Running with tabs: primer

[rangerdog]

Lots of discussions adout tabs but we really have not talked about tab operation. I'd like to hear some "dos" and "don'ts" from the more experienced pilots.

For example: Do you deploy your tabs at, during, or before acceleration?

What about following seas? Head seas? I know how to use them for cross chop and weight distribution but I have never "run" an inlet, etc.

What say you, old salts?

 

[JC]

Lenco Trim Tabs
Trim Tab Operation

-Head Sea-
Head Sea — Lower both tabs slightly by pressing Bow Down on both sides. this brings bow down while maintaining speed. This adjustment allows the hull of the boat to absorb the impact of the waves, resulting in a more efficient and smoother ride.

-Following Sea-
Following Sea — Make sure the tabs are fully retracted by pressing Bow Up on both sides. This brings both tabs to a fully retracted position decreasing lift in the stern, allowing the bow to rise. If tabs are deployed, the bow may dig.

-Windy Chop-
Windy Chop — To raise the windward side of the boat press Bow Up on that side. If this is not sufficient, press Bow Down on the leeward side of the boat. Do not over trim when attempting this. This allows the windward side of the boat to rise and minimizes spray.

-Shallow Water -
Hole Shot
Shallow Water/Hole Shot — Lower both tabs completely down by pressing Bow Down on both sides. This provides lift in the stern of the boat and keeps the bow down. As you throttle up and speed increases, raise tabs by pressing Bow Up on both sides.

-Uneven Load-
If one side of the boat is higher than the other while running, press Bow Down on the switch on that side. This lowers the tab on the listing side (low side) to bring the boat level.


-Porpoising-
Porpoising — To stop porpoising, press Bow Down on both sides of the switch. The tabs need only to be deployed slightly to correct this adverse situation.

-Safety-
While the boat is underway, do not move one tab up or down significantly; this may cause listing.
While at higher speeds, do not over trim. This causes the bow to lower quickly, resulting in a reduction of speed and may cause the boat to veer.
When in following seas or when running an inlet, the tabs should be fully retracted. This allows for optimal performance.
While operating trim tabs, use caution. Improper use of trim tabs may cause accidents and/or injury.

 

[sslocum]

I have a new Parker 2120 with factory Trim tabs. I am trying to figure out the best way to use them. The two switches are next to each other but the port switch operates the stbd tab and the stbd switch operates the port tab. Is this correct or were they wired wrong.

 

[Outta Here]

I have a new Parker 2120 with factory Trim tabs. I am trying to figure out the best way to use them. The two switches are next to each other but the port switch operates the stbd tab and the stbd switch operates the port tab. Is this correct or were they wired wrong.

here's the deal...mash top of starboard rocker, it pushes down port tab. This gives you "starboard bow down". There's a criss-cross action as the boat rocks back and forth.

 

[andertonm]

JC's summary is great - add it to the textbook.

It should be noted that use of the tabs steers the boat - putting the port trim tab down makes the boat go port and vice versa - just like dragging an oar in the water. Really confuses an autopilot.

 

[Megabyte]

Do you deploy your tabs at, during, or before acceleration?

What about following seas? Head seas?

I agree with most of what Lenco publishes, but I do differ with them on the use during hole shot...

When I'm coming out of my creek at <6kts, one of the things I double check in my 'pre-plane' prep is to make sure that my tabs are fully retracted. It's something I generally do when going back to my slip, but I always double-check on the way out as well.

Once I clear the 6kt area and I'm ready to power up, I'll run the throttle up to, and steady at about 4200 rpm.
As the bow rises and stablizes, I start the "two finger tap" and go bow-down until the bow just starts to settle.

At that point I let the bow settle and the stern raise, giving the tabs subtle adjustments as needed until I'm at the attitude that I want.
As I enter the Bay, I adjust the tabs to the conditions as I find them, and enjoy the ride.

It doesn't take much for a set of 24x9 flippers to give me the attitude I want.

Following seas... tabs fully retracted.

Head seas... just enough tab, combined with judicious use of throttle to give me a good ride. :wink:

 

[TOPFROG]

One little added note here after reading much theory on the effective use of trim tabs.....Tabs to set the plane of the boat, then trim the prop to make the prop push parallel to the water's surface - getting the most MPH per RPM at the proper plane is the normal objective That goes out the window in rough seas though - a better ride being the objective then.

 

[sslocum]

Thanks for the information that clears it up for me. Now it is just practice and time on the water. Too bad that job thing gets in the way.

 

[channel_surfer]

There's really no reason at all to take a holeshot with the tabs up. Tabs down will always get you up on plane and moving faster. Once you pop up on plane you can raise them to get the ride / efficiency you want.

 

[rplas48]

All good advice. I have the 2120SC , F150 with stock Lenco tabs and one thing I noticed is that running in calm water or a light chop is that the tabs are not really needed and if used will reduce RPM by 100 to 200 with a drop in speed. This is with the engine trimed at slightly higher than 4 on the gauge.

Ray

 

[Burtona]

I have a new Parker 2120 with factory Trim tabs. I am trying to figure out the best way to use them. The two switches are next to each other but the port switch operates the stbd tab and the stbd switch operates the port tab. Is this correct or were they wired wrong.

My 21 SE was wired with cross tab controls also. Didn't make sense to me and I didn't like it so I changed mine so that the starboard switch operates the starbord tab. Cross controls were just too confusing for my old brain to deal with.

 

[esfishdoc]

I think the key to using tabs is to constantly play with them and explore the impact they have on the boat.

I have a fuel monitor and that adds another dimension to the usefulness of the tabs.

When I'm operating my boat I'm trimmed in one of two ways: 1. comfort 2. economy. Of course I now think of #3: a blend of 1 and 2. When I’m fighting a 25 mph head wind and a 3 foot tight chop on the bay it’s all about comfort. When I’m running offshore for 3 hours straight in 2 to 3 foot swells it’s all about economy.

The standard configuration of the switches is to control the boat in a logical way. Pressing the top right switch makes the right top/front of the boat go down. If you change the switches around to suit you that's fine.... but you'll have problems running other boats once you wire your brain with your switch configuration. Also, if I hop in your boat things will be backwards for me.

I'll go a bit across the grain and say that some trim in a following sea is just fine and even desirable. For example a one foot chop is not going to present any threat to safety. Even with a 2 foot following sea the boat may perform better with some tab deployment. This of course depends on the length of your boat and weight distribution. I would agree that anything 3 foot or greater you will not want any tabs deployed in a following sea. The steepness of the wave is of greater concern than the height. Out on the ocean with a 3 foot following swell I’ll have the tabs down some. A windy day on the bay with a 3 foot tight chop at my stern they are all the way up!

It is real easy to learn how to get the most comfortable ride using your trim tabs. You can feel the difference. What is not so easy is getting the best economy out of your tabs.

I've found that there are a few counter-intuitive idiosyncratic quirks when it comes to economy. I’ll propose here that if you do not have a fuel monitoring system, you could be losing .5 mpg all day long and never know it. Needless to say a fuel monitoring system will change the way you operate the boat and pay for itself well within the first 1000 miles of running.

I’m approaching 500 hours on my motor and I still rely on the fuel monitor to tweak out those last couple of tenths on my mpg readings. Winds, currents, waves, weight of passengers and their placement and fuel load all will alter this. Without the gauge there is no way to know if you are trimmed at max efficiency. There is always a speed at which the hull is at its peak efficiency and it isn’t as slow as you might think. The economy curve is not linear. There is a peak at very slow speeds and this starts to dive steeply as hull speed is reached and continues to go down until plane is reached.
Then it starts to improve. It will improve up to a point depending on all those variables mentioned above and then drop off fast once it is exceeded. When the water is flat calm and I’ve got an average load it is more economical for me to run at 30 mph than it is 25. In almost all situations the worst economy is with the tabs all the way up (and of course all the way down). You might think that as soon as the tabs start going down and deflecting water you would lose economy…. And that would be wrong. The max efficiency of the hull can only be achieved with tabs. The trim of the motor does not have enough influence on hull attitude to get to max efficiency.

Every thing I’ve just spouted out is anecdotal information based on my observations. I believe it is all true….. but I’ve been wrong before.

Richard