Trim Tabs

photo finish · Post by **photo finish** » Fri Jul 28, 2006 12:47 pm

Mike , That would be called the Bennett auto Tab and i have been curious about them as well.It is actually a device that is added to existing tabs.It looks pretty simple to install. Sean, I am one for back up systems.But I am not sure i would want 2 sets of tabs .Twice the stuff to mount and twice the stuff to break.I am lucky however with my engines i have no problem planing without any tab at all.

Capt. Ed · Post by **Capt. Ed** » Fri Jul 28, 2006 2:14 pm

I had installed the Bennett auto-adjust on my 36' Delta Offshore and I could never get them to work right, I turn it on the whole vessel would pitch over to Stb. like it was going to rollover. So I just never mess anymore with it. 1979 Bertram 33' FBC ALEXANDRA Port Richey, Florida [img]http://www.bertram33.com/photogallery/p ... xandra.jpg[/img] HAVE YOU SIGNED UP FOR BERTRAM PRIDE '06 yet? DO IT NOW... SPACE IS LIMITED!

Sean B · Post by **Sean B** » Fri Jul 28, 2006 8:23 pm

Mike- I have to change the cylinders to get the type with position indicators. Besides, they're alomst 20 years old now and starting to fail, seems to be due. The auto adjust system is something I would not do- trusting the boat running angle to a microchip. Besides, how would the system know to run up the tabs in a following sea, or when approaching a hairy inlet? Also, as discussed my load and bottom condition determines if/how much tab I need to plane, an auto system can't predict that either. Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com [img]http://www.bertram33.com/photogallery/p ... d_Time.jpg[/img]

photo finish · Post by **photo finish** » Sat Jul 29, 2006 1:16 am

The auto tab is not something that would replace the tabs it would be an additional tool that would be used on long runs especially in conditions where the attitude of the boat changes rapidly.I have had a couple times where i have literally had to steer the boat with the tabs . I think when i have a low fuel tank and everyone is on the fly bridge the boat gets top heavy. so if there is wind and current the deep v digs in and makes keeping the boat from steering itself hard sometimes.Those are the times that having the auto tab would be nice if it works as they say it does.It is basically a gyro that remains flat and when the boat lists ,it self adjusts It is not something that i would use all the time but there are times where it would be nice to have .....if it works. .

Sean B · Post by **Sean B** » Tue Aug 29, 2006 8:55 am

Well I got the bottom job done last week: [img]http://www.bertram33.com/images/uploads/IT Bottom Small 2.JPG[/img] [img]http://www.bertram33.com/images/uploads/IT Bottom Small 1.JPG[/img] If you're wondering about the white running gear, it's because I followed Gene's advice on the painting schedule (two coats of Interlux 2000E epoxy, followed by three coats of Trilux). And I liked the white running gear idea, so I stole that too. I also had them do all the thru-hulls with the white Trilix. The guys at the boatyard said they'd never seen or heard of that before, but liked the idea a lot. Now I will always be able to pick out my boat underwater, and the gear and thru-hulls will be easier to see in murky water. Basically everything metal below the waterline is white epoxy now, except for props. I (finally) got my balanced 20x23 (added an inch of pitch) props installed with the grey "Mussel-Buster" coating on them. Hopefully the combination will be the end of my fouling issues for a while. Because I have had a jam nut keep coming loose on me despite where/how I installed the cotter pin, this time I had them install the props ala Seaboard Marine / Tony Athens' method using SS wire through a hole in the (larger) jam nut, aircraft-style. Another innovation the boatyard guys never heard of before. I also got Bennett conversions for the tab cylinders, so I could keep using the existing Insta-Leveler pump system which is fine, and got the upgraded for tab position indicators. Bennett's position indicator looks like this: [img]http://www.bennetttrimtabs.com/TPI1.jpg[/img] The Bennett cylinders have no external hoses to get fouled up like I had before. So anyway, now I've got a nice comfortable 2400 RPM 21-22 knot cruise, and am very happy with that. I can plane the boat out at 18 knots again with the tabs too, doesn't plow around like a pig at that speed anymore. WOT is 2900 RPM at 26-27 knots. So once again it's all smiles at the helm on our boat. Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com [img]http://www.bertram33.com/photogallery/p ... d_Time.jpg[/img]

Post by **dougl33** » Tue Aug 29, 2006 10:09 am

Sean, Glad to hear things worked out. I'm guessing you won't be changing tabs any time soon? Maybe a dumb question, but what did you do to fill the holes where the old piston hydraulic lines had been? How do the new pistons work? It looks like you added some angle iron to the trailing edge of the tabs. Why? Regards, Doug L. 1986 33 Bertram FBC Queen Elizabeth Marblehead, MA [img]http://www.bertram33.com/photogallery/p ... sabeth.jpg[/img]

Capt. Ed · Post by **Capt. Ed** » Tue Aug 29, 2006 12:33 pm

quote:I had them install the props ala Seaboard Marine / Tony Athens' method using SS wire through a hole in the (larger) jam nut, aircraft-style. Another innovation the boatyard guys never heard of before. I like that idea a lot, could you post a close-up photo of this? My guys are a bit slow in the reading department, but they sure like to look at pictures based on the number of magazines they have that are full of pictures. [:D] 1979 Bertram 33' FBC ALEXANDRA Port Richey, Florida [img]http://www.bertram33.com/photogallery/p ... xandra.jpg[/img] HAVE YOU SIGNED UP FOR BERTRAM PRIDE '06 yet? DO IT NOW... SPACE IS LIMITED!

Sean B · Post by **Sean B** » Tue Aug 29, 2006 12:50 pm

The old tab holes were sanded faired and filled with epoxy. The Bennett pistons are a bit bigger in diameter, so it takes more fluid to move them, and as a result they are a little slower to travel their working length than the stock pistons. About 6 seconds from full-up to full-down. Still fine but a bit slower, but the whole system is less stressed with more fluid volume behind the pistons. The angle iron was a part of the conversion kit from Bennett for my particular boat/tab setup, it is just how Bennett sets them up. No I'm not adding bigger or more tabs anytime soon. I was just down at the docks checking my tie-up for our minor TS windstorm event tomorrow, and I had a good look and talk with the owner of a B35 in our Marina that I haven't managed to run across before. The stock tabs on his boat are three times the width and twice as long as mine are, and our boats aren't all that different. Makes me continue to think about bigger tabs. Even at 21 knots and no tab, I put them down and I gain a knot. Have to wonder what bigger ones would do. The B35 guy got repowered with 355 Cummings 6B's, so he's got quite a bit more power and says he doesn't generally mess with the tabs while cruising around at 25 knots. I suppose that would be the case with our hulls too, but I don't have the engines to do it (yet). Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com [img]http://www.bertram33.com/photogallery/p ... d_Time.jpg[/img]

photo finish · Post by **photo finish** » Tue Aug 29, 2006 2:42 pm

The bottom looks great Sean.My boat is due soon. May i ask what you pay over there for the paint job. I do not see shaft zincs? You are really zinced up.I only have shaft zincs. Also curious about mussell buster

Sean B · Post by **Sean B** » Tue Aug 29, 2006 4:30 pm

I've been without shaft zincs for at least 8 months now with no ill effects. It was an experiment that was started by my dive service lying about checking the zincs, could be a lot longer. When they were on, I noticed they did not corrode much at all, and I've got a big ding in one of my last set of props that I suspect was from my own zinc falling away. No halos in the paint anywhere so seemingly I have no stray current issues. So I decided to leave them off for now, keep an eye on things and see if they remain okay that way. The european custom is no shaft zincs, and their argument against them sounds as good as the argument for them. I think if you have current leaking from your boat engine wiring you will need/use them. The wiring of the electrical ground in your marina can also effect current leaks. I don't seem to have any of those issues. The big square "diver zinc" is an add I did, and it is tied into the entire bonding system which I also redid last year. It degrades slowly, was about 30% gone after 18 months, so I replaced it. The rudder and tab zincs also go so I keep them up. The swim platform supports are not tied into the bonding system at all because I can't get to the bolts without more elbows in my arms, and those zincs also degrade. I added those 18 months ago (the boat never had them before me) and they were also maybe 30% eaten. As for bottom job costs, about $400 for haul/scrape/pressure wash. Then $15 a foot for sanding and one coat of the hard epoxy Petit Slime Resistant. I didn't want two coats, trying to minimize paint build-up and the existing paint was in fair shape anyway. So about $900 for the basic one-coat hard-paint bottom job. They stuck me for about $800 more for the special painting I requested on the running gear (from Gene's advice), which surprised me at first but as I saw was a lot of work, and maybe was a fair price. I also got the hullsides compounded and waxed below the rubrail because I hate trying to do that in a dinghy. $400 for that, and they look new. Basically everything I can't do in the water I have to get done by others, because there are no do-it-yourself yards within an hour drive from me. Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com [img]http://www.bertram33.com/photogallery/p ... d_Time.jpg[/img]

Capt. Ed · Post by **Capt. Ed** » Tue Aug 29, 2006 4:31 pm

My driver tells me that too many zincs and you become a battery, defeating the purpose of having zincs. A Hat across from he was over Zinced who was having problems, until they reduced his zincs (he felt that if two were good on his shaft... that 5 would be GREAT! 1979 Bertram 33' FBC ALEXANDRA Port Richey, Florida [img]http://www.bertram33.com/photogallery/p ... xandra.jpg[/img] HAVE YOU SIGNED UP FOR BERTRAM PRIDE '06 yet? DO IT NOW... SPACE IS LIMITED!

Sean B · Post by **Sean B** » Tue Aug 29, 2006 4:41 pm

I don't think I'm over-zinked, not sure how one would know. How did your Hattercrap buddy figure it out? I think that the three swim platform zincs are independent of everything else (and each other) because they are not connected to anything electrically. After that, I've got two rudder, two trim tab, and the transom dive zinc, which is all normal stuff. Before re-doing the bonding system my boat ate rudder zincs for breakfast, like 75% gone every month. They last over a year now after rewiring the bonding, so I think I'm in good shape. The other zincs last longer. Not sure why the rudders like to go faster- the lowest ones maybe? Now if only I could figure out how to make the CAT heat exchanger zincs last longer, those are SO much fun to change. Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com [img]http://www.bertram33.com/photogallery/p ... d_Time.jpg[/img]

Sean B · Post by **Sean B** » Tue Aug 29, 2006 4:47 pm

quote:Originally posted by photo finish Also curious about mussell buster Forgot to answer that, but I really can't for a few weeks until things have a chance to grow. Tonight I met a guy in our Marina with a B35, and he says he's had the mussel buster for two years and never had to scrape his props again. Can't wait to have those problems (nothing underwater to scrape) Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com [img]http://www.bertram33.com/photogallery/p ... d_Time.jpg[/img]

Capt. Ed · Post by **Capt. Ed** » Tue Aug 29, 2006 5:07 pm

I don't think your are over zinced either, as I have the two shafts, two rudder and two trim tabs. I will ask my diver when he is here about the Hat. 1979 Bertram 33' FBC ALEXANDRA Port Richey, Florida [img]http://www.bertram33.com/photogallery/p ... xandra.jpg[/img] HAVE YOU SIGNED UP FOR BERTRAM PRIDE '06 yet? DO IT NOW... SPACE IS LIMITED!

photo finish · Post by **photo finish** » Tue Aug 29, 2006 5:25 pm

Ed, i have heard you can over zinc as well .Sean, I am sure you are ok. I only have shaft zincs and have been told by the yards that i dont need any more because my metal looks fine. Why does a boat need zincs on the rudders and the tabs ? The zincs after all are to prevent metal corrosion , Right? so if your rudders and tabs metal shows no signs of deteriation than there should be no reason to have zinc on them right? If your zincs are failing rapidly ,that really should not mean you need to double up your zincs because in theory than you are just eating up double the zincs. but instead you need to find the source of the problem usually stray current in the water. in seans case the bonding system failed(i did not know that the bonding system had such an affect on the zincs).Water quality also has an affect as i have found out. my boat was burning the shafts zincs every 2 months at home this summer in the keys i went 4 months.One last thought on so many zincs in many spots is that in theory the zinc itself should attract the stray current and it should not matter where on the boat it is ...right?