Upsizing trim tabs - advice?

My 1989 SeaRay 250DA with a Mercruiser 7.4 / BravoI I/O has the original Bennett 12x12 trim tabs. Everything 'works' fine - I can get on plane, trim the boat level, and most of the time keep the bow at a decent angle and stop porpoising, but I've noticed that even when I'm pretty aggressive at moving heavy stuff to the bow (coolers, etc) my starboard tab is almost always fully extended, and the port one is pretty close. At times to keep the bow down, I have to use the power trim and leave the sweet spot - I can hear the engine bogging a touch. I'm getting ready to install the ATC system, and I'm thinking that I could also benefit from some larger surfaces.

LOA of the boat is 26' 9". From what I've read, 24x9 should be adequate, does that sound reasonable? Should I be looking at 24x12 or 30x9 instead? I'm assuming that going from 12x12 to 24x9 I can use the same pump and actuators, but that I'll have to move the actuators? Does a surface that large need dual actuators, or am I OK with a single?

Here's a shot of the transom of the boat (excuse the worn bottom paint). It's an 8.5' beam, so I'm not sure the 30" planes will fit.

Thanks in advance for any advice or thoughts!

You sure the OEM is 12x12? They look like 12x9? 12x12 should be more than adequate for your size boat. I just upgraded from 12x9 to 12x12 with drop fins and it made a HUGE difference... Now I can punch through the waves and get on plane much faster, stay on plane 300 rpm slower... the drop fins allow me less wander at no wake speeds too...

Note the extension to get the 12" from a standard 9" trim plate....

I'm pretty sure they're 12x12 and have a slightly different mount style than yours. Its even possible that the surfaces aren't Bennett, but the pump/controls/actuators are. I'm definitely undersized for this boat - she's pretty stern heavy as lots of the older Sundancers tended to be. I posted over at THT and Tabman suggested 24x12's, so I'll be planning on installing those soon.

Oh, and I've heard good things about the drop fin style tabs, but I'm a bit concerned they might be an issue with my dry storage. They use forklifts to move the boats around, and trim tabs are always a point of possible issue. I'd be worried that even fully retracted, that the drop fins would possibly be in the way for the forklift.

Thanks for the reply!

Be really interested in how the new tabs work on your boat I've been looking at some larger than the 12x12 bennets I have it can get pretty rough around here as you know if you can't stay on plane it's a slow ride back. I'm in dry storage also and the fins are a definite no they won't even pick up a boat with them on can't blame them for not wanting to damage a boat.

Exactly on the drop fins - they're pretty good about it at the Edmonds dry store and will try to work around them, but the risk is too high. I'll let you know how they work out - I'm hoping I can get them installed sometime next week (out of town for the long weekend) and get a chance to try them before the nice weather goes away!

I'm really hoping they help with planing at slower speeds, keeping the bow attitude better without using power-trim and compromising the prop angle (and efficiency), and just overall better trim responsiveness.

Contact Bennett. "the Tabman" Best customer support of any company I have dealt with. They will tell you what is best for your application.

Happy Hour IV said:

Contact Bennett. "the Tabman" Best customer support of any company I have dealt with. They will tell you what is best for your application.

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I cross-posted to THT forum knowing that Tabman frequents that board and he got back to me with his advice. I agree, Bennett has great support - heck I've seen Tabman respond and help folks with Lenco tabs. Not try to switch them to Bennett tabs, but help them troubleshoot their Lenco tabs...amazing!

Check with Tabman. They have a device that will automatically retract your tabs whenever you shut off you engines.

I have nearly the identical boat except a few years newer and the identical 12 x 12 tabs. I don't have the boating conditions that you have and I still consider the tabs undersized. The installation on the 95 is bastardized with a Bennett hydraulic pump, probably Bennett tabs, a Sea Ray harness and an unknown tab switch. I'll be interested to hear what you do and how you like it.

One piece of advice..... invest in the auto tab retractor device. It is inexpensive and east to install. I am also in dry storage and it makes for one less thing to be concerned about.

Edit: I just read your THT thread and see that you have plans for the ATC which would preclude the need for the tab retractor.

boykster said:

I cross-posted to THT forum knowing that Tabman frequents that board and he got back to me with his advice. I agree, Bennett has great support - heck I've seen Tabman respond and help folks with Lenco tabs. Not try to switch them to Bennett tabs, but help them troubleshoot their Lenco tabs...amazing!

Click to expand...

The auto tab retraction device on my boat is me.. I have a push button installed on the dash that when depressed starts the retraction process. All I did was cut into the power up (blue wire) on the trim pump and they come all the way up. I love it in that After coming up on plane all I do is hit the button and after they are up, I'm usually done checking for all engine gauges in the right band and then I concentrate on leveling out the tabs then go to auto trim...

You can see the button to the right of the auto trim pad on top of the dash...

Does the ATC include auto retract? I've read so many manuals lately I'm confused and/or forgotten. Or does coming off plane with the ATC on just put the tabs in the retracted position since it's trying to get the bow up (to optimal angle)? Either way, its part of my ritual to make sure the tabs are retracted and the stern drive centered. Our haul out requires a pretty tight quarters J-turn to get into position for the lift, so I'm used to having to get things squared away.

I'm actually thinking that since I'll have everything apart to wire in the ATC and move the actuators that I might add the EIC5000 control as well so I have the full deal - auto control, indicators, and tab retractors....hmmmm.....

You are correct, it is the EIC that has the tab retractor functionality, not the ATC.

boykster said:

Does the ATC include auto retract? I've read so many manuals lately I'm confused and/or forgotten. Or does coming off plane with the ATC on just put the tabs in the retracted position since it's trying to get the bow up (to optimal angle)? Either way, its part of my ritual to make sure the tabs are retracted and the stern drive centered. Our haul out requires a pretty tight quarters J-turn to get into position for the lift, so I'm used to having to get things squared away.

I'm actually thinking that since I'll have everything apart to wire in the ATC and move the actuators that I might add the EIC5000 control as well so I have the full deal - auto control, indicators, and tab retractors....hmmmm.....

Click to expand...

Well, I talked myself into it - found a vendor with a 24x12 kit that included the EIC5000 control (with new actuators with sensors, pump, and all the install accessories) for less than $100 more than just buying the planes and the EIC5000 seperately, and ~$300 more than just the planes. Figure for less than $100 the new parts were worth it - my pump and actuators are 22 years old - and this way I don't have to tear apart the actuators to install the sensors.

Hopefully sometime next week I'll be installing my entirely new trim tab system with bigger planes, EIC control, and auto tab control system. Woot! Just in time to think about ending the season....

Haven't had a chance to get to the boat yet - new trim kit arrived tuesday and I had the day off of work, but I had a bunch of other projects around the house to get done and couldn't get to the marina. I figure doing the full system swap will take 3-4 hours minimum, so I didn't want to rush it. I'll need to patch the holes from the old actuators too. Getting time in the washdown/maintenance cradles on busy sunny weekends is nearly impossible, so I'm thinking I'll take the day off tuesday (or most of it) and do the work.

My plan is

1) remove the old system (pump, actuators, planes, and control pad)
2) rough patch the holes in the transom for the old actuators
3) install the new trim system with EIC control and confirm that the system operates under manual control
4) install the ATC3000 system and re-confirm that the manual controls work
5) finish the repair job on the transom where the old actuators mounted

I don't know if I'll be able to splash and calibrate/setup the ATC control that day, but if I do I will! We'll definitely be out that weekend if the weather holds, so hopefully I'll have something to report after then.

I also realized this thread should have been in the Bennett Trim forum - if a mod wants to move it, that's fine :grin:

I am very interested in hearing your impression of the change. Also, can you share where you found the deal on the tab kit?

Are there rules against links to vendors on this forum? I never know - if these links are not allowed I can remove them.

I got the trim tab kit - full kit including the EIC5000 controller from iMarineUSA - http://www.imarineusa.com/

I don't remember where I ordered the ATC kit from, but iMarineUSA has a decent price on that too...

Took the day off of work to spend at the marina installing my new trim tab system.

I measured the old tabs - they have a chord of 12" (depth) and are 10" span. I'm replacing them with 12" chord and 24" span tabs.

Here's the old stern shot



and here's the old starboard tab for reference



I started by removing all of the exterior parts - actuators and planes and by patching the holes for the old actuator mounts with Marinetex. I overdrilled the old holes, cleaned them up (they had tons of silicon in them) and filled them in with the epoxy and covered it up with saran wrap so I could move on to the new tab install. I was pleased to see that the larger tabs could re-use the existing holes for the tab backing plate and hinge, so that saved me from having to patch an additional 8 holes (4 per side). All holes were pre-drilled, filled with 5200, and then all screws dipped in 5200 prior to driving them in. For the actuator mounts, I filled the holes for the hydraulics and wiring with 5200 as well, and then beaded around the base of the actuator mounting plate with 5200 to seal it.

Here's the port side tab mounted and you can see my marinetex patch above it



and here it is with the actuator attached



same shot on starboard side - had just enough clearance for the depth transducer. I'll have to see if it impacts performance or not - I get spotty performance on plane as it was. I may switch to a through-hull



and for reference, the whole stern after



Now that the exterior work is done, time to move inside. I pulled the old pump and replaced it with the new one. I was able to re-use the old hydraulic tubing. The tubes were very mismatched in length, but to save time today, I didn't fix that. I may remedy it later by lengthening the starboard tubing, but we'll see. The new pump dropped right into the old bracket. I hooked everything up to my existing controls to bleed the system and make sure that everything was working fine.

I then mounted the EIC relay and connected it to the keypad to make sure that part of the system worked.

I mounted the relay close by right next to my house battery bank and conveniently located near the existing wiring. The old wiring for the manual control will be used to connect to the ATC control box.



The hardest part of the install was running the EIC control wire from the stern up to the dash, but it wasn't that big of a deal. Once I had that wiring up, I pulled the old manual control, crimped on a wiring harness to connect it to the ATC3000 brain and installed the controls. I ended up putting the ATC control unit behind the gauge panel on a flat area under the compass. Power connections were easy since I had access to +12V and switched +12V.

Here's a shot of the dash before, and the eurostyle rocker

Dash


Rocker


Dash After


EIC5000


ATC3000


Unfortunately I didn't get a chance to take her out and test out the tabs...by the time I had everything all back together, the dry storage staff was closing up shop. :smt089

Everything seems to be working though - I calibrated the EIC unit, and the auto-power off works great. I also powered on the ATC unit and fake calibrated it in the cradle so that I could test the manual override - it works fine. I'll hopefully get a wet test this weekend!

I have to say it was a breeze to install overall - the wiring diagrams were helpful, the hardware kits had everything you needed, and the quality of the parts were top notch.

Oh, and I'm glad I decided to go whole hog and replace the actuators and pump - it turns out my pump has been leaking a bit over the past season or 2. I didn't notice it but when I went to pull it out there was a small puddle of ATF in the corner underneath it.

I'll update the thread when I get a chance to experience the new tabs and the ATC!

Great write up and pictures, I'm considering doing mine. At no wake speeds I constantly have to rock the wheel back and forth. I'm thinking of changing out my tabs to the bat-wing style, I've heard they help reduce the wandering of a single engine setup. Also the ATC is a no-brainer to me, I definitely want to hear how yours are working for you.

Excellent write up, thank you. I am very interested in your impressions of the new gear.

Finally got a chance to test the new gear out on the water - one word...WOW!

I can't believe how much of an impact the larger tabs have on the handling and overall 'feel' of the boat. The water today was pretty typical for the Puget Sound - not too bad but a persistent chop that changes direction depending on where you are. I did my usual routine to get up on plane - outdrive trimmed all the way down, power up to close to WOT, and then use both tabs to 'bow down'. I was so used to my old small tabs that I over tabbed and didn't think I was on plane because I didn't get the usual bow rise. Once I got used to the larger surfaces, it was a breeze getting on plane, and I was able to hold plane at a much slower speed than usual - and still see because I could keep the bow down. The biggest difference is that I have much more control over the running attitude of the boat - using about 1/2 tab extension I can keep the bow further down than I could with the old tabs fully extended, and I still have plenty of additional throw to adjust things as I need to. I used to have to use outdrive trim to keep the bow down this far, but now I can trim it up, and use the tabs to keep the boat more level. this was all with manual control - I wanted to see how the boat would work/respond doing things manually before I tried out the ATC. My wife immediately commented on how the boat seemed 'smoother' and we weren't getting beat up by the chop like we usually do....Overall, I'm VERY impressed with the larger tabs and would recommend them to anyone who is frustrated with their existing tabs and not having enough control. Its almost like driving a different boat.

The ATC wasn't as good of an experience, but I think I need to find a different mounting location for the control box / sensor. It all clearly was working - I got the boat at a good running attitude and pressed the calibrate buttons, the blue LED flashed, and then I turned the system on. I could over-ride it with the manual controls, turn it on/off, and see it making adjustments to the tabs, but the only problem was that it kept making the boat list to port all the time. I tried re-calibrating it several times at different speeds, different running attitudes, etc but it kept adjusting things wrong. I'm going to try an alternative location and see if that makes a difference.

The EIC control is great I have to say - good tactile feel, really cool having the electronic indicators of where the tabs are, and the auto-retract feature worked like a charm. One less thing to worry about when I come into the lift.

Overally - very impressed and happy with the new gear. Once I get the kinks worked out with the ATC install location, I'll be super happy!