QL v Bennett trim tabs? Answer = Bennetts best for deep V hulls.

In September last year I took delivery of our new 7.5m Origin Evolution platey (23 degree dead rise), complete with Lombardini diesel stern drive. While I loved the new boat I found it a bit of a pain to maintain side to side trim. I had spec'd the 450mm QL trim tabs for the boat and these did work in so far as leveling the hull, but when I corrected the steering after adjusting trim the boat would fall to the other side. This would continue to varying degrees depending on the sea state and our angle of travel.

I discussed the problem with Col and wondered if Bennett tabs would correct the problem. In my mind having a large plate type tab would be more likely to "hold" the hull in position once level trim was achieved. Col agreed with my thinking and in February Col supplied me with a pair of 450mm x 200mm Bennett tabs. I got to work removing the QLs. To cover the holes through the transom from the QLs, Col cut me a pair of alloy plates that I simply sandwiched between the hull and the Bennetts. The mounting bolts went through both and a liberal application of Sika sealed them off. Fitting the Bennetts was easier than I had expected.

Since fitting the Bennetts I have done about 25hrs of running in some very ordinary conditions and the difference in performance is amazing. They pull the bow down a lot harder when running into a head sea than the QLs and they keep the hull a lot steadier when running across the swell. I know that there are many people very satisfied with their QLs, and it was this feedback that lead me to fit them in the first instance. However given the dramatic change I have experienced I thought I would share with you all.

Regards,
Dave.

PS, here is a link to the build thread of Alchemy http://ausfish.com.au/vforum/showthr...-%96-the-build

Attachment 69138youve just confirmed my belief dave,ive actually broken bennets on a previous boat [v19r]
so i went with dana billits this time,the bigger the tab the better imop

Interesting Dave, different boats I s'pose

Had the 450 QL's on the 19C for 2 or 3 yrs now, I recon it's the best money that I have spent on the boat.

Good to see that you have something that works now, I think good tabs are mandatory on deep V boats, makes them soooo much better.

Awesome boat you have by the way.

Cheers

Bill

i think that the ql's should have half the movement for each press, I recon that 1 hit can be too much trim. I found this with both my Seafarer and this boat. Anyone else agree??? In a trailer boat though I find that small changes in sea and wind need constant trim adjustment, with the QL's i feel they should move half the amount per press. Yes they work, maybe over work?

Hi Dave

The Lencos on the Vag perform in much the same way as the Bennetts on yours and you have confirmed the effect of the large flat plate to achieve lift and leveling vs the effect of an item that mainly adds drag but not not lift as such. This was why I fitted lencos in the first place.

Thanks for the update, no doubt it was good for your boat builder to hear the feedback too.

Cheers
Chimo

Thanks for the "heads-up" earlier Dave.

I fitted the Bennetts and they are great. I have done about 15 hours with them and they not only level really well they also stop the boat dragging arse at 15 to 20kph and as such make it a lot easier to control speed and trim when trolling.

Make for a much more comfortable and drier boat with even heavy movements of load onboard.

One trip back across Hervey Bay in a very stiff breeze and choppy sea had 5 people on one side of the boat to keep out of the wind driven spray - the tabs accounted for this admirably.

They say 4 hours to install - took me over two days - but very happy with the outcome.

Quote:

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Originally Posted by OPTI

Attachment 69138youve just confirmed my belief dave,ive actually broken bennets on a previous boat [v19r]
so i went with dana billits this time,the bigger the tab the better imop

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Thanks Opti. I remember seeing your post on your rig when those tabs went on. They are an impressive looking bit of gear, but then so is your whole outfit. A truly beautiful boat

Quote:

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Originally Posted by Vitamin Sea

Interesting Dave, different boats I s'pose

Had the 450 QL's on the 19C for 2 or 3 yrs now, I recon it's the best money that I have spent on the boat.

Good to see that you have something that works now, I think good tabs are mandatory on deep V boats, makes them soooo much better.

Awesome boat you have by the way.

Cheers

Bill

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Hi Bill, thanks for your feedback. A mate of mine has the QLs and he is happy with his too.

Quote:

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Originally Posted by Captain Seaweed

i think that the ql's should have half the movement for each press, I recon that 1 hit can be too much trim. I found this with both my Seafarer and this boat. Anyone else agree??? In a trailer boat though I find that small changes in sea and wind need constant trim adjustment, with the QL's i feel they should move half the amount per press. Yes they work, maybe over work?

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Yes, the QLs are sensitive, but this wasn't the cause of my problems. I ran the boat for 75hrs with the QLs. The fact is they couldn't hold the side ways trim on my boat.

Quote:

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Originally Posted by Chimo

Hi Dave

The Lencos on the Vag perform in much the same way as the Bennetts on yours and you have confirmed the effect of the large flat plate to achieve lift and leveling vs the effect of an item that mainly adds drag but not not lift as such. This was why I fitted lencos in the first place.

Thanks for the update, no doubt it was good for your boat builder to hear the feedback too.

Cheers
Chimo

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Thanks Chimo. I haven't used the Lencos but would assume they'd produce a very similar outcome to the Bennetts. Yes, Col was very appreciative of the feedback and very supportive in helping me resolve the issue.

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Originally Posted by TREVELLY

Thanks for the "heads-up" earlier Dave.

I fitted the Bennetts and they are great. I have done about 15 hours with them and they not only level really well they also stop the boat dragging arse at 15 to 20kph and as such make it a lot easier to control speed and trim when trolling.

Make for a much more comfortable and drier boat with even heavy movements of load onboard.

One trip back across Hervey Bay in a very stiff breeze and choppy sea had 5 people on one side of the boat to keep out of the wind driven spray - the tabs accounted for this admirably.

They say 4 hours to install - took me over two days - but very happy with the outcome.

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Hi Trev. Glad to read you went with the Bennetts and to read you are getting out and about in the new boat.

As a matter of interest, I had the M120 Bennett Sport Tabs on my last boat and they were awesome for the 5 yrs and 500hrs of use I had from them. The reason I went with the QLs on this boat was their compact design and the reports of how effective they were. No doubt they work well on some boats, and the other factor is that we all have different expectations and perspectives of what "good" looks and feels like in a boats handling. I guess I'm fortunate to have been able to try the different tabs on the same boat.

Regards,
Dave.

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Originally Posted by Alchemy

(23 degree dead rise), complete with Lombardini diesel stern drive. While I loved the new boat I found it a bit of a pain to maintain side to side trim. I had spec'd the 450mm QL trim tabs for the boat and these did work in so far as leveling the hull, but when I corrected the steering after adjusting trim the boat would fall to the other side. This would continue to varying degrees depending on the sea state and our angle of travel.

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The Whittley Cruisemaster (sterndrive) is also prone to this lateral stability issue, especially after coming up from displacement to planing mode, but is easily rectified by installing a Stingray hydrofoil (no other brand), which takes pressure off using the tabs all the time.

Agree that the Bennetts are great gear.

Having never owned a bost with trim tabs I just wonder if the Lencos/Bennetts style tabs start to show there ability (due to the larger tab foot print) on hulls over a certain degree dead rise (say 18 deg), while the QL's are better on shallower degree dead rise.
Just a thought.:-?

Running QLs on my Fisher (23 deadrise), wouldnt go back to Bennets. Ran M80s on my old Sportfish so have used both.

I have said it before and I sound like a harp...but have a look at the Tabman's discussion over on the hulltruth.com and you will see backup on Bennets like no other. Over the years it has impressed me no end.

Cheers

Thanks Dave for the comparo. I have never used QLs but often get asked my opinion from friends with boats, what is best?
I guess I have stuck with what I know works well and it just seems to make sense that the large planing surface of the plates on Bennett, Insta Trim, Lectra Tab, Lencos, (had them all) give good lift and infinite touch control.
I have had a good run with any of the above but found the Electrics a little easier/faster to fit and seem to have a faster response time. I do like the extra noise the electrics make because I can hear them operating.
I would not hesitate giving the QLs a go too where there is insufficient room for conventional plate/ram set up, but I would stick to the norm where I could.

I have Lectra Tab currenty and have also owned a previous set and good all round performance too and super effective.

I use my tabs for side to side boat leveling in normal changing load and wind conditions, and usually use the engine for fore and aft trim in moderate conditions. But in extreme conditions into a nasty head sea I will run both tabs down to hold the bow tighter into the waves.

Any trim tab is better than no trim tabs, and just wouldn't go to sea without them.

When I put QL's on my CC685 I went for the 300's, because I felt that one push might have too much effect on the 450's. I found the 300's to be fantastic. Lovely control, pity I didn't keep the boat.:(

But your resolution Dave is another cat in among the pigeons on which tabs to fit! It would be interesting to see if 300's made a difference to you, but when do you stop spending $$$?

Cheers,

tim

I have often wondered about the QL's when side on to the sea. All tabs, both QL blades and anybrand tabs work by pushing water under the stern and that provides the lift which in turn pushes the bow down. (look at any manufacturer's website for this)

When running into a sea then the bow and stern are going up and down and the blades or tabs are able to push water under the stern. When running across a sea I would only imagine that blades loose some of their effect as that motion would not allow the blade to be pushing water under the stern. The tabs would still be effective as they are on top of the water and can still maintain what that are supposed to do.

This is a theory only, just wondering if the poeple with QL's find them more effective in calmer water and when heading into a sea (instead of across it)???

For the record I have lenco tabs fitted to my boat. (I wanted QL's but have a foam filled hull and installation was going to cost more than the tabs)

Regards Adam

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Originally Posted by Micadogs

For the record I have lenco tabs fitted to my boat. (I wanted QL's but have a foam filled hull and installation was going to cost more than the tabs)

Regards Adam

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Same in the CC. I invented something that cured the issue, they were easy enough to fit. Happy to expand on it sometime...

Cheers,

Tim