Triming your boat??

steriltech

steriltech

Member
Jun 1, 2010
96
New Jersey
Boat Info
1998 searay sundancer DA
Engines
4.3 engines..
Ok just wanted ask for a smooth take off were should your engines be positoned along with your trim tabbs? Also were should your trim gauges be pointing up down,or center..:smt009 I have 2 trim gauges the are stuck on up I'll have to check them to see if they were disconnnected and not put back? :smt101 thanks all....
 
Engine i/o should be tucked all the way down at start up. Tabs should also be all the way down. As you add power, tab up a little to bring the hull up. Adjust port and starboard tabs as necessary to get rid of any lean into the wind. Tab down a bit if you are taking waves heavily of the nose. Tab up a bit on the lee side of a quartering sea on the nose or a following sea to trim the boat to comfortable running angle. I was never much of a fan of messing with outdrive trim. Most trim them up so high that they fly a rooster tail. When you do that you are placing a great deal of stress on the u-joints and gimbal bearing. If money is no object, have at it.
 
In my older 300DA for take off, engines all the way down, tab's all the way down, Hit the throttles, 4 seconds later I am on plane. Now I give short burst to both tabs at the same time, until I have the bow where I want, boat seems to right best with hull making wake right under my seat. If heavy wind, off balanced load, I might have to give one or the other tab a quick tab (and then wait a few seconds for the boat to respond) to level it out, but that's rare for me.

If I am screaming across open water for an extended period, then I will bring the drives up a tiny bit, watch my speed and rpm's, when rpms go up without any increase or a decrease in speed, then I bring them back down a little. Again this is rare for me to even mess with. The switches are in the end of the throttles handles which are a PITA to get to when throttles are forward and it takes very little movement before I am past the sweet spot, so unless I am running Wide Open for a while just not worth the effort.

Based on the wording of your question I am guessing you are new to trim tabs, so I will give you a few tips I wish I had gotten when I got my first boat with them.

The buttons are just the opposite of what you think. Left button works right tab, pushing button up moves tab down. The reason for this is to make it easier for you to control the boat without having to think about what the tabs are doing, if your leaning to the right, you either press up on the left (bow down) or down on the right (bow up) to correct. Simply put you press the buttons up or down if you want that side of the bow to go up or down.

Make very small adjustments (never for than a 1 - 2 second burst) then wait a few seconds. The biggest mistake folks make with tabs is over adjusting, which can lead to some extreme conditions where the boat decides to take a sharp turn left or right because you have over adjusted one tab to much.

And last but not least, every boat is different and it also depends on wind/water conditions and the way you have boat loaded and passengers moving around. So you really have to just get out there and play with them until you get a feel for how your boat reacts.
 
Who are you and where did your Bulgarian twin go? :grin:

Good question. What size Sundancer are you running? You might want to edit the "boat" line in your profile to include the actual desgnation, like 260DA, 270DA, etc.. It matters for most of the questions you will ask in the future.

In my 260, I always start off with the trim tabs all the way up and the drive all the way down. I smoothly apply power until I get to about 3300-3500 RPM. After a couple of seconds I am on plane, but the attitude and speed of the boat will be all wrong. The bow is too high and the speed is too slow. Fuel burn is also too high. I start bringing the drive up a couple of bumps at a time. This will actually have the opposite effect of what it should (up drive trim normally = bow higher), the bow will start dropping and speed will increase. I keep bumping the up trim until the boat levels off side to side (or at least as close to level as its gonna get without using the trim tabs). At this point, I usually need to back off on the throttle as moving the drive to proper running position makes the engine speed up a good bit. Once the engine RPM and fuel burn look correct for the speed that I am running, I use a single trim tab to get the boat level. If in calm water, that's it. If the water is rough, I will use both trim tabs to lower the bow about 2-3", and tweak the drive trim for the best RPM and ride. If the bow is riding up waves and wakes and then slamming back down on the other side, I trim the drive up a little more to stop it by letting the drive lift the bow a little. If it feels like the boat is "leaping" off of the waves and wakes, then I give the drive trim a little down to stop it by letting the drive push the bow down a little.

You can try my method, but it might not be exactly correct for your boat. You just need to play around with it and get a feel for the boat. If it takes you 30 seconds to get on plane, try it again with a little down on both trim tabs. If bringing the drives up doesn't make much difference, try the tabs instead.

Oh, and don't use the drive trim gauges (once you get them working) as a "I gotta put the needle on that mark to get the boat running right" device. The correct drive position for the trip that you are on will vary with the load in the boat as well as wind and sea conditions. My gauge works most of the time, but I don't use it for anything but making sure that the drive trim is operating. The sound of the engine, RPM, fuel burn, and feel of the ride will tell you when you get it "right".

Michael
 
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Thanks for the replies! just knowing that the buttons on the left thoddle handle when pushing down causes the tabs to raise is new to me I was under the impression when you push down they go down not up?? :smt101 man I know is when I gunned it the boat aimed up and it felt like I had the breaks on...I was affraid to do anything after that as for the size of my boat it is a 1998 290da..:smt038
 
Hold the phone there, partner. The buttons on the throttles work the DRIVE trim, not the tabs. There should be a control panel on the dash with the tab controls. You might have 2 rocker switches, which pivot in the center allowing you to press the top to put the tab on the opposite side (left rocker works right tab, and vice-versa) down, or press the bottom to raise that tab. You might have 4 buttons instead of the 2 rocker switches. The top buttons lower the tabs, the bottoms raise them.

Look at the bow instead of thinking about which button or side of the rocker to press. If the boat is leaning to your right, then you need to lower the bow on the left side of the boat. Press the top of the left switch if you have rockers, or the top left button of the 4 button panel, and think of it as using your finger to push that side of the bow down. If you go too far and the boat starts leaning left, press the bottom of that rocker, or the bottom left button and think of it as lifting that side of the boat with your finger. To lower the entire bow when you need to smooth out the ride a little, press the tops of both buttons. When you need the tabs up, press both bottom buttons.

Forget about what the tabs are doing. It will just confuse you.

Also remember that tabs don't work instantly. They do, but it takes the boat a little bit of time to catch up. Make short 1/2 to 1 second bumps on the switches and then wait 3 or 4 seconds to see what happens with the boat before using more tab.
 
I don't have anything to add, i just wanted to tell you all what a great thread this is. I thought that I knew how to trim a boat.... I didn't. Thanks all.
 
I used to use my tabs all the time to trim, but never really wanted to use the drives because of the stress it might put on the gimbal bearings, U-Joints, etc. I know that they are meant to be used, but since I had tabs I always figured why push it.
This past spring I put a new set of props, (different material, size, and pitch) on my 87 300 Sundancer and haven't had to use the tabs at all to plane off. All I do now is push the throttles forward, and in a couple of seconds the boat planes by itself. The props were the best mechanical investment I've ever made in the boat so far.
 
mfilippa said:
why are the tab buttons opposite? What is the logic behind this? Wouldn't be more intuitive to think of the tab position to correct the attitude of the boat?

Anyways, great thread here. I learned a thing or two.
Click to expand...


because if the starboard bow is up, pushing the top port side button will bring it down...

The port tab will fix it so the port tab is what you have to use.....
 
The easiest way to relate to the Trim Tab control is to push the button in the direction you want the boat to go. For example if you want the starboard bow to go down you push the starboard top button.

BillnPat is on target, the Trim Tabs work "across" the boat and most people find it easier to just think about the boat's attitude.

Tom McGow
Bennett Marine
 
Tabman said:
The easiest way to relate to the Trim Tab control is to push the button in the direction you want the boat to go. For example if you want the starboard bow to go down you push the starboard top button.

BillnPat is on target, the Trim Tabs work "across" the boat and most people find it easier to just think about the boat's attitude.

Tom McGow
Bennett Marine
Click to expand...

Right, sorry... right side upper tab to bring down right side bow

Thanks Tom for correcting that ....:thumbsup:...
 
A lot of boaters have there trim tabs down while getting on plane, is it a slow progression of short bursts bringing the tabs up while accelerating??? or the tabs should be down fully before throttling up???? then once on plane bring tabs all the up?
of course this is if the boat is nicely trimmed....
 
billnpat said:
A lot of boaters have there trim tabs down while getting on plane, is it a slow progression of short bursts bringing the tabs up while accelerating??? or the tabs should be down fully before throttling up???? then once on plane bring tabs all the up?
of course this is if the boat is nicely trimmed....
Click to expand...

I start with the all the way down, once fully on plane, I throttle back to my cruising RPM, then do short burst on the tabs until I get the boat riding right where I want it.
 
I start with the units down all the way everytime. If I have a load or not so good sea's, I run the tabs down on take off. After plan out, tabs up about half way on the inductors and adjust later. The run the units up just a bit.

Now I will say this about trimming the unit or units. I have owned a 1972 srv 190(sea ray) 1986 Four winns 190 horizion, 1987 Four wins 211 Lib, 1987 230 conquest Power play and final this 1990 270 sundancer. Both Sea rays need little trimming on the units. Four winns need a lot or you going to drive though the water 20% slower and burn gas, ride on an anlge with out taps. Power Play (had tabs)needs more trimming than the sea rays and less than the Four winns.
If you want speed you must have the tabs up.
 
bigblockcutlass said:
I start with the units down all the way everytime. If I have a load or not so good sea's, I run the tabs down on take off. After plan out, tabs up about half way on the inductors and adjust later. The run the units up just a bit.

Now I will say this about trimming the unit or units. I have owned a 1972 srv 190(sea ray) 1986 Four winns 190 horizion, 1987 Four wins 211 Lib, 1987 230 conquest Power play and final this 1990 270 sundancer. Both Sea rays need little trimming on the units. Four winns need a lot or you going to drive though the water 20% slower and burn gas, ride on an anlge with out taps. Power Play (had tabs)needs more trimming than the sea rays and less than the Four winns.
If you want speed you must have the tabs up.
Click to expand...

If your running tabs all the way down on take off, that means the bow is up going on plane,, and when your on plane you bring the tabs up 1/2 way?, [which on my boat pushing the bottom of both rockers[ correct me please if i'm wrong, wouldn't that bring the bow higher???:huh:
 
Yes it does. But if you start with tabs all the way down you get up on plane faster, but once there the bow is to far down and you are plowing the water. As you raise the tabs the bow comes up and you have less drag on the boat. It is a compromise, like all things on a boat, between raiseing the bow and efficient ride.
 
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