Need Help With Too Small Trim Tabs

[ippa2]

I actually live in Marion. I live off the east side of the harbor, so across the harbor from Tabor. Great spot. I race Shields out of Beverly Yacht Club, but when it comes to boating with the family I get on the Sea Ray. The wife is not interested in turning winches or dealing with sails. But I do love sailing. I also own a 23' O'day Tempest to bounce around Buzzards Bay in. When I'm not on the Sea Ray.

 

[Tabman]

I graduated from Tabor in 1976. Back then they had a couple of Shields we used to match race, sailed 420s on the sailing team too. Did lot's of one design and offshore racing for many years, ran a sailboat supply and rigging shop in my twenty's.

Marion and Buzzards Bay are just wonderful and hold a special place in my heart. Nice to touch base with a sailor.

Let me know if I may be of any help with your Trim Tab project.

Tom

 

[Yachtmaster.]

[FONT=Verdana, Arial, Helvetica][FONT=Verdana, Arial, Helvetica][FONT=Verdana, Arial, Helvetica] My 1999 330 Dancer is pathetically under tabbed. I believe they are 22X9. I cannot fit 33X9 tabs on the current setup. Has anybody modified their tabs to provide more stern lift?[/FONT][/FONT][/FONT]

I have. Because of the tunnels you're going to need to make the trim tab longer. There isn't enough room to make them wider. You'll need to double the sq.in to be effective. They look huge on the boat but man do they work nice. I had mine made by a sheet metal shop and bolted to the existing tabs. I had the shop bend each side down about 1" That really improved directional stability, I can hold course much easier. I believe they were 23"x20". PM me if you'd like more details.

 

[twoislands]

Just got a 330 and really needs bigger tabs, nice to find others who have discussed this. Your solution seems in line with my thoughts before seeing the threads. Are you still happy? Do you have more thoughts? thanks - Herb (twoislands)

 

[dpmulvey]

Just got a 330 and really needs bigger tabs, nice to find others who have discussed this. Your solution seems in line with my thoughts before seeing the threads. Are you still happy? Do you have more thoughts? thanks - Herb (twoislands)

Herb,

I am still quite happy with the mod. It's night and day handling even to those who have 330's with the original tabs and and have then driven mine.

The ONLY TWO downsides I know of is you have to remember how much steel is back there. One can easily over compensate. I have to adjust at the beginning of each season. There is nothing bad about it per say, you just have to remember you are driving a boat with entirely different handling characteristics. Additionally, make sure that are fully retracted prior to pulling into a slip to avoid undue stress on the assembly.

I can cruise at the same 22 knot at a lower RPM, flatter in the water while using less fuel.

In the 2 years they have been on, I have probably saved the cost of fabrication in fuel alone.

HTH

 

[MikeM]

Hi, "Two"!

Just got a 2001 400DB and was surprised by the small size of the standard tabs! The "K - Planes" on my little 27' Fountain are much larger - and lnger then they are wide - with amazing effectiveness.

Mike

 

[twoislands]

Thanks for the help. Bennett also suggested a size of 12"x22" with 3" ears turned down on the 2 edges. They were very helpful and this seems within reason and for about $150 each side maybe a good start. Though I thought contacting some local metal workers I could get some made and weld them on and likely just a touch bigger. Guess over the next few weeks I'll have made a choice and will drop a note here with my findings. Also just purchased a Garmin 720s Chart Plotter with radar which will accept input displays about the tab's angle. I like to boat year round, the radar should help spot items in the water we don't want to hit during early darkness times of the year. Which bring up additional thoughts about adding spot lights and threading the wires forward.

Cheers, Herb
"Double Vision"

 

[electricaldoctor]

Also just purchased a Garmin 720s Chart Plotter with radar which will accept input displays about the tab's angle.

I am interested in upgrading from my 545s to the 720s unit. So as not to highjack this thread, would you please PM me with more info about how the 720s unit will display the trim tab angle?

regards, Ken

 

[dpmulvey]

Thanks for the help. Bennett also suggested a size of 12"x22" with 3" ears turned down on the 2 edges. They were very helpful and this seems within reason and for about $150 each side maybe a good start. Though I thought contacting some local metal workers I could get some made and weld them on and likely just a touch bigger. Guess over the next few weeks I'll have made a choice and will drop a note here with my findings. Also just purchased a Garmin 720s Chart Plotter with radar which will accept input displays about the tab's angle. I like to boat year round, the radar should help spot items in the water we don't want to hit during early darkness times of the year. Which bring up additional thoughts about adding spot lights and threading the wires forward.

Cheers, Herb
"Double Vision"

IMHO, 12*22 is not going to be enough. My reasoning follows and is simple math. I have no engineering or physics background beyond what was required in school.

33 foot boat = 33 inch span recommended by Bennett.

AFAIK, Bennett makes 2 chord lengths. 9" and 12".

For a 9" tab = 33*9 = 297 square inches per side minimum.

For a 12" tab = 33*12 = 396 square inches per tab.


I (we) only have 22 inches to work with.

We already know 22*9 (198 sauare inches) is not near enough.

While a 22*12 (264 square inches) will change the planing attitude becaure of the length, however my simple math says on a per square inch basis is still not a large enough tab.

I went to a 22*18 = 396 square inch tab per side. The trailing edge is turned up about an inch to stiffen the tab span so my effective wetted surface area is 22*17 = 374 square inches.

I too have the down turned sides. They add a great deal to tracking truer at slower speeds.

HTH.

 

[Plane 2 Sea]

I posted pictures of our '96 330 'Dancer trim tab mod last year, search thread for details... made all the differance in the world..

 

[larrytbull]

so, I have been wondering from all you that have welded on new sheet metal, did you consider just bolting on an extension by using one of the Bennet 22x 12 trim plane only tabs with the down fin, and moviing the mounting point to 6 inches so effective chord is 18" , trying to find an easy way to extend tabs, without a machine shop and welding involved and the price i got from bennete was about 130 per plane, with down fins
the guy at bennett said I could bolt on an extension, but could not guarantee results past 12 inches.
Since most of you guys have used over 12 inches, I am ok with that, just looking to see if there was any reason why no one took that approach

thanks

 

[dpmulvey]

so, I have been wondering from all you that have welded on new sheet metal, did you consider just bolting on an extension by using one of the Bennet 22x 12 trim plane only tabs with the down fin, and moviing the mounting point to 6 inches so effective chord is 18" , trying to find an easy way to extend tabs, without a machine shop and welding involved and the price i got from bennete was about 130 per plane, with down fins
the guy at bennett said I could bolt on an extension, but could not guarantee results past 12 inches.
Since most of you guys have used over 12 inches, I am ok with that, just looking to see if there was any reason why no one took that approach

thanks

Straight replacement was not large enough based on my simple math which may or may not have been accurate in the first place. The longest plane they made at the time was 12".

If the approach you meant was bolting on an existing plane to mine and extending beyond the 12", I honestly never thought of it. My way was cheaper for me. I paid about $375 for the pair built and mounted.

Mine are close to 1/4 inch thick. All the original tab is providing is a platform for the actuator.

I used to have a Regal 2465. A fellow did this with his Regal to cruise nose down at a lower RPM. He used several 316 grade stainless bolts and nylocks to hold his arrangement together with no problems, so yes it can and has been done without welding.

If you want to go 18" out total, you will only have a 3" lateral strip holding the thing together. I would think that would be a lot of concentrated stress when you dropped the tabs. I could be completely wrong and it would not be the first time.

If you are willing to go out 6" to 15" total, I think you would be OK. You have 1/2 the new tab holding the application in place. I am assuming you are going to place the new tab on the bottom of the old. If so, I would feather the leading edge with 5200 to cut down turbulance of an abrupt right angle.

My 2 Cents. Good luck.

 

[larrytbull]

Straight replacement was not large enough based on my simple math which may or may not have been accurate in the first place. The longest plane they made at the time was 12".

If the approach you meant was bolting on an existing plane to mine and extending beyond the 12", I honestly never thought of it. My way was cheaper for me. I paid about $375 for the pair built and mounted.

Mine are close to 1/4 inch thick. All the original tab is providing is a platform for the actuator.

I used to have a Regal 2465. A fellow did this with his Regal to cruise nose down at a lower RPM. He used several 316 grade stainless bolts and nylocks to hold his arrangement together with no problems, so yes it can and has been done without welding.

If you want to go 18" out total, you will only have a 3" lateral strip holding the thing together. I would think that would be a lot of concentrated stress when you dropped the tabs. I could be completely wrong and it would not be the first time.

If you are willing to go out 6" to 15" total, I think you would be OK. You have 1/2 the new tab holding the application in place. I am assuming you are going to place the new tab on the bottom of the old. If so, I would feather the leading edge with 5200 to cut down turbulance of an abrupt right angle.

My 2 Cents. Good luck.

thanks for the info, do you have any of the orignal design plans for your tabs, talking to a sheet metal guy as well and his price seems to be cheaper than the bennet tabs, to do a full sheet

was looking at the pictures u posted, did you leave both side edges turned down or is one up and one down?
any particular reason you chose the combo you chose

 

[dpmulvey]

thanks for the info, do you have any of the orignal design plans for your tabs, talking to a sheet metal guy as well and his price seems to be cheaper than the bennet tabs, to do a full sheet

was looking at the pictures u posted, did you leave both side edges turned down or is one up and one down?
any particular reason you chose the combo you chose

The plans I had are in a CAD/CAM engineering design program. I e-mailed the plans to a buddy who did not have the program on his computer. No joy. I'm working on a power point slide that will hopefully be of some help. I should have it to you tomorrow. It's really rather simple when you see the pix. HOWEVER....I just spent 20 minutes trying to to explain the cuts and bends......Now I am fixing a drink! The pix will be easier.

Simply put the start is a 26" by 20" piece of stainless. 2" on each side are turned down leaving the 22" span. 2" aft is turned up leaving the 18" chord. Weld the original tab to the top leaving enough of a lip (<1/8") to allow the whole thing to be re-attached to the boat with the original gear. The original tabs had one side turned up and one turned down. The angle offered nothing. It looked sexy on the floor like a go fast. The back was turned up for stiffness. The newer Rays do not have this style tabs. My welder just cut the downward turn on the original tab off. He left the upward turns on for reasons unknown to me. Maybe stiffeners? Maybe he used it to hold on to when welding the two together. In any event, it does nothing positive or negative so no biggie one way or the other.

The only thing I offer is to make sure you use thick enough stainless. Melida, a member from Turkey used the same thickness as his original tabs and we had a hell of a time with vibration.

Again, Pix tomorrow.

 

[melida]

See my post and pics as David mentions #31 at http://clubsearay.com/showthread.php/40399-fuel-consumption-query.sundancer-330/page4
Best regards.
Melida

 

[larrytbull]

thanks Guys,
that info is so valuable.

Melida,

I am curious did you make them from scratch or did you weld on an extension? reason i am asking is that if you started out @ 12 gauge across whole tab, them maybe the extra pressure caused the vibration at 18 inches chord, where as dpmulvey, had layered the existing tab over the extension, efectivly increasing the thickness.
I am going to talk to machine shop to see what is less expensive to weld supports on or to use thicker sheet

I am glad I am finding this info out now, trather than using 12 gauge 304 and finding that it had exxsive vibration

 

[melida]

thanks Guys,
that info is so valuable.

Melida,

I am curious did you make them from scratch or did you weld on an extension? reason i am asking is that if you started out @ 12 gauge across whole tab, them maybe the extra pressure caused the vibration at 18 inches chord, where as dpmulvey, had layered the existing tab over the extension, efectivly increasing the thickness.
I am going to talk to machine shop to see what is less expensive to weld supports on or to use thicker sheet

I am glad I am finding this info out now, trather than using 12 gauge 304 and finding that it had exxsive vibration

Larry,

I bought new 316ss/iron sheet from iron/scrap shop, but they were almost shiney as brand new. And didn't weld to the existing tabs, don't remember just now how thick are they maybe 8mm or 10mm, 12mm.

I had vibration because I only did downward stiffenings at sides and no other. So that caused vibration and very annoying noise. Later did aft edge upward bend/stifenings and 3 diagonal welded between aft edge stifening and vertical bracket where piston is attached. Pics can tell better than me.

Here is the video before I did the fine tunings and adding stiffenings. It's a bit long, but forexplain to David/Dpmulvey what was my current situtaion with the extended tabs.



http://s998.photobucket.com/albums/af108/melida315/Video-new%20tabs-C4%20prop%20set/?action=view&current=27032010023.mp4

In minute 1 you'll hear the noise like whistle which is the kompressror(supercharger) kicks in 1500rpm which means engine temp comes to 70 celcius so I can hit the throttle for planning then it comes 85 quickly.
In minute 2:50 temp came 85 and I hit the throtle 100rpm 100rpm to 3000rpm. At 2500 rpm kompressor gives hand to turbo and cat voice "whistle" changes to lion roaring.
In minute 4,27 rpm was 3000rpm and after that you can follow the noise from tabs.
After minute 10 I raised the outdrive through +5 and noise increased.
In minute 12:20 I hit the throtle to 3500rp which is my max permitted extended cruise rpm %10lower then wot (shortly did fast cruise)
In minute 12:50 She was cruising at 3500rpm and 25-27knots. Tabs fully retracted and drive was +5. BUT she was porpoising because the aft edges of tabs touching water and lowering the bow.
In minute 13:25 I lowered the rev to 3000rpm and lowered the outdrive to +2

Hope this helps.
Best regards.
Melida

 

[dpmulvey]

Re: fuel consumption query.sundancer 330

Hello Melida. How are things in Turkey?

Glad we can get together to help another SR owner!

Larry,

PowerPoint slide as promised. Hopefully with Melida's pictures and the slide, you will get an idea of what my tabs look like. The angles are cut and sharp edges ground down, merely to avoid any cutting hazards.

You can practice on some construction paper from a craft shop to get comfortable. My welder has been in business for over 20 years and boating his whole life. I gave him the design and he ran with it.

Good luck and please feel free to contact me if you have any questions.

 

[larrytbull]

A Special thank you to DpMulvey and Melida for all thier inside info, on this.

I called Bennett again to talk to them about the extra stress on the Hydraulics and also the option of going 22 x 12 with the DF - 12 (down fins) See Below Picture. The Bennet guys said that the down fin would help with the lift and would track better. . Unfortunately they did not have the engineering skill to say what that difference was

I asked them if thier was a reason why the stock tabs were bent the way they were, the response was maybe sea ray was worried about the turbulance of the tunnel interfering with the down tab, which if you look at the originals the side closeset to the tunnell is turned up (hmmmm...)
The Guys at bennett told me thier concern on going that far out 15-18 inches with the tab, was on the stress on rough seas, of the weight of the water on the tabs, would potentially rip off the cylander which can hold about 80 lbs of weight. They offered a possible solution of attaching a lanyard from the trasom to the tab, to help take the pressure of the downward force of the weight of the water. They said that the pressure upward from the water at speed would be fine.


so right now I am on the fence do I go with the easy bolt-on replacement of existing tabs 2 TPO2212 @ approx $226 + DF-12 @ $29, or do I go for monster tabs .... need to think about this a little bit more
Thoughts ...

 

[allan1]

I have an 02 340 Dancer that had the same tab issue. I installed a set of 02 340 trim tabs that were made to fit a Diesel that Searay uses on this model.

Now I can tab and even tilt the boat to Starboard or port. The original tabs are useless. I used the same cylinders and they work great. Under way I can tab and put the bow up and down with ease.

100% cure for the factory error.