SMART TABS
- Thread starter cemiii
- Start date
"Smart Tabs", as I remember, are spring loaded trim tabs.
They are forced down by springs at rest, then at planing speeds, are forced up by the pressure of the water rushing by.
As such, there is no ability from the helm to trim laterally (or port/starboard), which is one of the main functions of trim tabs in the first place.
They probably do help get the boat on plane and effectively extend the hull length a bit for a better ride, just like any trim tab, Permatrim, or other hydrofoil.
But if they don't trim laterally, why not just get a Permatrim or other hydrofoil? You can at least trim the boat through the last two with your motor trim controls.
No doubt on certain boat applications the make for a big improvement by themselves, but I'd first go for the Permatrim or another hydrofoil, then secondly for a set of real trim tabs with real lateral controls!
Joe. :teeth :thup
They are forced down by springs at rest, then at planing speeds, are forced up by the pressure of the water rushing by.
As such, there is no ability from the helm to trim laterally (or port/starboard), which is one of the main functions of trim tabs in the first place.
They probably do help get the boat on plane and effectively extend the hull length a bit for a better ride, just like any trim tab, Permatrim, or other hydrofoil.
But if they don't trim laterally, why not just get a Permatrim or other hydrofoil? You can at least trim the boat through the last two with your motor trim controls.
No doubt on certain boat applications the make for a big improvement by themselves, but I'd first go for the Permatrim or another hydrofoil, then secondly for a set of real trim tabs with real lateral controls!
Joe. :teeth :thup
Warren-
You may be right, or maybe they've been re-designed to spring from the old school past to the new school of hot air pneumatics!
Look at this ebay listing for some old school and new school design standbys:
L@@K
I've also discovered they may offer some difficulty when backing up because they automatically hinge down:
From Wierd Walt:
OH GEEZ You have to be careful backing up, that's a major major problem with these, there is a documented case of the tabs going down and dragging the entire transom underwater. The owner sued smart tabs but didnt get a favorable ruling.
Not sure why.
Have fun, it's Saturday Night at the C-Brats Site!
Joe. :lol:
You may be right, or maybe they've been re-designed to spring from the old school past to the new school of hot air pneumatics!
Look at this ebay listing for some old school and new school design standbys:
L@@K
I've also discovered they may offer some difficulty when backing up because they automatically hinge down:
From Wierd Walt:
OH GEEZ You have to be careful backing up, that's a major major problem with these, there is a documented case of the tabs going down and dragging the entire transom underwater. The owner sued smart tabs but didnt get a favorable ruling.
Not sure why.
Have fun, it's Saturday Night at the C-Brats Site!
Joe. :lol:
Captains Cat
New member
I had "dumb" tabs on my 22. They were cast Aluminum and had the ability to move up and down but only when the boat was on the trailer and you moved some screws. I kept them set in a fixed abougt 10deg down position and they seemed to help the boat up on plane and keep the bow down a little. I had planned to replace them with Bennet or Lenco and then the TC came along! :lol:
Charlie
Charlie
My new boat has come with Smart Tabs...it's a 22' Classic with a 90 HP outboard.
As I understand it, these Smart Tabs are "gas assist" tabs...they're held down by something (the gas part, I assume) until the force of the water raises them. Now, the rubber boots on each are cracked through at the bottom, kind of the way CV boots on cars crack. Do these things even work once the boots are cracked?
Has anyone here actually used these? Are they truly a benefit, or is there also a drawback (besides the backing up problem mentioned above)? I'm trying to decide whether to remove mine or leave them on.
Thanks for any help or advice ya'll can give.
As I understand it, these Smart Tabs are "gas assist" tabs...they're held down by something (the gas part, I assume) until the force of the water raises them. Now, the rubber boots on each are cracked through at the bottom, kind of the way CV boots on cars crack. Do these things even work once the boots are cracked?
Has anyone here actually used these? Are they truly a benefit, or is there also a drawback (besides the backing up problem mentioned above)? I'm trying to decide whether to remove mine or leave them on.
Thanks for any help or advice ya'll can give.
Do yourself a big favor by removing the "smart" tabs and putting in a good set of hyraulic trim tabs (might also consider a Permatrim). The difference in ride in a chop will amaze you--and make the boat better handling.
The "smart tabs" basically are deployed by a spring/gas shock, until water pressure of the boat going thru the water on a plane pushes them back to a level attitude (the same plane as the bottom of the boat). They offer no control--no way to push the bow down when going into chop--or allow the bow to come up, as you go down waves.
They will work moderately well in very small boats--in allowing the boat to get on a plane faster--but any of the add on foils or fins which go on the lower unit cavitation plate of the motor will do the same thing. The smart tabs will not allow you to make changes in lateral trim (side to side heel or list of the boat)
You want to also be sure that there is no dry rot in the transom where the smart tabs were screwed in place--fill these holes--preferably with epoxy.
The few hundred dollars spend to good hydraulic trim tabs are probably some of the best money spent on a CD 22.
The "smart tabs" basically are deployed by a spring/gas shock, until water pressure of the boat going thru the water on a plane pushes them back to a level attitude (the same plane as the bottom of the boat). They offer no control--no way to push the bow down when going into chop--or allow the bow to come up, as you go down waves.
They will work moderately well in very small boats--in allowing the boat to get on a plane faster--but any of the add on foils or fins which go on the lower unit cavitation plate of the motor will do the same thing. The smart tabs will not allow you to make changes in lateral trim (side to side heel or list of the boat)
You want to also be sure that there is no dry rot in the transom where the smart tabs were screwed in place--fill these holes--preferably with epoxy.
The few hundred dollars spend to good hydraulic trim tabs are probably some of the best money spent on a CD 22.
A
Anonymous
Guest
I have become a fan of the Bennett individually-adjustable hydraulic trim tabs which Les installed on the J.C.Lately (CD-22).
HOWEVER, be advised that the common installations lack a panel indicator of the state of each tab which I find to be an unfortunate shortcoming of the system. Not a deal-breaker; just a shortcoming.
Paul Priest
Sequim
HOWEVER, be advised that the common installations lack a panel indicator of the state of each tab which I find to be an unfortunate shortcoming of the system. Not a deal-breaker; just a shortcoming.
Paul Priest
Sequim
thataway":31lx07az said:
Thanks.
I'm busting my budget getting the boat fixed up and into the water, so definitely won't be buying the hydro trim tabs any time soon. Do you think that having the Smart Tabs on there is worse than nothing at all? In other words, should I remove the Smart Tabs even if I don't replace them with anything?
Keep in mind that you can buy Instatrim Boat Levelers for about $330 for the complete kit. This was standard on the 25's in the 2003 era. I had to put in a new motor, because it had been submerged, but it has worked fine and we have put on several thousand miles in the last year.
I did put a indicator on one of my boats with tabs, and it was convient to set up the boat, but I didn't see any great advantage when running. I tend to trim for the conditions.--and vary the trim as needed by sea condition. I start off with the tabs full down, and then bring them back up.
I don't think that leaving the smart tabs on will hurt any thing. See how much resistance there is against the spring/shock. They may just be flopping up--and if that is the case, they are not doing any thing for you. It is difficult to know if there is any moisture in the transom, without removing screws--I personally would remove screws, check for rot, and then put in epoxy, and rebed the screws to prevent any rot in the future.
I did put a indicator on one of my boats with tabs, and it was convient to set up the boat, but I didn't see any great advantage when running. I tend to trim for the conditions.--and vary the trim as needed by sea condition. I start off with the tabs full down, and then bring them back up.
I don't think that leaving the smart tabs on will hurt any thing. See how much resistance there is against the spring/shock. They may just be flopping up--and if that is the case, they are not doing any thing for you. It is difficult to know if there is any moisture in the transom, without removing screws--I personally would remove screws, check for rot, and then put in epoxy, and rebed the screws to prevent any rot in the future.
I would think that if you hand spring them on the trailer and they still have similar significant amount of resistance they're probably better than nothing. However if they are wildly dissimilar in resistance, or just flapping in the breeze, they're mosy certainly not doing you any good.
Chris
Chris
As usual, Dr. Bob is spot on IMO.
If you just once get in a following sea of any size, you will rush home and take those rascals off. I see little advantage to them (except they are already there and cheap), and many disadvantages. And yes, I've had them -- and also the kind that Charlie (that old guy on the wrong coast) had. Save up and get some good hydraulic ones.
Dusty
If you just once get in a following sea of any size, you will rush home and take those rascals off. I see little advantage to them (except they are already there and cheap), and many disadvantages. And yes, I've had them -- and also the kind that Charlie (that old guy on the wrong coast) had. Save up and get some good hydraulic ones.
Dusty
Captains Cat
New member
Sawdust":1c0f9mzy said:
:shock: Whadda you mean old? You've had more of these :cake :cake :cake :cake than I have!
I sure regret not putting the permatrims on the Suzi engines on the TC before I put it back into the water this summer. Oh, well, I'll just have to do it next haulout, Gotta remember where the screws are now....
Charlie
Another way to look at is , if the boat runs well and is comfortable to drive with them on keep em . If not remove them .They are somewhat adjustable as to their leverage as well and If the bow is not pushed down too much they will probably be alright . Probably need to play with engine "up" trim a bit though in flat water.Dont be afraid to trim it up till it cavitates and then back it down till it bites again .thats your trim range .
Marc
Marc
OK, I thought some of you who posted responses to my questions might appreciate the outcome of my Control-Experiment pair of sea trials. Note that in addition to posting my questions, I had also called the Smart Tab factory before taking the boat out to verify that these things were the right fit and location for the boat.
Trip #1 (Maiden Voyage): Took the boat down to Whittier two weekends ago, got it in the water by afternoon, and opened it up out on the water on a fairly calm sea - small chop, modest wind, etc. Well before getting up on step, the boat would heel hard to one side, causing me to yank the opposite direction on the wheel. Even with my "correction", the boat would basically drive at a list, like a car on two wheels. The entire crew (wife, both dogs, and the 9-month-old Junior Skipper) all appeared quite alarmed. In an especially bold moment, I pushed it up onto step and the feel was terrible - and incurred the wrath of Junior Skipper's mom. :x Not Good!
I went aft to try to observe the motor position at one point, but that didn't work out well - the 1st mate lost control of the wheel and we ran in tight, albeit slow, circles for about 10 painful seconds. Not good, again. We limped back into port with some serious buyers remorse about new C-Dory purchase. I put in a call to another C-Dory owner, who told me that, regrettably, his also pulls a bit under certain conditions. Damn, not what I wanted to hear.
Next day dawned windy and cold, and I flipped the boat around in the slip and examined the hind end. One Smart Tab had a loose nut, allowing it to slide to different positions in it's bracket, while the other was fixed. Not good. I put both of them in the lowest-resistance (bow up) position, and we partnered up with another boat for the day. It was better, but not great. I found a sweet spot in the motor trim, just like Weifings predicted, but it was awfully close to the cavitation point. We could be on step with confidence, but could never get the RPMs over 4000 (WOT was supposed to be 4500-5500). Ran out to Blackstone Bay, though, and had a good day. Still not real happy about the boat.
Trip #2 (Sophomore Success):
I yanked each Smart Tab off the boat by dismantling them at the hinge (so as not to remove the mounting screws from the transom, in case I wanted them back on. That left me with two tiny hinges flapping behind, like vestigial appendages left over from a prior evolutionary phase. Took the boat down to Seward, where we wallowed out into 2 and 3 foot swells before anchoring at Caines Head. Even at 9 knots in lumpy seas, it felt much better than the prior trial.
Seas the next day were flat, so finally we got to open her up. The difference was night and day. The XerxSeas shot straight and true, with no need to cling to the wheel. I could have steered with one finger, both before and after getting on step. The motor went up to 4500 RPM with no problem, but I dared go no higher without incurring the wrath of the still-nervous crew. Perhaps my devilish laughter contributed to their unease. Whatever the case, we were 29 knots with no problem, and hints of more speed ahead.
The Verdict:
The tabs appeared to be in good shape in terms of wear and tear. On the second day, they were also adjusted evenly, and on the most bow-up setting. I believe the problem that day was that they still forced the bow down, causing the nose to dive and the boat to veer haphazardly.
So what's the story here? Were they mounted wrong, do tabs that don't manually adjust not work on a C-Dory, or is it just a mistake to have tabs on that size boat altogether?
In any case, does anyone want to buy a used set of Smart Tabs?
:wink [/b]
Trip #1 (Maiden Voyage): Took the boat down to Whittier two weekends ago, got it in the water by afternoon, and opened it up out on the water on a fairly calm sea - small chop, modest wind, etc. Well before getting up on step, the boat would heel hard to one side, causing me to yank the opposite direction on the wheel. Even with my "correction", the boat would basically drive at a list, like a car on two wheels. The entire crew (wife, both dogs, and the 9-month-old Junior Skipper) all appeared quite alarmed. In an especially bold moment, I pushed it up onto step and the feel was terrible - and incurred the wrath of Junior Skipper's mom. :x Not Good!
I went aft to try to observe the motor position at one point, but that didn't work out well - the 1st mate lost control of the wheel and we ran in tight, albeit slow, circles for about 10 painful seconds. Not good, again. We limped back into port with some serious buyers remorse about new C-Dory purchase. I put in a call to another C-Dory owner, who told me that, regrettably, his also pulls a bit under certain conditions. Damn, not what I wanted to hear.
Next day dawned windy and cold, and I flipped the boat around in the slip and examined the hind end. One Smart Tab had a loose nut, allowing it to slide to different positions in it's bracket, while the other was fixed. Not good. I put both of them in the lowest-resistance (bow up) position, and we partnered up with another boat for the day. It was better, but not great. I found a sweet spot in the motor trim, just like Weifings predicted, but it was awfully close to the cavitation point. We could be on step with confidence, but could never get the RPMs over 4000 (WOT was supposed to be 4500-5500). Ran out to Blackstone Bay, though, and had a good day. Still not real happy about the boat.
Trip #2 (Sophomore Success):
I yanked each Smart Tab off the boat by dismantling them at the hinge (so as not to remove the mounting screws from the transom, in case I wanted them back on. That left me with two tiny hinges flapping behind, like vestigial appendages left over from a prior evolutionary phase. Took the boat down to Seward, where we wallowed out into 2 and 3 foot swells before anchoring at Caines Head. Even at 9 knots in lumpy seas, it felt much better than the prior trial.
Seas the next day were flat, so finally we got to open her up. The difference was night and day. The XerxSeas shot straight and true, with no need to cling to the wheel. I could have steered with one finger, both before and after getting on step. The motor went up to 4500 RPM with no problem, but I dared go no higher without incurring the wrath of the still-nervous crew. Perhaps my devilish laughter contributed to their unease. Whatever the case, we were 29 knots with no problem, and hints of more speed ahead.
The Verdict:
The tabs appeared to be in good shape in terms of wear and tear. On the second day, they were also adjusted evenly, and on the most bow-up setting. I believe the problem that day was that they still forced the bow down, causing the nose to dive and the boat to veer haphazardly.
So what's the story here? Were they mounted wrong, do tabs that don't manually adjust not work on a C-Dory, or is it just a mistake to have tabs on that size boat altogether?
In any case, does anyone want to buy a used set of Smart Tabs?
:wink [/b]
syddyfinch-
Thanks for the report!
We've said it before, and I'll say it again:
Smart Tabs simply don't work, period.
They're designed to "automatically adjust" to trim the boat with their pre-loaded downward pressure, but have no means of control for different sea conditions, and no lateral or side to side (athwartships) adjustability.
Synopsis: Bad idea, bad engineering, poor product, amazing that they're still around fooling people! (I think the lesser price keeps them on the market, as folks seek a cheaper alternative to something that is known to work, like Bennett Tabs.)
I believe this has been stated in the threads in the archives before, several times, but, as usual,it's often hard to find these threads and most folks won't take the time to simply look them up, wanting a personal explanation instead.
Thanks for the report, it should put the nail in the coffin on this subject, but within a year or so it's come up again as long as no one has the skill to organize all this wealth of information on this site or design a Search Engine that is easy to use.
I've been here on this site 5 years and on other C-Dory sites years before, and half the threads have been discussed before, usually several if not many times.
It gets harder and harder to maintain one's enthusiasm for this site as time goes on.
I sometimes feel like a librarian who's reached retirement age.
The last few paragraphs are not directed at you, nor should they be taken as negative towards the site in general.
Maybe I've just run my course after some 4400 or so posts and need to step aside for awhile.
Joe. :teeth :thup
Thanks for the report!
We've said it before, and I'll say it again:
Smart Tabs simply don't work, period.
They're designed to "automatically adjust" to trim the boat with their pre-loaded downward pressure, but have no means of control for different sea conditions, and no lateral or side to side (athwartships) adjustability.
Synopsis: Bad idea, bad engineering, poor product, amazing that they're still around fooling people! (I think the lesser price keeps them on the market, as folks seek a cheaper alternative to something that is known to work, like Bennett Tabs.)
I believe this has been stated in the threads in the archives before, several times, but, as usual,it's often hard to find these threads and most folks won't take the time to simply look them up, wanting a personal explanation instead.
Thanks for the report, it should put the nail in the coffin on this subject, but within a year or so it's come up again as long as no one has the skill to organize all this wealth of information on this site or design a Search Engine that is easy to use.
I've been here on this site 5 years and on other C-Dory sites years before, and half the threads have been discussed before, usually several if not many times.
It gets harder and harder to maintain one's enthusiasm for this site as time goes on.
I sometimes feel like a librarian who's reached retirement age.
The last few paragraphs are not directed at you, nor should they be taken as negative towards the site in general.
Maybe I've just run my course after some 4400 or so posts and need to step aside for awhile.
Joe. :teeth :thup
Siddyfynch,
I had a set of similar tabs on a 30 footer and they were a big mess. No way to adjust laterally for wind tilt, or weight distribution.
Also, they drag heavily when you're trying to run at an economical slow hull speed.
I think the Permatrim is a wonderful fore/aft control device which smooths out your ride as though your boat were 3 foot longer. You'd still need adjustable tabs for the lateral control, BUT the Permatrim gives you wonderful extra steering control. Even drifting, the Permatrim has a bit of 'rudder' feel to it allowing you to turn with the engine in neutral.
The C-Brats collectively have probably hundreds of years experience in tab use/design, so I'd heed their advice closely and just pay out what the proper equipment costs. Compromise tabs give you a compromise result and that can be dangerous in addition to being uncomfortable.
Good luck and have fun!
John
I had a set of similar tabs on a 30 footer and they were a big mess. No way to adjust laterally for wind tilt, or weight distribution.
Also, they drag heavily when you're trying to run at an economical slow hull speed.
I think the Permatrim is a wonderful fore/aft control device which smooths out your ride as though your boat were 3 foot longer. You'd still need adjustable tabs for the lateral control, BUT the Permatrim gives you wonderful extra steering control. Even drifting, the Permatrim has a bit of 'rudder' feel to it allowing you to turn with the engine in neutral.
The C-Brats collectively have probably hundreds of years experience in tab use/design, so I'd heed their advice closely and just pay out what the proper equipment costs. Compromise tabs give you a compromise result and that can be dangerous in addition to being uncomfortable.
Good luck and have fun!
John