Trim tab issue (Tabman?)

[Fistful]

I have just recently bought a 2000 model year 221 Sportcraft. This particular model had factory installed Trim Master trim tabs. When I first bought it the owner had mentioned that he did not use the trim tabs because it “practically threw him out of the boat.” Hence he did not use or pay attention to them for the duration of ownership.

After troubleshooting it a little, I found that there appeared to be a previous leak from the reservoir/motor that stained the inside transom wall where mounted. I filled it with ATF as it was near empty. While on the trailer I proceeded to actuate the port and starboard tabs to bleed the system as I had learned by reading many previous posts here (thanks Tabman). Everything appeared to function as normal, although the starboard tab reacted slower than the port (reservoir is on the port side). I attributed this to the greater distance of that line. After a few days of sitting there I noticed that it was again leaking AFT from the reservoir? However, inspecting it a few days later, it did not appear to have leaked any more, perhaps I over-filled it? I doubt it as I was very cautious to not top it completely off.

Now fast forward to my first on the water experience this past weekend. While traveling up on plane (28 mph) into an 18” chop I thought I would make a slight adjustment to drop the bow and compensate for a small port lean. Actuating the appropriate tab (starboard bow down) the boat aggressively veered starboard which required some major steering correction. I then brought the tab back up and tried actuating the port tab with very similar results (aggresive port turn). In both cases, there was a very delayed reaction to my adjustment, then wham. I really did not play with it too much more than a couple tries as it was a bit concerning how much it was throwing me around.

As some background, I grew up using Bennett trim tabs on my father’s boat and consider myself very comfortable operating and understanding the use of them. Even when I purposely over adjusted on his boat (1999 25’ Proline), it never created such an aggressive correction. Furthermore, I really do not like the two dash knobs on the Trim Master unit, there does not seem to be any feedback as to how far I just actuated a particular tab. If I recall, Bennett seemed to have some sort of a click when you depressed the toggle and the adjustment was very subtle yet noticeable.

I guess my long winded questions are:

• Is there something faulty with my Trim Master unit or is this just the difference between brands? Recall, the original owner described this from the outset.
• Could I have some sort of wiring/hydraulic issue based upon the details provided?
• Lastly, how difficult would it be to retro-fit this with a Bennett motor/reservoir/dash actuator? Is that possible?

Thanks for reading and your thoughts.

Tom

 

[Tabman]

Re: Trim tab issue (Tabman?)

Tom,

My first impression is that there is likely nothing wrong with the the way the Trim Masters are working. I think you experienced what is known as "bow steering". I suspect that you may have had the bow trimmed down with the power trim, and or the boat is naturally assumes a bow down attitude at the speed you were going.

When you actuated one of the Trim Tabs, even tough is was port or starboard, it also added a bit of bow down (this will be particularly true if the Tabs are not mounted out towards the chines) and this dropped the sharp forefoot deeper in the water causing the boat to shear off to that side.

The first thing I would suggest is to trim the drive out a little bit and carefully try using the Trim Tabs again. I am pretty sure you will have much better results. All boats are different and yours will react differently than your dad's.

Ok, there could be an issue is the Trim Tabs were mounted incorrectly on the transom. To be sure is there any way you could post photos of them up and down? That way we can rule that possibility out.

You can quite easily swap the controls to Bennett (yes the positive click is great for small adjustments) and you can exchange the pump too. But let's try playing with the power trim and make sure the Tabs are mounted correctly before spending any money.

 

[Fistful]

Re: Trim tab issue (Tabman?)

Thanks Tom. I have included a picture that happens to show the starboard trim tab. From everything I can gather it seems to start level or higher and then achieve a 2-3 inch drop when fully engaged. I will try to get some more detailed pics when I get out to my boat in a few days. I will be back on the water with it then as well...hopefully I can play around with your suggestions.

The part that did not make sense to me was regarding the motor trim being too "low". I noticed if anything the boat actually struggled on the holeshot with no tabs engaged and the motor fully trimmed down. That is with a 200 EFI 2-stroke which i would think is plenty of muscle to jump on plane. Just seems to go against the over trimming theory.

Thanks again for your insights.

 

[Outsider]

Re: Trim tab issue (Tabman?)

Tom would have a better perspective, but if that tab is supposed to be 'fully retracted', you may have a mounting problem. Extend a straight edge along the hull and out past the trailing edge of the tab, if the tab touches it anywhere ... :facepalm:

 

[Tabman]

Re: Trim tab issue (Tabman?)

Good eye Outsider!


It certainly looks to me that that Trim Tab is in the fully retracted position and is angled down from the plane of the hull bottom.

This means that it always going to be generating lift, even when retracted. And when you go to apply some Tab it will make lots of lift right away. The Tabs mounted this way will make the boat run bow down at higher speeds even when retracted.

As Outsider mentioned, place a straight edge under the hull, when fully retracted your Trim Tabs should be 5/8" above it at the trailing edge.

This allows the Trim Tabs to ride clear of the waterflow when retracted and will let the boat assume a bow up attitude when you want it to, such as at high speeds and in a following sea.

Maybe it's the camera angle, or the Tab is not fully retracted, but I would make sure they are fully up and double check to see if they angle up a bit in the full up position

 

[Fistful]

Re: Trim tab issue (Tabman?)

One thing I've noticed on the trim masters is that they do not return to the fully retracted position on their own (bad design or flawed operation?). In the picture shown they were still in the position I left them in while last on the water. When full retracted it does indeed come above level in relation to the bottom plane (sharp eye nonetheless).

I was able to get the boat back out on Thursday and mess around on the water. It went much better. I found the that the dash controls are extremely sensitive. Just a slight bump on the starboard and/or port knobs would be more than enough to make the adjustments needed. I still miss the positive click from the Bennetts. I think at some point I will like to swap out to Bennett controls, but for the time being my unit is opertional and serving it's purpose I suppose. Thanks for all your comments and feedback.