posted 07-08-2011 10:26 AM ET (US)        

With input from Tom McGow and Tom Clark, I picked 14x12 trim tabs as ones that would be the biggest that would fit. Bennett has a huge number of sizes in stock that are not listed. I installed them as close to the centerline as I could, including trimming the vertical part of the tab mounting plate to match the angle of the transom ridge. After installation, it appears I could have maybe even fit on 16x12 tabs. I did not reinforce the transom any and don't see any need to do so based on the 0.5" fiberglass I drilled through. I did use 3M4200 to seal the trim planes and 3M5200 at the actuator top.

I have a hybrid actuator, with a 3.5" stroke versus the normal 2.5" stroke. That lets me retract it farther than normal while still getting full deployment. It was not intended to end up like that, but it worked out well - even fully retracted I can tell they are there coming up onto plane with slightly less bow rise. With them fully down the boat has very minimal bow rise getting on plane. I can run in a planing mode at around 14-15 mph (tabs not all the way down), as well as reasonably run even slower with a bow somewhat high mode. Bennett can mix and match parts on the actuators to get different overall lengths and different total stroke lengths.

I had trouble with the hydraulic connections at first, but that was my error due to not tightening the nipple (that goes through the transom) sufficiently into the actuator top. So I had to dissemble it once then put it back together - no leaks then and not long to re-do - maybe an hour.

The tabs are setup so that the edge on the transom is totally flush with the bottom - not raised at all. Bennett has a smooth hinge in that area that is intended to be mounted flush - mounting flush also results in the most lift with the least drag, as you get more tab in contact with the water surface with less angle.

I do get some spray onto the motors at some trim conditions - mainly with the tabs far down at higher speeds. The only time I'd envision putting them down that far is for watersports.

Assembly was not hard, but at least for me it was time consuming figuring out just how I wanted to mount it. I also had to trim the bottom edge of the quarter boxes a little for where the nipple comes through. The system is very simple and appears robust.

I also bought the EIC5000 control/indicator, but have not hooked up the indicator wires yet, so I can't comment on how that yet. I'll likely get them connected and in use this weekend.

I've not really had much difficulty with side-to-side trim - my main interest was lower planing speed and better operational in the transitional speed, and that has been achieved.

After I have time to study the water flow and usage more, I may end up adding the bolt-on 3" drop down fins on one or both sides. Tom McGow estimated that the fins would result in the 14" wide plane behaving more like an 18" wide plane - the larger effective plane would allow more lift with less drag (due to less deflection being needed). Tom Clark has reported that plane with integral fins did not work well on his Revenge 25 because the fin was not parallel with the water flow, resulting in more spray. With the bolt-on fins there can be modest adjustment of angle, so they may work.

posted 08-02-2011 09:17 AM ET (US)            

Without tabs, my boat would plane out at about 3000 rpm, and plow from 2000-2800 with a very high bow.

With tabs fully down, the bow never really rises significantly - rather, the boat sort of "planes out" starting around 2300 rpm, which is about the speed we pulled kids on skis. For kneeboarding and wakeboarding we pulled at about 2500-2600 rpm, adult skiing about 2800 rpm, and slalom skiing about 3200 rpm. I don't have a speedometer that I leave on the boat but instead just a handheld GPS, so I don't have much speed data - we've always used RPM data for pulling speeds. Actual speed would vary some for a given RPM, as we had anywhere from 1 person onboard to 11 people, though normally pulling with 4-5 onboard plus 1-2 skiers.

It was interesting to experiment with the tabs to see how they would impact the wake shape. A couple of examples.
1. With the tabs all the way down at 2800 rpm, a roostertail would shoot out of the water about 30 ft behind the boat, where the compressed water from the tabs would rise back up. Raising the tabs partway eliminated the tail. The tail might shoot 2-3 ft above the water surface.
2. At 2600 rpm, you could adjust the size of the wake. The more deflected the tab, the flatter the wake, and the less deflected the tab, the larger the wake.

As you might expect behind a 5000 lb boat, the wake is always too large for good slalom skiing - you cannot really lay the ski down hard on the edge through the wake as the tail will kick out and you'll fall. However, for everything else, the wake is fine, and for kneeboarding and wakeboarding specifically, the wake is great.

posted 04-10-2012 10:19 AM ET (US)            

I've only used them one season so far, but I use them a lot, often heavily deflected, and have seen no indication of any problem of mounting directly into the fiberglass.