Lectrotab Trim Tab Install - 275SD

[Judge]

I need some opinions from guys already running the Lectrotab Trim Tabs and have experience with their performance on the Yamaha's as it pertains to trim tab size.

I have read just about every Lectrotab post and most guys say the tabs are super responsive and only 1 - 3 LED's need to be lit on the controller to get the benefits desired at various speeds and sea conditions. At least one or two guys thought they would have liked to try smaller tabs or even mount them so they are a little higher from the water.

I'm installing them on a '22 275SD and originally planned to install a set of 10" Deep x 14" Wide stainless heavy duty tabs. Unfortunately the boat has underwater lights that are creating some challenges.

If I were to install the tabs against the lights, it pushes the tabs further out towards the chine and causes the actuator to get pretty flat or close to parallel with the tabs because the angle between the swim platform and transom gets pretty shallow the closer you get to the chines. This makes it more difficult to get the 1/2" above the hull bottom adjustment for the trailing edge of the tab whem the actuator is fully retracted. I also worry about the actuators pushing in more towards the transom than they try to push down against the tabs. I also run into challenges with the tie down straps and I'm also dry rack storing the boat so have to be worried about the forklift coming in to lift the hull.

If I try to move the tabs beneath the underwater lights, I can't get the 1/4" of space I need from the bottom of the hinge to the bottom of the hull. The hinge will be at or just below the bottom of the hull. The port side is closer to working but of course the guy who installed the starboard light mounted it 1/2" lower than the port light... go figure!

Mounting the 10 x 14's under the light give the actuator a much better angle and the adjustability I need for the tabs to get the trailing edge 1/2" above the bottom of the hull.

So here are my options:

Option 1 - I mount the trim tabs to a piece of plywood and then use a carbide hole saw to cut a partial circle (about 1/3 of a circle) out of the mount that is about 2" long and 1/2" deep so I can mount the tabs higher by positioning the tab mount up around the bottom of the light . I spoke with Russ at Lectrotabs and he said cutting a notch in the mount is a reasonable approach and he had to make some custom tabs for another boats to deal with underwater lighting. But cutting 1/8" stainless will be no fun.

This option allows me to use the 10 x 14 tabs I had made and mount them in a position that gives me the best adjustability for the actuator. It also eliminates issues with the tie down straps and reduces concern of damage by the forklift when moving the boat to and from the rack.


Option 2 - I ordered some 9 x 9 tabs from Amazon because I could get them in a day for comparison purposes and then return them if needed. The 9 x 9 tabs could be mounted next to the lights and still give me a decent actuator angle and adjustability when mounted under the swim platform. I would still eliminate issues with the tie down straps and reduce concern of damage by the forklift when moving the boat since they are not as wide.

The downside of this approach is that I go from 140sqin of surface area down to 81sqin of surface area. Everything I have read from most trim tab manufacturers says you want the biggest tabs you can fit.... but they also say that there is not a one size fit all approach because there are so many variables from one boat / hull type to another (including Russ at Lectrotabs who says some boats don't need them or are on the ragged edge of needing them or some boats are more responsive to tabs than others).

I also read the faster your boat can go, the smaller the tabs that are needed so boats that can cruise over 40 knots can get away with smaller tabs. However, slower moving boats need bigger tabs to have an impact.

When I spoke with Russ about the 9 x 9's he said while they don't recommend them for a 27' boat on their website, it doesn't mean they won't work and provide the benefits. He said instead of needing 2 or 3 LED's of input, I may need 3, 4 or 5 LED's with the smaller tabs. He also said he could make me a set of 9 x 9's (or 12 x 9's) in two days if I went with aluminum instead of stainless (but I prefer stainless since I run in salt water and it's a bigger boat).


One of the main reasons I'm adding the tabs is because I boat in southwest Florida in the Gulf. When the seas start getting 2 - 3' or more of chop, it will be nice to run slower but keep the bow down and stay on plane at slower speeds to deal with the rougher water.

My concern with the 9 x 9's is whether they will be too small and not provide the benefits at slower speeds in rougher water because they could be too small struggle to lift the stern enough to keep the bow down. They will also only be positioned in the center of the transom between the jet and the chine where the 10 x 14's will run from the furthest left side of the transom under the lights about 3/4 of the way to the chines (and there is clearance when the nozzles are hard-over).


On the flip side, guys who have installed everything from 9 x 16's, 9 x 12's and 10 x 14' tabs on 21 to 25 foot Yamaha's seems to agree that more than 1 - 3 LED's of input is all that is ever needed.

So after all of that background.....

Do the guys with the Lectrotabs installed think a 9 x 9 could be enough for a 27 footer or do they think I would be better off modifying the 10 x 14 tabs to make them work as originally planned?

No one on here has put trim tabs on a 27' Yamaha with a 9' beam yet or one that will weigh around 7500 - 8000lbs fully loaded so I'm going to be the first.... but there is a lot of good experience on this forum that I value.

Please let me know your thoughts when you can. I need to make a decision and get them installed in the next few days.

Thanks!

 

[zipper]

I don't know the hole pattern, but option 1 is what I first thought. And what I would have done shown by the red arc below.

 

[Judge]

So the red is actually where I would be cutting the notch.....





This is where I would be mounting the 10 x 14 tab if I cut the notch out for the light. The way I had it with my card board cut just won't work well with the actuator angle, the trailer tie downs and the forklift. This position solves all three problems with the 10 x 14's.

 

[Judge]

If I go with the 9 x 9 tabs, this is where they would be mounted. The angle for the actuator mount is decent here and not issue with the trailer tie downs or forklift.

 

[zipper]

The 9 x 9's do fit better with the light placement. The larger tabs will reduce the effect of the underwater light. I was one that installed 12 x 12's on my AR230 in 2017, rarely used more than 2 bars on the controller. The smaller tabs should work fine with a little more use of the controller versus the larger tabs. Any chance that you can return the 10 x 14's for a set of 10 x 10's?

 

[Judge]

The 9 x 9's do fit better with the light placement. The larger tabs will reduce the effect of the underwater light. I was one that installed 12 x 12's on my AR230 in 2017, rarely used more than 2 bars on the controller. The smaller tabs should work fine with a little more use of the controller versus the larger tabs.

I'm not too worried about the underwater light perfomance.... probably won't do much night boating but I do agree the 9 x 9's would be easier to install since I don't have to do any cutting and they check all the install positioning boxes.

It is encouraging that you rarely used more than 2 bars of input with the 12 x 12's.

It would stand to reason if the 12 x 12's only need about 2 bars at 144sqin, the 9 x 9's at 81 sqin might do the job at 3 - 5 bars. I'm just on the fence about how well they work at lower speeds in the bigger 275.

 

[HangOutdoors]

You don't want the hinge below the hull. The Trailing edge should be higher than 1/2" I prefer 1-1.5" if possible. Otherwise even fully retracted they will be actually causing influence due to the angle our boats are to the water while at speed. The 9" should be fine.

 

[Judge]

You don't want the hinge below the hull. The Trailing edge should be higher than 1/2" I prefer 1-1.5" if possible. Otherwise even fully retracted they will be actually causing influence due to the angle our boats are to the water while at speed. The 9" should be fine.

I would be a little concerned having the trailing edge 1.5” out of the water. The full stroke on the short actuator is only 1.5”. That means at best the tabs would only be level with the bottom of the hull at fully deplioyed.

When you say angle of our boats… do you mean the angle of the transom or the angle of attack when underway?

I watched a great video posted by one of the guys on here who mounted a camera under the swim platform to show how Thrust Vectors work at low and high speeds. I believe it was an AR240. The video showed the nozzle and closest part of the transom and ride plate along with the boat speed. At 8mph the boat was coming on plane and the transom section next to the ride plate was out of the water. It is amazing that very little of the transom is touching water at 8 - 10mph.

The part of the transom shown in the video is where the end of the 10 x 14 tabs would be mounted under my lights and would have just been showing in the video. Based on that video the tab would have been out of the water at 8 -10 mph fully retracted. At the very least the trailing edge would have been level with the water at slightjy bow up during planing. Everything I’ve tead says the tabs should have no impact if they are level with the bottom of the hull fully retracted.

I'd be concerned that 9 x 9 tabs would have enough impact on the 275 if the trailing edge was 1.5" above the bottom of the hull given it has 40% less surface area than the ones most people have installed.

 

[Judge]

I found the video.....

I did a screen shot at 8MPH and the arrow shows where the end of the 10 x 14 tab would be. If the bottom of the hinige was 1/4" above the hull line and the trailing edge was another 1/4" - 1/2" above the hull line, I would not think it would be having much impact on the boat.






After watching this video and the transom at speeds in the teens and twenty's, I don't think much of the 9 x 9 tabs would be in the water based on the location I would install them on the transom. If you look at where I drew the mounting lines below..... about 2/3 of the 9 x 9 tabs would be out past the strake. As the boat gets on plane and the further out you move from the keel, the more the transom is out of the water and the right side of the tab.

So that has me wondering how much impact they would have at certain speeds. But maybe I'm over-thinking it?

 

[HangOutdoors]

I would be a little concerned having the trailing edge 1.5” out of the water. The full stroke on the short actuator is only 1.5”. That means at best the tabs would only be level with the bottom of the hull at fully deployed.

Not sure how you surmised that. Since where the actuator is installed in the middle of the tab and the angle at which the actuator is relative to the tab based on the swim platform or transom, the throw could extend it much further or less depending on how you mount it.

I would slide them toward the pumps as much as you can without affecting steering and your bottom redline is too high in the picture. 1/4" is where I put them.

 

[Judge]

Not sure how you surmised that. Since where the actuator is installed in the middle of the tab and the angle at which the actuator is relative to the tab based on the swim platform or transom, the throw could extend it much further or less depending on how you mount it.

I would slide them toward the pumps as much as you can without affecting steering and your bottom redline is too high in the picture. 1/4" is where I put them.

On the 9 x 9 tabs the actuator mount is at the end of the tab..... and not the middle. The mounting holes are ~8" from the hinge so based on the mounting location, the actuator is only going to push the trailing edge of the tab down about 1.5" or so +/- 1/4"

My red lines are just ballpark for visualization. The bottom of the hinge would be 1/4" from the bottom of the hull at the transom.

In terms of getting them closer to the pumps..... I'm in the same boat with the 9 x 9's that I am with the 10 x 14's. The mounting plate is 2" high from the center of the hinge, I can get the mount under the far right screw and just have enough room for the 1/4" clearance to the bottom of the hull. It would be nice not to have to cut into the stainless... plus the mounting holes are much closer together on the 9 x 9's.

I prefer to get them as close to the pump as I can because it gives the actuator the best angle for adjusting the trailing edge of the tab. When talking to Russ at Lectrotab, he recommends keeping them about 2" from the chine.... but that creates issues with the tie downs straps and potentially the forklift.

 

[HangOutdoors]

Move the lights up. Patch the holes with gelcoat and finish. fairly simple and straightforward. Go all in and do it the way it should be done.

 

[Judge]

Move the lights up. Patch the holes with gelcoat and finish. fairly simple and straightforward. Go all in and do it the way it should be done.

That's more than I have time to get into. I only have access to my shop for a few more days before I move the boat to rack storage and lose the ability to do any work like this project. Plus the lights are actually in a round recession in the transom.

If I have to cut the stainless, I will..... but with the 9 x 9's I'm not sure that will be necessary. The 10 x 14's would go under the lights and all the way left for sure so I would be cutting out part of the mount to accommodate the light.

 

[Judge]

Here is the 9 x 9 and the 10 x 14 side by side for comparison.....

 

[HangOutdoors]

Oh I see. you didn't get the 9 x 9 from Russ. I am not a fan the actuator mounting position nor the non flared edges of the 9"

Personally I would go with 10 x 14 and move the light and do it that way. Your boat and you have to make the call on what you feel comfortable with and what fits in your schedule. taking them off sucks and requires much more patch work.

 

[Judge]

Oh I see. you didn't get the 9 x 9 from Russ. I am not a fan the actuator mounting position nor the non flared edges of the 9"

Personally I would go with 10 x 14 and move the light and do it that way. Your boat and you have to make the call on what you feel comfortable with and what fits in your schedule. taking them off sucks and requires much more patch work.

The 9 x 9 are stainless steel from a Lectroab Kit. The 10 x 14's with the flared edges are stainless steel and what Russ had made for me so they are both Lectrotab products.

The 9 x 9 and 12 x 9 tabs have the mount near the edge of the tab.... about ~8" from the hinge.

I can get the 10 x 14 flared tabs under the light if I cut the semi-circle in the mount and keep then hinge 1/4" from the bottom of the hull.

 

[HangOutdoors]

I can get the 10 x 14 flared tabs under the light if I cut the semi-circle in the mount and keep then hinge 1/4" from the bottom of the hull.

This sounds like a good plan.

 

[Judge]

Any chance that you can return the 10 x 14's for a set of 10 x 10's?

Sorry I forgot to answer this part of your question!

Lectrotab had the 10 x 14 tabs made by their supplier so not sure if I can return them. They don't make a 10 x 10 stainless as a standard offering. They only make a 9 x 9 and a 12 x 9 stainless.

They do make a 9 x 10 aluminum tab... as well as the 9 x 9 and 9 x 12 in aluminum as well.

As I compare the 9 x 9 and the 10 x 14, I could see the 12 x 9 being an option. A 12 x 9 gives me a little more surface area but would also allow me to mount it next to the light. One of the guys on here did go with a 9 x 12 on a 25' FSH.

Some of the reading from tab manufacturers is interesting.... at least one recommends staying with a 9" cord and then going wider based on transom space and boat size. They recommend going to a 12" cord when transom space is limited.... which is somewhat the case with these transoms.

 

[Judge]

Looks like I'm firing up the whole saw to cut some stainless this afternoon.......

I have to say Russ at Lectrotab is very helpful. I sent him a few pictures of the placement of the 9 x 9's vs 10 x 14's and asked for his recommendation. While he said they don't recommend the 9 x 9's for a 27 footer he isn't against them and he gave me some quantifiable data. He said it has become evident that the Yamaha jet boats don't require a lot of tab to get an improvement so the 9 x 9's could work but require more input from the actuator.

For a 27-28’ boat, at cruising speeds as follows, with tab size recommended at that speed:

26-29 MPH – 12x18” (216 sq/in.)

32-36 MPH – 12x12” (144 sq/in.)

38-40 MPH – 12x9” (108 sq/in.)


Russ also said they like to set the worst case limit to 800 lbs. of force or less at full deployment (the actuators can push up to 1,000 lbs.), this allows some cushion for the high end and the pressure will only get less as the tabs come up.

Here’s a breakdown of the force on these tabs, at the speed ranges of 26 – 40 MPH

Size. 26 MPH 40 MPH

9x9: 164 lbs. 389 lbs.

12x9: 292 lbs. 692 lbs.

10x14: 315 lbs. 748 lbs.

12x12: 390 lbs. 923 lbs.

12x18: 585 lbs. 1385 lbs.


The above data is interesting as too much tab can potentially be too much for the actuators to handle at faster speeds if the tabs are fully deployed.

So after feedback here and getting data from Lectrotab, I think the 10 x 14's are still the way to go.... especially if you want the tabs to perform well at lower speeds. One of the big benefits to me is being able to stay on plane at lower speeds in choppy water. Based on the above data the 10 x 14's are going to provide twice the force at lower speeds compared to the 9 x 9 tabs.

So with that... I'm heading out to the shop to do some cutting. They could make me a set of 12 x 9 aluminum tabs quickly and I could install them next to the light....... but at this point I think I would rather stick with the stainless 10 x 14's that I have and modify them to fit under the lights. I'll report back later with some pictures once I cut the notches.

 

[Judge]

There's no turning back now!

The carbide hole saw I bought worked like a champ! It cut perfect semi-circles in the mount so I can get the tabs under the lights. It worked better than going to a machine shop.

My brother-in-law came over to give me a hand so I could get one screw in each tab so I could position both of them and drill all the pilot holes.

Now I'm headed back out to the shop to finish drilling and countersinking the holes tonight. Then I will remove the tape, wipe down the gelcoat and score it a bit. Then tomorrow I'll get the 5200 out and get it into the holes and the back of the mounts.

I will say that I'm surprised how thin these transoms are. When I cut the hole in the bottom of the swim platform for the transducer, I measure it to be about 1/2" thick. The transom itself is the same thickness.

I do recommend getting a 5mm drill bit for the #14 screws. The instructions say 3/16 or 5mm. I bought a couple good 5mm bit since they are a shade bigger in diameter at .196 inches. Even with the 5mm drill and the #14 screws being .25 inches the screws are tight going in. They would have really been tight using a 3/16 bit.