trim settings on plane

[torcano]

When a boat leans to the right while on plane what is the proper method of correcting it using the trim tabs? Press the bottom side of the right trim rocker switch (bow up)? If the trim tabs are already in the full up position, how can this help? I was told to start out each trip with trim tabs set in the full bow up position. Is this correct? If the boat leans to the right, do you ever hit the left trim tab (top of rocker switch) to lower the bow on the left?

 

[marine4003]

Re: trim settings on plane

Ok,Capt ,first a little tab lesson - tabs, when activated in the "bow down" position cause the tabs to extend down into the water,thereby causing the bow to fall, this position is used at starting from a stop and applying throttle...when the boat has achieved "plane" the bow should be level with the transom,or slightly higher...by now its a smooth ride,1/3 of the hull(rear) is moving thru the water smoothly. If the boat is leaning to port or starboard,the tabs can be further lowered to compensate for this action..just remember..boat leans right-use left trim button....boat leans left...use right, The only way to figure out how much tab is by experimenting,you dont need to press and hold..just push it quick..wait to see results..go from there. Your not gonna hurt anything,play with it till you get comfortable...Then we can discuss, Tabs & Trim.

 

[torcano]

Re: trim settings on plane

Thanks. It seems like there is some diversity of opinion and how to use trim tabs (at least at my marina). I think experimenting on my own makes sense. It also makes sense to me that if the boat is tilting to starboard it means the port side of the bow is up and needs to be lowered on that side. I'll see how my boat responds. I was originally told to apply "bow down" to the side the boat was leaning to and it clearly made things worse.

 

[Boatist]

Re: trim settings on plane

The best way is to just go out with no place to go and play with it.

In you first question boat on plane and leans to the right. If both tabs are all the way up then you have only one choice, hit the top of the left switch and bring the port side down to match. Normally if both tabs are all the way up the boat should be pretty level unless you have cross winds. If not then you may want to figure out why it leans and correct that problem.

If both tabs are part way down and the boat leans to starboard and you want to level then you must first ask yourself if you want the bow higher or lower. If you would like it lower then you again would hit the top of the left switch and lower the port side. If you want the bow higher then you would hit the bottom of the right switch and allow the starboard side to rise.

Once you get it level side to side then you decide do I want the bow higher for more speed and fuel mileage or do I want the bow lower to allow the sharpest part of the bow to start cutting the wave and smooth out the ride.

To lower the bow you would hit the top of both switches or to raise you would hit the bottom of both switches to raise the bow.

After a while it just a natural thing and you do not even think about it.
Also after a while you will just look at the water conditions and have a good idea how you want to trim and you can pre adjust before you come up on plane.

The way I normally adust mine is first I think about where we are headed and look at the water.
If we are going a long way then I will be running at my best fuel mileage speed in the 20 to 25 mile per hour range. With no trim at all I will make sure everyone is seated and we are out of the 5 mile per hour zone then apply full throttle and let the boat hope up on plane. As I get near my target speed I will start pulling back the throttle and set my speed. Now I see how the ride is and adjust the bow down to get the ride I want. Last thing I do is without touching the throttle or trim I adjust the motor trim a little at a time to get the best speed. You need to do this slowly to allow the boat speed to change. When you find your best speed you also have the best fuel mileage.

As conditions change you may want to readjust your bow height for better ride.

Also in general after you reach planing speed the higher the bow is the better the fuel mileage. Spray will be coming off the back 1/3 of the boat at most.

Most planning hulls best mileage is just at a fast idle. With no trim tabs and the motor trim in the center increase the throttle a little at a time. Your bow will be pushing water, as you increase a little at a time the bow will start to clime up on your own bow wave. Keep increasing a little at a time but watch ahead and when you get in the 18 to 25 mile range on most boats the boat will start to overtake the bow wave. Once you do the bow will come down on the water and the speed will increase on it own a lot. At this point you are on plane bump the throttle just a little more to make sure you on a clean plane and this will usually be you second best fuel mileage. I call this the boat natural planing speed and it slightly different for every boat and every load you have on the boat. The boat is kinda of surfing down it own Bow wave and you can here the load on the motor decrease while the speed increases. From this point as you increase the throttle each time you decrease your fuel mileage. Full throttle will be your second worse fule mileage. The worst fuel mileage was back when the bow was at it highest trying to clime over your bow wave.

Another thing I think is a good thing to do is to slow down a little at a time and see what speed the boat comes off plane.

With modern fuel injected motor with Computer to adjust the amount of fuel injected the best mileage speed can very but that speed where the boat reaches a clean speed will remain a point where there is not as much load on the motor and it uses less fuel.

In normal practice you would do niether of these exercizes but it is good to know where these natural speed are for your boat.
Instead you would look at the Seas as you leave the 5 mile per hour zone, check your fuel, Check you Temperature, Check you Oil pressure, Make sure the fenders are in and no line hanging, Adjust trim tabs to where you guess will be best, Make sure everyone is seated and go full throttle until you reach planing speed. Fine tune your ride with the trim tabs, set your speed and then fine tune your motor trim for mileage on long runs.

With hydraulic trim tabs one thing you do not want to do is to hit the top of one switch and the bottom of the other switch. The reason is when you hit a switch too thing happen first the Hydraulic pump turn on. When you hit the top of the switch it pumps fluid into you cylinders. When you hit the bottom of the switch the pump runs backward and pumps fluid out of the trim cylinders. Of course it can not run foward and backwards at the same time. Also when you hit a switch it pulls a solenoid to allow fulid to go into the correct cylinder. You can pump into both by hitting the top of both switches.
You can pump out of both Cylinders by hitting the bottom of both switches.

Have fun with it.

 

[torcano]

Re: trim settings on plane

Thanks again Boatist. Your explanation makes sense to me and I always prefer to understand why I am doing something as opposed to just doing it because I was instructed to do it. We are having great weather this holiday weekend here in the northeast. I plan to do spend a lot of time on the water learning how to use my trim tabs.

 

[tashasdaddy]

Re: trim settings on plane

every boat, and motor set up, reacts differently. you have to experiment, to find the sweet spot with your particular set up. the setting of trim tabs, tirm of the motor, load in the boat. all effect the way a boat handles. there is no set rules or reasons. no 2 boats are exactly alike.

 

[KnottyBuoyz]

Re: trim settings on plane

There's also the option to install an "Automatic Tab Control" if your setup is a Bennett.

http://www.bennetttrimtabs.com/autotab.htm

Pretty much makes the whole process foolproof. Those I've spoken to that have installed the ATC love it. I opted for the electronic trim tab control so I could see on the display where my tabs were. It also auto retracts the tabs when you turn the key off.

 

[torcano]

Re: trim settings on plane

Rick, I was considering the Bennett ATC but they are just shy of $400 and I'm not sure I wan't to spend that much right now. I have Bennett hydraulics on my boat. Is there a guage that I can buy to tell me the position of the tabs as you referenced?

 

[KnottyBuoyz]

Re: trim settings on plane

Bennett has a couple of indicators and switches. One is called the "trimdicator" or "trim position indicator" and the other is the Electronic Tab Control, that's what I bought. Plug & Play.

You can find the ATC's on e-Bay for $250

 

[torcano]

Re: trim settings on plane

Thanks. I'll check it out.

 

[Boatist]

Re: trim settings on plane

I would not put on automatic controls even if they were free.
There no two days that I want the boat adjusted the same. Running into a big head Sea I use a lot of trim to keep the bow cutting waves, when I head in it is unsafe to have any trim with a big following sea.

Also when turn the key off they retract. I often use trim tabs while anchored.
When fishing on day with light current and windy I put the trim tabs down. It helps hold the boat straight and I do not have to put out a sea anchor or bucket.

 

[torcano]

Re: trim settings on plane

I can understand your point. It's like driving an automatic transmission. I only drive manual transmissions because I prefer to shift gears to suit the driving conditions and the way I feel that day. I like the idea of knowing where the trims are at any given time. I always start out by retracting both tabs but the idea of an indicator sounds good, assuming they are accurate.

 

[KnottyBuoyz]

Re: trim settings on plane

I always start out by retracting both tabs but the idea of an indicator sounds good, assuming they are accurate.

There's a lil' proceedure in the setup to calibrate the tabs. It's dead accurate after that!

The ATC can be shut off if conditions warrant it. Those I've talked to that have it love it. For 90% of your running it saves a lot of tweaking the tabs which is something I personally don't enjoy.