Trim Tabs

[fishfeeder]

Howde all wise people,

I have ordered a set of Bennetts Trim tabs and have the installing just about sorted in my head and where everything is going.
Except for a small problem I have with the angle of the transom not being square.
The Trim tabs will need a spacer on the transom to square up the angle so the Trim tab will run square with the hull.... (as clear as mud I know)
Other Seafarer Vagabond / Victory owners must have this same problem as the transoms look to have the same steps so I am guessing the angles are the same aswell.

Can someone give me some pointers as to what material I should use and how to put it on to the transom and how do I work out the angle.

Cheers
Brett

[Chimo]

Hi Brett

These pics show the Lencos as fitted to my Vagabond. You can see the extent of spacer (none) used to fit these which work fine.

Good luck you will wonder how you lived without them.:)

Cheers
Chimo

[Chimo]

These are probably useful too
C
C

[Micadogs]

Hi Brett, Chimo's pictures are excellent so use them as a point of reference, especially cutting holes through the steps.

In relation to "squaring up with the hull" - if I understand your question correctly you dont need to do this.

You need to have an even space across the bottom of the tab and hull (as shown in Chimo's second post, left hand picture).

The connection at the tab and at the hull can move approx 270 degrees so it wont matter if there is an angle in the transom.

The tabs work by forcing water under the rear of your hull, not under the tab itself (or the boat lifting on the tab). This is why it doesn't have to be square to the hull.

Hopefully this answers your questions - Chimo pictures are excellent for a visual.

I fitted Lenco's to my boat so dont hesitate to ask any further questions.

You will be surprised just how good they are!!!! I still cant believe it!!!

Regards Adam

[odes20]

Yep just installed Lencos 9x9 same as Chimos.

Just fantastic, and yes I agree just put them on like the pics.
No need to square to hull
John

[fishfeeder]

Thanks guys and Chimo those pictures are great and I had found them before while searching Trim Tabs on this forum. I am getting the extra Short Actuator so no need to cut holes in the steps.

The Tab (M120) looks in there installation video and online seem to have the wings pointing down (into the water). So if they are not pointed straight out the back of the boat they will create spray and be under heaps of pressure and cause drag from the water flowing under the hull.

Chimo when you stand at the back of your boat you will notice that the Trim Tabs point out towards the side at an angle, because of the angle of the transom under the boarding steps..... I also notice in your pictures your Tabs wings point up, this is opposite to the Bennetts Tabs.

This is why I asked how do I make a Shim to straighten the tab so its square, So while under way the water will flow straight under the Trim Tab instead of it flowing at an angel.

Hope this now makes more sense

Cheers
Brett

[Chimo]

Brett

I suspect there may be an ever so slight angled flow under the tabs at really slow non planing speeds; while the tab is probably not active or effective I doubt the even if this occurred at planing / higher speeds it would not appear to be an issue as the tabs certainly work IMHO and a few others who also posted on this thread. In the true Qld idium therefore may I suggest "Dont you worry about that!"

Cheers
Chimo

[Smithy]

I'm with Chimo. Don't worry about it. Tabbing a bit on one side moves you off course anyway so tabbing a bit and putting those little wings into play is no biggy as you would have to correct no matter what.

[fishfeeder]

OK, Sounds like maybe I have over thought this matter. It just seemed weird to me that they were at an angle and I like to do things right the first time.

Cheers
Brett

[johncar]

I don't want to add to the confusion but I like to run my tabs at the correct water flow angle and I know that lamost everyone else doesn't worry about it.

You don't have to have them perfect. Just my OCD to have to have thing running at their optimum.

I have fitted 9" x 12" tabs to two seafarers, my Victory and a friends Viking.
Both sets were wedged to run parallel with the water flow.
On those boats I cut two wedges from a white poly material I bought from a plastics supplier at Lytton. (their name escapes me).
Across the wedge it was 25mm at the widest point to nothing across the width of the 12" tab.
I wouldn't say they were absolutely perfect but very close running nice an parallel when just skiming the water.
Now bare in mind that this all changes as you tab down into the water due to the deadrise at the stern, they start to toe outward and become less parallel.

So if you are really fussy you would have a little toe in when fully up going to a little toe out when say about half way extended.

On my latest boat Tournament 2100, I have also fitted wedges to help correct the angle, see below.
These are even more wedged then on my Victory, from 30mm to nothing.

http://i610.photobucket.com/albums/tt187/johncar/Tournament%202100%20Walkaround/BILD1734.jpg

http://i610.photobucket.com/albums/tt187/johncar/Tournament%202100%20Walkaround/BILD1736.jpg

At the end of the day I figure that there will always be a bit of turbulence and spray from the tabs and I know it is not normally a major problem just fitting them straight on the back but i feel better when I see them running nice and inline with the water flow and minimal water spraying around.

just remember too that the water flow behind the boat at cruising speed is not parallel to the boats keel in either axis. It is both being forced inward and upward.
Regardless in what you decide to do your boat will be so much better for it. Tabs are GREAT!

[fishfeeder]

Johncar,

That's what I was getting at and your pictures and details make a lot of sense to me and explain what I was thinking about.

I am thinking seeing that the tabs will only be down maybe 1-2 inchs when activated so working on that amount it shouldn't be that hard to work out the toe in or out......

Did you just use longer screws to attach the Tab and the Spacer to the hull.

Cheers
Brett

[Chimo]

Hi JC and Brett and other AFs

On those boats I cut two wedges from a white poly material I bought from a plastics supplier at Lytton. (their name escapes me).
Across the wedge it was 25mm at the widest point to nothing across the width of the 12" tab.

I would be very careful about hanging a tab that will experience significant forces, depending on the speed and the down angle, on a semi- flexible item like poly material. I doubt this stuff was ever meant to be used this way, it is usually used as spacer material ie I have it under my fuel tank to keep the tank off the frp tank bed and between the motors and the transom.

If one wishes to fit a spacer as JC has done the spacer should IMHO be a solid / metal object ideally stainless steel.

I still don't see the need for a spacer and neither did Lindsay Fry the then owner of Seafarer who fitted my tabs.

Cheers
Chimo

[Danstu]

Hi

Just finished fitting a pair of Bennetts on my Victory. Didnt use any spacer. The hardest part was cutting the holes in the right spot through the boarding steps. If you want to come around and have a look let me know. I am at Albany Creek.

Cheers











Howde all wise people,

I have ordered a set of Bennetts Trim tabs and have the installing just about sorted in my head and where everything is going.
Except for a small problem I have with the angle of the transom not being square.
The Trim tabs will need a spacer on the transom to square up the angle so the Trim tab will run square with the hull.... (as clear as mud I know)
Other Seafarer Vagabond / Victory owners must have this same problem as the transoms look to have the same steps so I am guessing the angles are the same aswell.

Can someone give me some pointers as to what material I should use and how to put it on to the transom and how do I work out the angle.

Cheers
Brett

[Lancair]

Brett, you have a valid point. I understand exactly what youre talking about with the Bennet tabs and not being straight with the hull and the little side strakes on the Bennet Tabs. One of mine is out of alignment due the hull not being 100% square. It DOES have an effect and After seeing the Lenco tabs with only the slight raise on the outside edge or just dead flat, Im going to take mine off and have the side piece removed, leaving only the slightly raised section to the edge. It has a significant effect on my boat. True, putting one tab down will have a steering effect anyway but I can tell the difference between each side on mine. The right tab pulls the boat more right that the left pulls left. Id try to get them straight or just cut off the bit like Im going to do.

Lancair

[fishfeeder]

After looking at the pictures and reading the replies I have decided to install without the spacer. If the tab seems to be running to weird i will make a spacer.

Danstu, I ordered the shorter actuators (rams) so I don't have to cut holes in the steps.

Thanks for the feedback and help.

Cheers
Brett

[Micadogs]

Hi Guys, adding the spacer seems counterprodcutive to me. If you look at the Bennetts website and others, the tab is meant to push water under the rear of the hull creating a "Hill" (as they call it). The angle of the trim tab creates this hill for it to be effective. By flattening it out, you are now running on the tab itself and will require further down force to push water under the hull.

I would seek independent advice from the manufacturers prior to putting in spacers.

regards Adam

[snatchy]

Fitting instructions for Bennett and Lenco say to fit a wedge or shim so they are parallel to the keel of the boat.

See figure 5;
http://www.bennetttrimtabs.com/pdf/instIcon/trimtab_installation.pdf

Look up Tabman's product page on thehulltruth for more Bennett fitting advise for such situations. Plastic wedges are standard method these days. Depends on the angle as to how much it it needs it.

[fishfeeder]

Snatchy,

I read that to mean the mounting had to be on a Flat surface as the curved surface would bend the tab when installed.

BUT that's were I started thinking about how the angle of the transom would make the taps point out. I sent Bennett's an email asking for there advise over the matter.

Cheers
Brett

[snatchy]

Sorry, yes you are right that link is for curvature. I was on autopilot for a few minutes when i wrote that

if you google you will find some info about using wedges correcting for transom angle as it is a common issue. The edges of your M120's will cause it to be a bigger issue than other tabs, as Lancair mentions. From what i have read it steers the boat but don't know what other issues it causes?

Mine has both curvature and angle to contend with so i have done a lot of research and have some significant work to do to get them mounted adequately.

Bennett has great after sales service and i am sure you will get good advise

[tenzing]

I wonder whether you can overthink these things.
These tabs were fitted by the seafarer dealer to my victory a few years ago.
They go just fine and while there are undoubtedly other good ways to do it , this set up has done hundreds of hours happily for me.
Good Luck with the job
Brendan

PS They are roughly in line with the long axis along the chine.The little dress flange was done at Greens to tidy up the hole in the duckboard

[Chimo]

Hi Brendan

Looks like us Seafarer owners get great boats and extra benefits like straight transoms to bolt / screw things like trim tabs without any extra fiddle with wedges! Winner once again.

Cheers
Chimo

[tenzing]

It looks that way , Doesnt it.
The boat in question is the same I imagine, so it should be straight up and down. The hole on the boards has been absolutely no problem at all. My personal preference is for doing the cut rather than re engineering the rams and fulcrum point, although I did enjoy watching the post of the process last year or thereabouts.
Cheers Mate
Brendan

[johncar]

Johncar,

That's what I was getting at and your pictures and details make a lot of sense to me and explain what I was thinking about.

I am thinking seeing that the tabs will only be down maybe 1-2 inchs when activated so working on that amount it shouldn't be that hard to work out the toe in or out......

Did you just use longer screws to attach the Tab and the Spacer to the hull.

Cheers
Brett

Yeah Brett, look I really don't think it matters that much either way you do it as far as them being effective trim tabs goes.

I only did this to get cleaner water flow and I have seen some that spay a bit of water around. It's not a big deal. Just if you start with toe out it will be more as you apply them and the surface pressure across the tab will be a little less even giving a slightly spongier effect not that I would or could measure it. I just figured that it stands to reason that a plate running as close as practical to the water flow at cruise speed will give the most efficient effect and cleaner running. A few degrees of offset probably makes bugger all difference.

The poly material I used is quite dense and rigid (for plastic) and has been used extensively for making wedges and packing for these types of things on boats.

I have never had any issues with it used in this situation and it is well glued and screwed. I keep a good eye on these things and would notice any problems pretty quickly.
Yeah I do use 3 different screw lengths but probably don't have to as they only screw into the void anyway, but me being miserly 316 SS -50mm x 6mm are dearer than 25mm x 6mm, so I get what is long enough for each part.

The main thing is just get them on there asap and enjoy the difference.

[fishfeeder]

My 2004 Seafarer Vagabond is a fantastic boat and I think its made very well, I just cant see how you would call them a straight trnasom. Anyway by what everyone has stated it probably wont make that much of a difference so I am going to put them on without the Wedge first up as I can add the wedge later without to much of a problem....

Talking about problems, I was going to replace the 4 Brake discs and Calipers today on the trailer, but the Calipers dont match the mounting holes.... So now I am looking at the weather and wondering if I should put the old one back on and just go fishing ??

Cheers and hope everyone has a great weekend
Brett

[tenzing]

My 2004 Seafarer Vagabond is a fantastic boat and I think its made very well, I just cant see how you would call them a straight trnasom. Anyway by what everyone has stated it probably wont make that much of a difference so I am going to put them on without the Wedge first up as I can add the wedge later without to much of a problem....

Talking about problems, I was going to replace the 4 Brake discs and Calipers today on the trailer, but the Calipers dont match the mounting holes.... So now I am looking at the weather and wondering if I should put the old one back on and just go fishing ??

Cheers and hope everyone has a great weekend
Brett
sounds like two good decisions there Brett
Get out and have a good one.
Brendan

[gofishin]

… One of mine is out of alignment due the hull not being 100% square… How far out of alignment? Is it a tinny?


… It DOES have an effect and After seeing the Lenco tabs with only the slight raise on the outside edge or just dead flat, Im going to take mine off and have the side piece removed, leaving only the slightly raised section to the edge… Certain size lencos (12w x 9) were renowned for the tabs bending (mostly port side) as the plate wasn’t thick enough for the size/design of the folds down the sides.


… The right tab pulls the boat more right that the left pulls left… Does it also lean more to the left than right too (when each tab is fully down)? I would say this has more to do with the effect of prop torque than tab alignment – subject to the above! Depending on the boat, prop, motor height & steering tab alignment some combinations give some boats a distinct lean to the left. Others it is hardly noticeable, however prop torque from a standard RH prop will always tend to lean the boat to the port/left.


… It has a significant effect on my boat… The right tab pulls the boat more right that the left pulls left. Id try to get them straight or just cut off the bit like Im going to do… Don’t do it! The folds are there for a reason – they add rigidity/strength to the tabs.
Cheers
Brendon

[johncar]

Talking about problems, I was going to replace the 4 Brake discs and Calipers today on the trailer, but the Calipers dont match the mounting holes.... So now I am looking at the weather and wondering if I should put the old one back on and just go fishing ??

Cheers and hope everyone has a great weekend
Brett

Yeah I had my trailer brakes to pieces last week, Haven't quite finished the little upgrades I was doing but put it all back together today ready for an opportunity to get out this week, Maybe...??
I'm sure it will rain a blow again soon enough so I'll get back to the trailer then.

[fishfeeder]

Just as a follow up, Bennett's got back to my email, and they said "You will need to manufacture some mounting shims for the mounting plates & actuators to ensure the tabs are positioned inline with the water flow for proper operation."

So I have sent a reply asking for more information on how they surgest to do the installation.

Cheers
Brett

[Chimo]

Hi Brett

Just for interests sake how about referring / sending pics of my Vagabond and Tenzing's Victory and the way the tabs are fitted to Bennetts.

Please ask what they would fit or how they would install tabs differently.

Also please bear in mind that mine were fitted by Lindsay Fry who was responsible for the design of both those hulls and owned the company at that time before selling it to the Haines family.

Looking forward to their thoughts

Cheers
Chimo

[stue2]

Hi Brett, Chimo and all. I have fitted my tabs under the steps, they are at a slight angle but there are a fair few set like this and from what info I can soarce it doesnt make much difference or any.

I shifted the tab bracket to the back of the tab on they went.

Full test at easter.

Cheers Stu

[Chimo]

Hi Stu

That is on a Vagabond too isn't it?
Enjoy Jaffa!

Cheers
Chimo

[stue2]

You bet I will. Been too long already. Promise to send a pic if the weather gods dont fight.

will send one anyway.

cheers, Stu

[fishfeeder]

Chimo, Thanks for the offer to sent the photos as I think it will be easier to describe to Bennets.
Bennetts just replied to my email asking for the widest part of the wedge, I guessed it was 20-25mm on the outer edge and nothing on the inside. Johncar does that sound about right to you ??

Stue2, Great news about getting them on, would be good to see your setup. Is it possible for you to take some photos showing how far the Tab points out towards the side.

Cheer
Brett

[Chimo]

Brett

It just occurred to me that if you are fitting tabs to a Vagabond, which I think you are and you are suggesting that the tab points out towards the side rather than in line ie parallel, with the keel then you are trying to fit your tabs too far out from the keel ie not parallel, on the curve of the transom. Refer to my second pic in post 3 above.

Cheers
Chimo

[fishfeeder]

Chimo, This photo of yours shows the angle I am referring to. Notice the angle where you mounted your Tab is different to where the motor mounts, If you put a straight edge on the transom where the motor is bolted and compare that to the Tab mount.

The Text is a bit hard to read and the angles are not correct but gives the idea.
Red line is parallel to the back edge of the Trim Tab
Blue line is Parallel to the Transom (where motor bolts on and 90 degrees to the Keel)


66494

[fishfeeder]

It also shows why Johncar adds the wedge to the Transom to square up the Trim Tab to the Keel/Transom.

Cheers
Brett.

[stue2]

Chimo, Thanks for the offer to sent the photos as I think it will be easier to describe to Bennets.
Bennetts just replied to my email asking for the widest part of the wedge, I guessed it was 20-25mm on the outer edge and nothing on the inside. Johncar does that sound about right to you ??

Stue2, Great news about getting them on, would be good to see your setup. Is it possible for you to take some photos showing how far the Tab points out towards the side.

Cheer
Brett

Yeh mate I can but it will be a day or two.

[Chimo]

Hi Brett

Notwithstanding the angles you have indicated that I need to go look at in the light, the tabs work a treat, do what they are supposed to do and after some 5 or 6 years are still to fall off.

I'll have a look tomorrow, in the meantime it still seems that your over-thinking this, given the way I had mine fitted ie ("Lindsay please fit trim tabs to the Vag as per your recommendations " end quote) and results I have got.

Cheers
Chimo

[Dignity]

Just as a follow up, Bennett's got back to my email, and they said "You will need to manufacture some mounting shims for the mounting plates & actuators to ensure the tabs are positioned inline with the water flow for proper operation."

So I have sent a reply asking for more information on how they surgest to do the installation.

Cheers
Brett


Brett, I know there is a chat board specifically for Bennett trim tabs, I did have the site bookmarked until my PC died and had to buy a new one. This site was also mentioned in one of hte threads on this site some time ago but once again I am struggling to find it. The respondants are Bennetts staff and were quite good. I am spending some time trying to restore my lost data and if I find it I will certainly post it here for you.

[tenzing]

Hi again Brett,
The discussion about the angulation of the tabs away from the long axis of the boat is quite interesting. you are also correct that the mounting section of the transom is some degree away from being perpendicular to the long axis as it is angled fore to the motor mounting section in the middle.
It may also be worth noting that the toe out effect thus formed is further complicated by the fact that the tabs are angled in the other plane too such that the edge closer to the motor has a greater and earlier effect than the outer edge.

You might again look at the photo from my earlier post which shows that despite all this ,the long axes of the tab and the chine are still almost coincident.

Despite all this I think that the overriding consideration is that you can go and physically put your hands on a number of units right here, that have worked for many years and many hundreds of hours, when they were simply bolted straight on the old transom.

You are very welcome to come and take a look any time ,and I am happy for you to give the old girl a run and put the tabs through their paces before you decide whats best for you.

After all the thoretical stuff is settled , I reckon the K.I.S.S. principal is a good one to live by.

Let me know if you want to go for a ride anytime
Brendan





http://www.ausfish.com.au/vforum/attachment.php?attachmentid=66414&stc=1&thumb=1&d=1302249885 (http://www.ausfish.com.au/vforum/attachment.php?attachmentid=66414&d=1302249885)

[Deanom]

Guys,
Sorry to step in late here. I went through this exact problem about 4 months ago when I fitted Bennetts to my Victory.
Dont fit the M120 tabs. You must go for the flat tab and you wont have a problem with the downward facing wing of the M120.
When I realised the problem I emailed a guy from Bennetts and he confirmed I would be better off with the flat tab rather than mounting the winged M120 tab and a fillet. Ended up exchanging the M120 for the flat tabs.
Cant remember the size of the tab (possibly 12x12) but I can get some photos of my setup if you wish.
I went with the extra short rams and fitted the rams under the platform. I had to modify the connection point in the tab but this is not a really big issue.
Very happy with the result and there appears to be no real distubance in the wake from the tabs. Tabs work perfectly and response is excellent.
Also went for the trim indicator which I think is a must. I try and run with my tabs up as much as I can to limit drag and increase fuel efficiency. Without the indicators I dont think I would be able to tell how low the tabs are unless they are causing a fairly noticeable impact on my speed or the bow seems to be hanging low.
Cheers,
Dean

[tenzing]

[quote=Deanom;1272554]Guys,
Sorry to step in late here. I went through this exact problem about 4 months ago when I fitted Bennetts to my Victory.
Dont fit the M120 tabs. You must go for the flat tab and you wont have a problem with the downward facing wing of the M120.

What is the "problem" that you were anticipating.
I havent noticed any problem with the wing itself.
In fact I am surprised that with them attaached in such a way they just go and do what there supposed to. But good to see that most people end up happy with thie setup.
PS .I agree wholeheartedly about the indicators . (and I am sure that comment will open yet another can of worms from the significant group that disagree. )Anyhow , each to his own
Brendan

[Deanom]

Tenzing,
The problem with your setup is the downturn wing not being parallel to the keel which must cause a loss of efficiency (think snow plough).
The batwing shape of the M120 should only be installed parallel and for our sterns between the pod and the chine, this is not possible unless a fillet is added.
I am surprised that your tabs were installed by seafarer. They should of known better.
For your reference, here is the transcript of the email I got from the Bennett representative.

My Email:
" I have just purchased the M120 trim tabs for my 6m Seafarer Victory (Australian fibreglass trailerable boat). On setting up the tab against the rear of the transom, I have noticed that due to the rear transom being stepped, the transom at the chines is about 5 degrees offset from being square to the keel. Due to this I anticipate there maybe a drag/inefficiency issue with the downturns on the tabs. As I do not wish to go to the extra hassle of glassing in a tapered filet, am I better off to return the M120s and swap for the 30cm x 30cm flat tab to avoid the problems with the M120s. What would you recommend."

The response:
"Thank you for contacting us with your situation and yes swapping out the stainless steel trim tabs & mounting plates to our standard 12 x 12's would be your best choice to complete the installation.

If you have anymore questions, please feel free to contact us again.

Regards,
M.J. Thomas
Account Manager
Bennett Marine, Inc.
550 Jim Moran Blvd.
Deerfield Beach, FL 33442
Service hours: 8:00 am - 5:00 pm Monday - Friday (EST)
Phone: (954) 427-1400
Fax: (954) 480-2897"

[tenzing]

Thanks for the transcript.It is spelt out quite plainly by them isnt it.
I was aware that this was their position and I agree on a theoretical level about the efficiency.
On the practical side the tabs will always cause some loss of efficiency due to their drag coefficient ,be that larger or smaller, and mine have been on for 300 odd hours and the loss of efficiency, i would say, has been quite minor( if at all noticeable)
Anyway its all good info, I still think though that even if it works for the wrong reason , it (mine) still works.
Thanks for the info
Brendan

[MikeyS]

Brett

I've had a similar issue withM80's on the transom of my Signature. Only I had to contend with a space of about 50mm on one side, plus a curved transom and a significant back-slope. The transom from hell!

Have a look at what I did at http://s853.photobucket.com/albums/ab97/mpsquires/SHims%20for%20Bennett%20trim%20tabs/?albumview=slideshow
(Photobucket are fixing some problems so you might not be able to access them immediately. Send me a pm if you like and I can email photos to you)
Deanom, you told Bennett that you didn't want to use a tapered fillet, so the best solution was not to use the M120's, which have the "batwing" profile. Bennett have said on other posts that it is important for "batwing" tabs to be perpendicular to the keel-line, as the edges of these are bent 90degrees to the plane of the tab, ie they act like side fins. If these fins aren't parallel with the waterflow, they will be very inefficient. The normal tabs are just flat planes without fins, so it doesn't matter if they aren't mounted exactly parallel to the keel-line. So they aren't saying you can't use m120's on an angled transom, it's just that you should use a shim if you do.

[Deanom]

Thanks Mike,
You are correct. As I told them I didnt want to go to the hassle of adding a fillet, they did confirm that I was better off to go with the flat tab.
Dean

[Dignity]

Brett, don't know if this site helps.

http://www.thehulltruth.com/tabmans-trim-tab-discussion-15/

[johncar]

I guessed it was 20-25mm on the outer edge and nothing on the inside. Johncar does that sound about right to you ??

Cheer
Brett

Yeah Brett,
It was about 9 years ago when I did my Victory Tabs fitup.
I just double checked as I still have the off cut from the material I used and it is 20mm. I cut it in a wedge from 20mm to zero across the 12" width. They seemed to work well at that.

My current boat, tournament 2100, I made 25mm. I may have said 30mm earlier and 25mm for the Victory but just a bit of old timers disease.

There are a lot of angles that come into play and it seems complicated to work it out.
You also need to determine at what point of trim you actually want them to be running parallel because it changes as you go up or down.

I decided that I would try and have them with a very slight toe in when fully up and running parallel with about the first degree of effective trim.

It is very hard to determine the water flow too while in the shed. I found the easiest way is to take the boat for a run with someone else at the helm, carefully go to the stern at cruising speed on calm water and running straight. Eyeball the water flow with a straight edge, looking straight down to approx where the tab will be, just a piece of timber will do and put a pencil line on to somewhere on the stern as a reference for later. Just don't rub it out.

So then all you have to do when home in the shed is to set up the tab in place, think I used a short plank with a jack pressing up lightly under it extending a bit past the stern enough to sit the tab on and then angle it around while sighting it with the stick you used earlier placed back on your reference marks while on the water. Line it up again and look down at the tab and set it where it looks parallel, or you could slightly toe in.

The water flow is not parallel with the keel out near the chine where the plates are to mounted and the further you go out the more the angle of the flow.
When mounting on a boat such as a CruiseCraft 625 with a straight across transom and mounting tabs with no wedges you are in fact mounting your tabs with toe in , because the transom is angled at about 12 degrees to the vertical, looking straight down it forms a shallow Vee and this is also what you are doing by installing the wedges on a transom that is angled like the Seafarer or my Tournament and many others, so then when looking straight down you get a straight line across the boats width more or less where the transom meets the bottom.

That's probably as clear as mud but I hope you get my drift, but as I said before many just plonk them straight on and they work fine for them and the loss in efficiency may be negligable.

Or just plot that water flow angle and take it as being correct and set them at that fully up and you will be close enough.

I should mention too that I have only ever mounted either flat plates or ones with a slight turn up.
I would be concerned that any significant downturned tab may affect steering if running with just one side or the other down to any degree by being angled outwards. It would seem that efficiency would be affected too if not running at the best angle, as they would be fighting each other and or the engine for not only lift but direction as well. although I see some comments here that they have no problems and that may depend on the boats weight and power fitted, maybe other factors, not sure but i would think that it would have to have some effect.
I feel my motor load up as I apply just flat tabs running fairly parallel.

Flat plates may be the go anyhow.

[fishfeeder]

I am going to have a go on the weekend to fit them up, I am going to start with the 20mm wedge and see how that works, If it needs to be changed later I can.

I will take some pictures as I go and post them on here.

Cheers and thanks for all the help and Ideas

Brett

[fishfeeder]

Mikeys, Just got Photobucket to work and nice job. That would have drove me nuts trying to that work out, But its given me confidence to get in and do mine.

Cheers
Brett

[matt fraser]

Great thread, thanks for all the info from everyone. I'm installing tabs soon too, so this is very usefull.

Just checking to make sure you guys are sealing up all those screw holes properly. I've seen what happens to a transom when water gets in. I'd be drilling the holes out oversize and filling them with resin before redrilling the holes to suit the screws.

A bit of extra work, but cheaper than replacing a transom in a few years time.

Matt

[MikeyS]

Mikeys, Just got Photobucket to work and nice job. That would have drove me nuts trying to that work out, But its given me confidence to get in and do mine.

Cheers
Brett
Brett
I probably should mention that there was more than one quiet ale consumed, sitting on my butt, staring a the transom, over a period of several weeks thinking how the hell I'm going to do this. Not quite as easy as the instruction manual.

If you can get away with using a single piece of Starboard (you might like to try buying from here http://www.buckwoodcraft.com/king_starboard.htm#Quick%20Overview%20Price%20Char t ) At one stage I was contemplating using starboard and getting these guys to cut it with their bandsaw. I used plenty of cardboard templates and duct tape to get the angles right with mock-ups. The thinking bit was the hardest. When it comes to fabrication, it's all just one step at a time. Good luck.

Matt, definately sealing the screw holes. Makes the final assembly exciting when there's different types of goop hanging of all sorts of bits and pieces, trying to keep everything clean and neat before it's all tweaked up.

And countersink any holes drilled, too!

Mike

[fishfeeder]

Anyone know where I can Buy Starboard or ????? in Brisbane Southside ???

Cheers
Brett

[stue2]

Hi all.

Just got back from the beach and had a good test on the new tabs.

They are mounted flush to the transom and so turn out a bit. They are M80's batwing.

The boat is a Seafarer Vagabond with twin 90 etecs (but this is not about etecs). They are not counter rotating.

The tabs worked a treat and with no noticable effect on steering. That is the boat did not want to turn in big circles. It did not want to veer to port.

I ran the speed test without the tabs and with for a 1 km/h change (63km/h v 62km/h) so this is not an issue to me and i never ran both ways.

The tabs did just what they were supposed to do, unless of coarse I dont know what I'm looking for.

We had 5 on board one day and three another so the weight was up with all the gear and people.

It could be that twin legs may be enough to counteract any steering problems that could have been.

Cheers, Stu

[Chimo]

Hi Stu

Now all you need to do is fit foils to the motors and you can lift the bum another inch or so up and really enjoy the "Vee"

Good to hear the tabs did the job, on mine they added to the bum lift even when they were full up. The foils went on first and there was a noticable bum lift as witnessed by the fact that the rear side spray pattern was lessened and also moved further rearward.

This was good esp when traveling at a slow plane side on to stiff breezes the spray no longer can occasionally, as it previously did, get into / onto the rear seat and the four batteries and two oil storage bottles.
Maybe there is a little weight back there, not to mention the two 115 HP Evinrudes at about 167kgs each!


Cheers
Chimo

[tenzing]

[QUOTE=stue2;1278125]Hi all.

Just got back from the beach and had a good test on the new tabs.

They are mounted flush to the transom and so turn out a bit. They are M80's batwing.

The boat is a Seafarer Vagabond with twin 90 etecs (but this is not about etecs). They are not counter rotating.

The tabs worked a treat and with no noticable effect on steering. That is the boat did not want to turn in big circles. It did not want to veer to port.

I ran the speed test without the tabs and with for a 1 km/h change (63km/h v 62km/h) so this is not an issue to me and i never ran both ways.

The tabs did just what they were supposed to do, unless of coarse I dont know what I'm looking for.

We had 5 on board one day and three another so the weight was up with all the gear and people.

It could be that twin legs may be enough to counteract any steering problems that could have been.

Cheers, Stu[/QUOTE

Geez Stu. That's bound to get it all started again!
I'm glad to hear that yours also work fine without the fillet.
Again I can see the logic in the fillet, but they really do work fine without( on my boat )without noticeable loss of speed or increase in fuel usage , and the boat definitely steers straight.
Here we go.
Brendan

[stue2]

Ha. Yeah it might get em going but it was a good read and some good pics as well.

Yep chimo I'm looking into foils. I have heard of one on each side. stay tuned.

Brett if you see this I'm working on a pic or two for you just got a small camera problem at the present.

Cheers, Stu

[Chimo]

Hi Stu

"I'm looking into foils. I have heard of one on each side. stay tuned."

When Lindsay at Seafarer fitted my Lencos noticed they had fitted foils to a twin motored Vag with only one foil on the outside of each motor. Mine already had a full set on each and the difference had been observed over a number of trips. I asked about the alternative and seem to recall the response was related to cheap. Same thing as to why tabs were not fitted as standard given their benefits.

If you want slower planing and to gain extra bum lift why wouldn't you fit foils to each side of the motor and also get a better balanced result?

Cheers
Chimo

[stue2]

I just thought that one on the outside would be the one thats on the water.

I think you can get them to fit without drilling holes in the cav plate now. Which would mean one on each side of each motor.

My mechanic is trying to talk me out of them.

So I shall research them for a while and yes I know you like yours Chimo.

I have lifted the motors a hole and I think i need to go another so I'll do this first.


Cheers, Stu

[fishfeeder]

OK guys I just wanted to let you all know I finally pulled my finger out and Installed my Trim Tabs and thanks to all who offered there advise. I ended up getting Bennetts to replace my M120 planes for flat planes so I never had to make a Fillet/wedge.

Well the installation was a nightmare with one problem after another with mounting the Top Ram to the transom. The major problem was that the shorter ram's top mountings lined up with the level of the step so after trying everything possible I ended up having to cut holes in my steps. This caused the problem of what should I use to cut the holes in the step as the shape needed to be a half moon. I thought a air Die Grinder with a Fiberglass cutting bit would work, well it did but was way to hard to control. Then I thought of a Dremal die grinder, well this thing was fantastic and cut perfect and sanded even better, it Just took hours to get them to sit perfect.
Ok next problem was how do I drill the holes for the top mount with the step in the way.... another trip to Glenfords Tools, well the young bloke there was fantastic and was really helpful, ended up with a 12inch extender for my drill with all the bits and pieces needed . After getting this it was pretty simple to drill the holes and seal it and screw it all to the boat.

Next problem was with the Hydraulic Pump trying to find somewhere to install it that would hold it flat, to do this I needed to make a wedge and screwed it to the transom... Hooking up all the wires and the Hydraulic lines was pretty straight forward.

Fitted the controls to the dash was simple except for trying to work out which wire on the key to use for the Auto Retract without a test light, ended up and wired it to a switch on the dash for now but will need to get that sorted ASAP.

Next problem was I forgot that I would need to add more fluid to the Hydraulic pump after bleeding the system, mounted it about 5mm to high to get the cover off, SO had to remove it from the transom to top up the fluid level then screw it back onto the transom...

OK so Yesterday was my first outing after installing the Trim Tabs and it was a good test day with it blowing a constant 15-20 knots and I have to Agree they work fantastic at leveling the boat from wind or weight in the boat. But now I am getting cavitation when in messy condition (prop slipping and motor reving up but no forward propulsion).

I am planing on going to Solas Props in the near future to get a new prop to lower my offshore speed and I hope fix my cavitation issue.

I will put some pictures of the installation up as soon as I get the photos off the camera.

Cheers
Brett

[Chimo]

Hi Brett

Sorry to hear about your fitting issues. I guess I took the easy way out by getting Seafarer (Lindsay Fry) to recommend the most suitable units and then stick them on.

Re your cavitation, I found that even when my tabs are fully up they have the ability to lift the rear of the boat higher in the water when cruising etc. It may just be that you had your motor was set at the ideal height before the tabs were fitted and you may now need to go down one hole. Thoughts?

Cheers
Chimo

[fishfeeder]

Yeah the motors height was right before I added the Trim Tabs.
I have been putting of getting another prop as I was wondering if the Tabs would effect the motors height.

I had a bit of a play on the water with them and they make a fair bit of difference to the ride and only having one side down to level the ride does steer the boat in that direction a bit, but its nothing to worry about. Can't wait to get out in a bit better conditions to really see how they go.

Cheers
Brett.
PS, your photos helped out heaps, thanks again for posting them.

[fishfeeder]

I have been having a few problems with corrosion....

First it was the White box where the blue main cable from the controls plugs in.. it corroded off one of the small pins, had to buy a kit to get a new white box..
Now the pump has seized, which Bennetts replaced with no charge to me..

I have to say that Bennetts service has been Fantastic with helping problem solving and replacing the pump.
I don't want have a problem with the Bennetts Tabs just the corrosion issue that I want to fix

What are you guys doing to stop the CORROSION ???

Cheers
Brett

[MikeyS]

Geez, I thought I recognised this thread from many moons ago!

Can't say I've noticed any problem with corrosion, but I have tucked the pump and box up out of the way of spray, deck wash, etc. I usually give all electrical connections a bit of a smear with Vaseline before connecting. But now that you've mentioned the problem, I might just check. Trouble with locating stuff out of harms way- it's also harder to access for inspection.

[fishfeeder]

I had strayed all connections with lanolin and that never seemed to work very well...

I am very careful with the deck wash and only use it if really needs it.. and its not sprayed anywhere near the pump..
I had even put the white box in a Tupperware to try and stop it getting any spray when I replaced the last one..

Never heard anyone using Vas.. but if it works I will see if I have any..

Cheers
Brett

[Chimo]

Hi Brett

Sorry to see you are having issues. Apart from regular replacement of the pump etc due to corrosion there is another option that you may consider..http://www.lencomarine.com/index.php/products/bennett-retrofit-kits-12-and-24-volt .....http://www.ebay.com/itm/Lenco-Electric-Retrofit-Kit-Bennett-Trim-Tabs-15064-001-/140507713943

Cheers
Chimo

[fishfeeder]

When the Bennetts work they are fantastic, I just need to stop the corrosion issues !!!

Bennetts replaced the pump for FREE... so can't complain about there service

Cheers
Brett

[ozscott]

Never had corrosion issues with the Bennett pump. This is the first I have heard of it. Where is pump located?

[Smithy]

Gotta say with 5 years of commercial use of Bennetts I have had no major issue with corrosion on either of my Bennetts. Sure I have had them looking a sad with a bit of green death but a bit of spray and they were all good again. I have done a couple of solenoids. Get onto Captain Rednut on here if you ever do one. It is a simple fix. It is hardly ever the whole pump motor, more the solenoids. I must have a tiny little leak on my 2003 boat that has lived in the water since 2003 and it is the bit of saltwater in the sytem that must have upset my last solenoid. I also picked up a 2nd hand pump cheap as from a chandlery shop that does 2nd hand stuff so I have one sitting there ready to change out at a moments notice if I need to.

[tenzing]

Mine on 3 or 4 years.
Pump and box get spray from time to time, never a problem.
Had a switch go once but that was it.
Cheers
Brendan

[Deanom]

Guys,
No problem with corrosion here also. My pump is mounted up behind the rear seat rest in the victory. I dont spray water up behing the area during washdown and reverse back reasonably into a 20-25knt breeze out wide so see lots of salt coming over the back.
All in all the bennetts have been a good experience for me.
Regards,

[stue2]

Where have you got yours mounted Brett. Mine is well up under and behind the transom seat. Same as Deanom. Vaseline is the go as it is thicker and will stay in place.
As I have noted on another thread, the problem I have is salty damp condensation. So now a real good airing is what I do before winterising.

Cheers
Stu

[fishfeeder]

I have it installed onto the transom as high as I can get it (I have to remove to add oil if needed)
There is no room behind the back seat rest because I have my deck wash and shower pumps as well as my water separator and the Fuel flow for the Lowrance and the switch for the batteries...

I am very careful not to spray the area with the deck wash and when I get home the boat gets a good wash out with fresh water.

I guess I need to be even more careful !!!

[stue2]

Sounds like you are doing all you can. The vasaline in the connections and a spray with lanoline is what I use and all looks pretty good. allthough i havent looked for a couplr of months

[tenzing]

Gus my pump is FLOOR mounted behind where the seat would go if I had one.
I have a kind of curtain of bimini canvas sailtracked on to the back rest and pulle tight at the bottom corners . that keeps out most spray etc.
I wash with fresh ( not every trip) under there, but always leave curtain lifted between trips to air.
Cheers
Brendan
ps. white box is cable tied up fairly high on some control cables

[gofishin]

You could also try ‘CRC Battery Terminal Protector (CODE5098)’, which is a fantastic product. Sprays on to a tacky yellow goo consistency but dries off (mostly) aftera day or so. It says it is “highly resistant to salt water and salt spray” –which I can vouch for 100%, and no re-application required (for years) unless youdisconnect it etc.

Have been using it for 7 years (on two boats) on all sortsof pumps/connections/exposed switches/terminals/things which rust/corrode etc and it is brilliant. A far better product then either Vaso or LanoI believe, however I suppose you could also Vaso the connections beforeapplying this stuff!
Cheers
Brendon

[fishfeeder]

All installed again and working perfect...
Gofishin, I will grab some of that spray and give it a try.

Cheers
Brett