May have a bit more cup added to mine until then.
> Is the jack plate worth adding?


From my experience the jack plate and cupped prop are a must if you want to run skinny. I can run my Lostmen at full trim on the jack plate and still have water pressure to the engine (I also have a Bob's nose cone on my motor) and maintain thrust. At full trim on the jack plate with the right amount of engine trim and tab I can run with the bottom of the bullet even to the bottom of the hull. Great for getting over shallow sand bars on negative tides.


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## Smackdaddy53 (Dec 31, 2012)

Rick D said:


> From my experience the jack plate and cupped prop are a must if you want to run skinny. I can run my Lostmen at full trim on the jack plate and still have water pressure to the engine (I also have a Bob's nose cone on my motor) and maintain thrust. At full trim on the jack plate with the right amount of engine trim and tab I can run with the bottom of the bullet even to the bottom of the hull. Great for getting over shallow sand bars on negative tides.


Sand blasting the lower unit and installing the nosecone soon!


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## coconutgroves (Sep 23, 2013)

Swe said:


> Thanks appreciate the help but left that out on purpose as I didn't want to go back and forth people telling me things I know or already checked . My question was specific to tab use with trim of engine . Just wanted input on use of tabs and was it possible to tab down and trim engine up and not create a nose dive situation and maintain a slight bow rise?


So do want first hand feedback from people that have the same boat and motor, or do you want to understand hydrodynamics and nautical engineering? Some setups do not need tabs at all, but can have problems due to weight imbalance. Posting specifics gets to the point faster, but hey, that's just me.


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## Swe (Apr 19, 2017)

Update ... So all done with install and a quick test today in local canal . Seems to have solved the issue was able to trim up and tab down to stop the bouncing . Whole boat seems to ride higher in the water and water sprays out much further back on hull now. So far so good will play with more on next fishing trip ..


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## Guest (Aug 9, 2017)

I understand that trim tabs would allow me to trim the motor up until I porpoise, then I can use the tabs to stable out / smooth out the boat. If I can use the tabs to smooth out the boat's ride, that would mean that I'd be able to trim the motor up higher than I normally would. Is it correct to conclude that trim tabs will allow me to run a bit shallower too?


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## Guest (Aug 9, 2017)

A few questions: What length boat did you install these tabs on? How much work was involved? What did they cost? Where did you buy them?


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## Swe (Apr 19, 2017)

Josh Stewart said:


> A few questions: What length boat did you install these tabs on? How much work was involved? What did they cost? Where did you buy them?


Boat 16'6" few hours to install just drilling holes and screwing in , online Universal Mania was cheapest price I found .


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## Guest (Aug 9, 2017)

Thank you very much!


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