Smart Tabs, regular Bennett-type tabs or QL interceptors?

stevens

Senior Chief Petty Officer
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May 4, 2005
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Having read a number of discussion threads here at iboats.com, I am at a loss as to what would be the right choice of trim tabs for my boat. NautiJohn, Tabman, or anyone else - any advise would be appreciated!<br /><br />Here's a link to my type boat (hold the cursor over the thumbnail pic's to enlarge):<br /><br /> http://www.ibizaboats.no/baater.php?type=touring&gruppeid=491&id=galleri&navn=21touring&galleri=181 <br /><br />It's a 21 foot daycruiser, dry weight of about 2650 lbs, equipped with a 120 hp Mercruiser diesel, giving it a top speed of about 36 knots.<br /><br />The main problem is that it is under-powered and stern heavy, i.e. the stern digs in at any low speed, giving it a high planing treshold, a very high angle before planing, and the stern generally sits heavy in the water. In addition, being only 95 inches (240 cm) wide, the boat is sensitive to the sideways weight distribution.<br /><br />It needs at least 12-15 knots before planing, and cruises best at about 24 knots. However, this is a bit fast and skittish for the wife and kids, who would rather cruise comfortably along at 10-15 knots.<br /><br />By adding trim tabs, I was hoping to get a much lower planing speed, and a smoother and gentler ride in general. Also, I don't want to deal with anything complicated, and the ease of Smart Tabs or the Bennett ATC appeals to me.<br /><br />Now, after some rather lengthy research on the internet, I am still undecided. In your opinion, will the Smart Tabs do, or is my boat so large/heavy that it requires helm adjustable tabs?<br /><br />Any opinions on the QL boat trim system (using vertical interceptor planes rather than horisontal flaps, see www.qlmarine.com )? In particular, any views on whether or not these so called interceptors will give sufficient stern lift at low speeds?<br /><br />Finally, any views on the ATC or equivalent automatic systems (for example www.mente-marine.com )?<br /><br />I've also ordered a new Ballistic 21" SS propeller to replace the standard 23" pitch aluminium Black Max propeller, with the same objectives in mind.<br /><br />As you can tell, I am at a loss as to what to choose, but would very much want to find a solution that would not require switching to a larger and more stable boat.<br /><br />Any help would be appreciated!
 

bossee

Senior Chief Petty Officer
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Jul 18, 2002
Messages
727
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

Hi,<br />Not many boats plane at 12-15 knots.<br />It is most boats worst speed range since it will not plane and fuel consumption is usually horrible at those speeds.<br />Boats exists that has (almost) no plane treshold but Your boat seems not to be one of them.<br /><br />Try to contact Ibiza directly and ask what trim system they recommend on your boat. They have probably tested the boat with some make/model of trim system.<br /><br />QL Marine "QL Boat Trim System" is supposed to be very efficient. Since You are from Norway You can read the Swedish manual at Drevia website if you want.<br />Some sort of trim system will probably be good for your boat, at least it will help to get up on plane easier but it will not help that much for lower cruising speed. It will also help keep the boat level sideways. <br />The trim system will only force the front down and create drag if you try to cruise at 10-15 knots as you say you want to achive. About 18-20 knots - have you tried that? Usually that is a reasonably low (planing) speed, give low fuel consumption and usually rather low noise from the engine.
 

QC

Supreme Mariner
Joined
Mar 22, 2005
Messages
22,783
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

Some kind of adjustable tab.<br /><br />For me it is that simple. Some type of adjustable trim tab should be standard on all planing hulls. I got my last set-up from Eddie Marine if you like pretty, but the Bennett Sport tabs would be really good too. If you would rather have it be sorta automatic go with the SmartTabs, but I like to be able to adjust as I see fit. Not sure about availability in Norway . . .<br /><br />My 22 footer is very comfortable at 12 - 15 knots and planing with tabs way down. Not an efficient setting or speed, but it is very good in sloppy water.
 

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

Your boat plans at a very low speed. Most need 18 to 20 miles per hour to plane. My 21 foot Aluminum boat plans at about 20 MPH with out tabs. With tabs down will plan at about 11 and stay on plane to 9 MPH.<br /><br />Your boat will plan and lower speeds with any type of TABS. I prefer adjustable tabs and installed Bennett Tabs 24 inch wide by 12 inch deep per side back in 1981. It is the best thing I have ever done to my boat. It makes it ride like it was 4 feet longer. Most important is I can adjust the boat trim for best ride at any speed or any condition. Some days that is no trim at all and with a following sea always with no trim. Some days that is with half trim.<br /><br />About the only time I use full trim coming in to a dock I use a lot on a minus tide day. I trim the motor up all the way and use trim tabs full down then just a enough speed to get the boat high in the water.<br /><br />If you do go with adjustable tabs then I think the the dual rocker switch works better than the Joy stick control. At least for me very easy to use.
 

Jdeagro

iboats.com Partner
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1,682
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

Stevens;<br /><br />First of all let me say congratulations on your research work and understanding that better performance will be achieved with a trim tab system.<br />Second, I would normally say that you are premature in purchasing a new prop especially a lower pitch. However, since you did not indicate what RPMs your are turning at Top speed, we can not make a recommendation. I understand your power is diesel and the RPMs will be lower and less critical. The lower pitch prop is going to cost you additional fuel consumption, and at your prices (I am guessing about $1.25 per ltr.) that is about the last thing you want to do. Make the hull more efficient first, then work with the prop. You should be able to stay with the <br /><br />As for the choice between the Tab systems that you referenced, it will become an issue of personal use and preference. The size and weight of your boat fall into the most popular category of our market. The ST1290-80 would be my recommendation. We now make Trim Tabs for boats up to 8500 lbs. and 30 ft. They can be purchased through Watski or our distributor in Norway ( Telmo Controls , Rolf Hofmost Gt. 18 , N-0608 Oslo , Norway Tel: 22 67 2360).<br /><br />Apparently price is not an issue so we should stay with the function of the systems.<br /><br />Helm controlled tabs (ie: Bennett) allow the ability to control the boat attitude from bow to stern and port to starboard manually from the helm. There is no question that they are effective, and properly adjusted they will provide huge benefits. If the boat is a destination boat (not a sport boat) I would recommend Helm controlled tabs ( please understand that we do not make helm controlled trim tabs, we are the manufacturer of Smart Tabs).<br /><br />I personally have tested a number of boat in Sweden similar to yours and understand that they are susceptible to listing because of the hull design. They are narrow and usually have a deep V configuration. This would initially indicate that port to starboard control is better served by helm controlled tabs, however there is another factor, These boats tend to shift the list quickly and adjusting the tabs that quickly and continuously may be difficult. By the way my dream is to someday have the time to cruise your waterways as they are breathtaking.<br /><br />Smart Tabs by nature of the continuous reaction to water pressure will provide lateral stability similar to the suspension system of a car. They will not provide the degree of correction that helm controlled tabs can when one trim tabs is fully deployed and the other is retracted. In most cases on boats your size, this is not necessary because the Smart Tabs system is constantly active the degradation in attitude is minimized, and more severe corrections are not needed. In other words they keep the boat from getting too far out of balance.<br /><br />I would suggest that your choice should be made by how you use your boat, how conformable you feel with controlling the trim tabs, and your convenience factor. <br /><br />I have no personal experience with the vertical interceptor planes but have seen demonstration at trade shows. My initial response would be a concern for breakage if the boat runs across objects in the water.
 

JustMrWill

Master Chief Petty Officer
Joined
Aug 12, 2003
Messages
877
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

Anybody wonder if NautiJohn has a search bot running that alerts him to any trim tab question?<br /><br /> :) <br /><br />-JustMrWill
 

LubeDude

Admiral
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Oct 8, 2003
Messages
6,945
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

Originally posted by JustMrWill:<br /> Anybody wonder if NautiJohn has a search bot running that alerts him to any trim tab question?<br /><br /> :) <br /><br />-JustMrWill
:D :D A sirren goes off in our shops when a trim tab question,(for John), and an oil question for, (Me) comes on the forums. :D :D
 

Tabman

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Feb 21, 2002
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566
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

The QL Interceptors are quite interesting. Interceptors are not a new idea and have been around for quite some time. Mostly their use has been confined to motion control (stabilization) on larger high speed craft such as ferries. They have also been used to steer larger high speed craft. About 7 years ago Don Blount (a really great Naval Architect) gave a seminar re Trim Tabs and Interceptors at IBEX (Boat Builders Trade Show), in which I was also involved. Since then I have read most of the available technical papers on interceptors and have been involved with some of the boat builders we supply Trim Tabs to who have tried them out. They have been mostly “high<br />end” water jet driven boats. The results in the field tend to support the technical findings. Interceptors work very well at high speeds, however not as well at lower speeds. This continues to limit then to large high speed craft. The reports I have also heard recently about recent attempt to use then on smaller boats tend to bear this out as well.<br /><br />This is a problem since one of the main benefits of Trim Tabs is their ability to create lots of lift at lower speeds. This allows the boat to plane at lower speeds, keeping the sharp sections of the bow down, cleaving the oncoming chop. As others have mentioned in this tread, the ability to plane at lower speeds is something that just about boat operator will appreciate.<br /><br />Remotely controlled Trim Tabs like Bennett, Boat Leveler, Lenco, Lectro Tab, etc. will give the greatest amount of control over broadest range of sea conditions, throttle settings, weight distribution etc. Of course I work for Bennett and have a bias towards remotely controlled Trim Tab, Bennett in particular! I will leave the debate to which is better up to the folks at the forum, but I thought I could shed a bit of light on the interceptors.<br /><br />I hope this is helpful.<br /><br />Tom McGow<br />Bennett Marine
 

JustMrWill

Master Chief Petty Officer
Joined
Aug 12, 2003
Messages
877
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

Wow...competing companies monitoring the forums...just to be fair to all...why don't you guys all send me "samples" of your products for my 21' Regal and I will evaluate each and give a product review at the end of the boating season...of course after these have been installed on my boat..you wouldn't want them back..right? :) <br /><br />-JustMrWill
 

stevens

Senior Chief Petty Officer
Joined
May 4, 2005
Messages
799
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

This forum is great! Thank you for all your comments.<br /><br />I'll have to mull this over before deciding which trade-off to make; control vs. convenience vs. cost.<br /><br />Not an easy choice this, and I'd prefer to feel more certain before drilling holes in my boat.<br /><br />Here's my reasoning so far:<br /><br />Smart Tabs: relatively inexpensive ($360 locally), will improve the ride, easy to install and use, no manual control and little compensation for off-center weight loads. I like the idea of constant adjustment, like a car suspension. However, do I really want to have the tabs fully down whenever not planing? Added drag?<br /><br />Bennett et.al.: much more expensive (local prices: $683 for the tab kit, $87 for the auto-retract, $289 for the TPI), much more to install, more that could break, much better manual control, but less easy to use. Could be combined with some automated system, like that of Mente Marine, but this is very costly ($677 for the Bennett ATC, $790 for Mente). Worth the extra expense over Smart Tabs?<br /><br />QL interceptors: intriguing concept - if it works well enough at low speeds. No corrosion problems. Fewer potential mechanical problems. Instant response. Complete package, with trim indicators and auto-retract included, but at a high price ($860 locally). <br /><br />It is not just the gas that is expensive over here! The importer and dealer margins must be fat.<br /><br />I've looked into importing this directly from the US, and there seems to be quite some savings to be had. But then, complicated warranty claims if anything malfunctions. <br /><br />Thanks again! ...and any further comments would still be appreciated.
 

bossee

Senior Chief Petty Officer
Joined
Jul 18, 2002
Messages
727
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

Stevens,<br />If You mount some sort of trim tab system on Your boat, please report back in this forum after You have used it for a while. Would be great to read.<br />Good luck!
 

Jdeagro

iboats.com Partner
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Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

Stevens;<br /><br />Regardless of the trim tabs that you install, deploying them at slow speeds will give you a major improvement in tracking, eliminating the low speed wander. As for creating drag, that simply does not happen. Trailer boats magazine tests indicated some fuel economy improvement at even the slowest speeds.<br /><br />By the way I heard the same reports that Tom did regarding the interceptors, but have had no personal experience. The larger the planing surface the better for low speed performance (wihtin reason).
 

stevens

Senior Chief Petty Officer
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May 4, 2005
Messages
799
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

Hi guys,<br /><br />and thank you for the follow-up, John. You'll be pleased to know I ordered a set of Smart Tabs today from the local Watski dealer.<br /><br />At $360, they were expensive relative to the US price, but at least they'll be in place before the boat goes on the water next Friday (the 13th!!).<br /><br />I have great expectations for these tabs, and will post back after I've tried them out for a few weeks.<br /><br />Thanks again.
 

Jdeagro

iboats.com Partner
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1,682
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

If you have any questions about adjustments or performance let us know. You can email us at info@nauticusinc.com<br /><br />Here are a few tips:<br />1) install them per the directions with all of the adjsutments in the center.<br />2) from this point on you should only need to make the pressure adjustment on the plate bracket, do not change the top bracket (transom bracket) adjsutment. The plate bracket adjustments will not change the angle of deployment, it only chages the pressure.<br />3) the boat should run 2 to 4 mph (3 to 6 kilometers) faster. If it runs slower, reduce the pressure setting until the boat runs at least as fast as before.
 

stevens

Senior Chief Petty Officer
Joined
May 4, 2005
Messages
799
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

OK, the Smart Tabs came on the boat yesterday, and I had my first trial runs today.<br /><br />I also swapped propellers, and this is commented on in a separate thread.<br /> <br />Now, the Smart Tabs first; wow! I am a convert!<br /><br />There was very little bow rise, cleanly on plane at 11-12 knots (vs. approx 15 before), a smooth and stable ride, and the boat keeps nicely level during turns. The small choppy waves presented no problems, and the dampening effect of the Smart Tabs was very noticable. I can probably now cruise at 20-24 knots or more without the kids protesting or getting scared (they're 5 and 7 years old). We now have a much wider speed range available for comfortable cruising (from 11-12 knots and upwards).<br /> <br />There was absolutely no problem trimming the bow up or down using the outdrive trim. The people who worry about not being able to trim the bow up in order to go with the waves, can relax - this is not an issue. The bow can be as high as you like.<br /> <br />There was no problem backing up, the boat then felt just like before.<br /><br />At very low speeds, say 2-5 knots, there seemed to be less wander. But, the Alpha drive is probably never as good as a duoprop drive in this respect.<br /><br />I saw no loss of top speed, but no gain either. The GPS remained at 36 knots at 4300 rpm.<br /> <br />The only thing the Smart Tabs couldn't do was to correct the list resulting from my 270+ lbs heavy mate who sat in the port seat. He then had to sit midships, and the boat ran straight again.<br /><br />Nor could the tabs fully prevent the porpoising motion (i.e. bow going up and down) when I trimmed the drive too far out, at full speed. At lower speeds, and when the drive was trimmed correctly, there was no porpoising at all. <br /><br />Gratifyingly, the effects of the Smart Tabs were just there, on the first try. No need to think about adjusting anything other than engine trim and speed - the Smart Tabs did their job flawlessly and effortlessly.<br /><br />Adding the Ballistic propeller didn't do me nearly as much good. A noticably better accelleration from zero, a seemingly better grip in chop and turns, but also 1-2 knots lower top speed.<br /> <br />All in all, the Smart Tabs were well worth the money and clearly do what they claim. My first impression is at least very positive.<br /><br />Would I buy the same again? The Smart Tabs, absolutely. The propeller, probably not.<br /><br />On a larger boat, operating in rough waters, I would probably go with adjustable tabs, for the possibility of manual & lateral control. But, I would also go with some automatic levelling system to get the same ease of operation. However, this would be many times the cost of what I paid now, and even so, wouldn't offer the same kind of constant "suspension-like" ride adjustment. For my 21' small boat, and with my wish for easy operation, the Smart Tabs seem the perfect solution.<br /><br />Thanks to all of you for your kind input.<br /><br />Oh, it was so nice to be on the water today. The summer time is great here up North, after those long and dark winter months. Happy boating to all!
 

QC

Supreme Mariner
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Mar 22, 2005
Messages
22,783
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

Thanks for the report back!!! Cool.
 

Jdeagro

iboats.com Partner
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Jul 30, 2003
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1,682
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

Stevens,<br /><br />Thanks for the report and I am happy the Smart Tabs are performing the way you wanted. <br /><br />If you reduce the left pressure slightly, you should pick up a few MPH.
 

mattttt25

Commander
Joined
Sep 29, 2002
Messages
2,661
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

john- you meant lift pressure, correct? didn't want him altering just the left tab.
 

Jdeagro

iboats.com Partner
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Jul 30, 2003
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1,682
Re: Smart Tabs, regular Bennett-type tabs or QL interceptors?

Mattttt25;<br /><br />Thank you for the edit - you are correct I meant Lift not left.<br /><br />By the way I will be at the MACC Conference in Norfolk VA all of next week, On Saturday the 21st I will be at the Bass Pro Shops store in MD. If you are arround on Saturday drop by and say hi.
 
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