Nauticus Smart Tabs

[HangOutdoors]

I don't really understand how it would be faster in a chop. You may be referring to the fact that you are able to go faster than you normally would in the same conditions, but you won't gain any top end speed. Anything that puts more of the boat in the water creates more drag will have an effect on speed. I have seen and used a boat with the Smart Tabs. They do mitigate some of the proposing and are pretty ingenious. With that said, I much prefer and recommend actual Electronic Trim Tabs that you have control over independently and at all speeds and that you can operate quickly and effectively depending on the water conditions. Also the ability to control listing when you have an uneven load on the boat is fantastic and Electronic Trim Tabs give you that. IMHO, if you are going to drill the boat, do it once and put on electronic trim tabs. Saving a few hundred or so bucks and getting less of a potential and drilling the boat and understanding that you will most likely never take them off, seems like a half step. Furthermore, you can get custom cut sizes that suit your boating needs and various water types you will be on.

The Nauticus tabs are fantastic on smaller boats or if that is all you are looking for if you don't have trim. See them and smaller fishing boats, dinghy's etc.

 

[tdonoughue]

I don't really understand how it would be faster in a chop. You may be referring to the fact that you are able to go faster than you normally would in the same conditions, but you won't gain any top end speed. Anything that puts more of the boat in the water creates more drag will have an effect on speed. I have seen and used a boat with the Smart Tabs. They do mitigate some of the proposing and are pretty ingenious. With that said, I much prefer and recommend actual Electronic Trim Tabs that you have control over independently and at all speeds and that you can operate quickly and effectively depending on the water conditions. Also the ability to control listing when you have an uneven load on the boat is fantastic and Electronic Trim Tabs give you that. IMHO, if you are going to drill the boat, do it once and put on electronic trim tabs. Saving a few hundred or so bucks and getting less of a potential and drilling the boat and understanding that you will most likely never take them off, seems like a half step. Furthermore, you can get custom cut sizes that suit your boating needs and various water types you will be on.

It's my understanding the increase in top speed comes from the altering of the angle of the jet our the back of the boat. For illustration, if you are boating with a 10 deg rise on the bow on plane, a portion of the thrust vector is pushing down, not forward. If you use tabs to adjust that to a 0 deg rise, then (presuming that the jet is aligned with the boat) you are getting all of the thrust forward and can increase your top speed.

Now, that said, as you note, you will have drag from the tabs and potentially more hull in the water increasing drag. Those are nominal, generally (if the tabs are correctly installed). And, if you do the trig on the thrust differential in the two scenarios, we are not talking about a huge increase (17% with the 10 deg, I believe--but 10 might be a lot and very rare you can actually hit 0 exactly...). But not unexpected for folks to get a few mph out of tabs. Happens with props too, but more often they have trim to optimize that thrust vector.

 

[HangOutdoors]

It's my understanding the increase in top speed comes from the altering of the angle of the jet our the back of the boat. For illustration, if you are boating with a 10 deg rise on the bow on plane, a portion of the thrust vector is pushing down, not forward. If you use tabs to adjust that to a 0 deg rise, then (presuming that the jet is aligned with the boat) you are getting all of the thrust forward and can increase your top speed.

Now, that said, as you note, you will have drag from the tabs and potentially more hull in the water increasing drag. Those are nominal, generally (if the tabs are correctly installed). And, if you do the trig on the thrust differential in the two scenarios, we are not talking about a huge increase (17% with the 10 deg, I believe--but 10 might be a lot and very rare you can actually hit 0 exactly...). But not unexpected for folks to get a few mph out of tabs. Happens with props too, but more often they have trim to optimize that thrust vector.

Haven't been on a jet boat yet that tabs have increased top MPH, and I have been on alot. Also that is why it is crucial that now when I help install the tabs I makes sure the can retract even further than the recommendation if possible. Otherwise, even fully retracted they are assisting because of the angle of our boats at WOT. Hard to get them high enough, especially on 21' boats to not add a little something. Always stay the same or lose a couple/few. The drag on our hulls evens it out. I have seen proper trim on prop boats do that. Or course depending on the condition of the hull, weather clean, waxed (reduces a bit), water temp etc. It may alter the decrease.

So with a gyroscope/leveling app on my phone even if I get a few degrees of trim - in calm low chop for testing., the MPH drops a bit. The more boat hits the water, the drag and decrease in MPH. Tested it this way a many boats. I think I have done 11 or 12 installs now with people on Yamaha's. 19'/21'/25', maybe 12 including mine. The results are the same and consistent. Haven't done a 22' yet. Wondering if maybe the redesigned hull would have different result.

On tests on chop the decrease, can be more substantial. But of course much smoother.

 

[tdonoughue]

I appreciate your experience. I can't point to having seen a top speed increase myself (too many variables--wind speed & direction, current, engine factors, boat weight (and position of the weight), etc.). That said, I don't doubt that it can happen. At the same time, there are certainly additional drag factors, and I don't think any possible increase would be substantial. So overall drops of a few are very credible to me as well.

Do you have any info on the relationship between the deck angle and the jet thrust angle? I don't know that I have seen any data on that... and that would affect things as well. I have seen some of the non-Yammy older jets and they seem to be pitched downward a bit.

 

[HangOutdoors]

I appreciate your experience. I can't point to having seen a top speed increase myself (too many variables--wind speed & direction, current, engine factors, boat weight (and position of the weight), etc.). That said, I don't doubt that it can happen. At the same time, there are certainly additional drag factors, and I don't think any possible increase would be substantial. So overall drops of a few are very credible to me as well.

Do you have any info on the relationship between the deck angle and the jet thrust angle? I don't know that I have seen any data on that... and that would affect things as well. I have seen some of the non-Yammy older jets and they seem to be pitched downward a bit.

I don't have a chart, and in retrospect I should have created one. I have been doing the installs gratis and just helping people out. I will try and remember to keep one if I am on different boats moving forward for data points and refrence.

 

[2kwik4u]

@HangOutdoors

My Rinker didn't lose any speed with the tabs deployed. They allowed higher outdrive trim angles without porpoising and that overcame the additional drag from the wetted surface.

Speaking of wetted surface area. That's really more of an issue with displacement hulls where there is laminar flow along the length. Once you transition to turbulent flow that occurs with planing hulls, frontal area become a larger driver of drag than wetted surface area. So, in theory, it's possible that if you can reduce the frontal area by increased wetted surface area, you could see less drag overall and subsequently higher speed. My slightly educated guess is that is at play in both of our experience where we see the same or just slightly lower top speeds.

 

[Judge]

Haven't been on a jet boat yet that tabs have increased top MPH, and I have been on alot. Also that is why it is crucial that now when I help install the tabs I makes sure the can retract even further than the recommendation if possible.

@HangOutdoors I'm going to be installing Lectrotabs on my '22 275SD in the next week or so with the Auto Controller. It sounds like you may be the grandfather of trim tabs on the Yamahas! So I have a question about your statement above.



When you say it is crucial to make sure the tabs retract further than recommended if possible....

1) Do you mean try to mount the tabs higher than the 1/4" recommended from the hull button?

OR

2) Do you mean position the actuator so "full retract" puts the end of the tabs higher than the recommended 1/2" from the hull button during full retract (tabs mounted 1/4" above hull bottom plus another 1/4" higher at edge of tab)?


I'm installing the short actuators with the 1.5" stroke and will be mounting them to the underside of the swim platform. Given the angle from the tabs to the swim platform, it would seem moving the actuator further back away from the transom will be limited in terms of how high it can keep the edge of the tabs out of the water.

It would seem the best bet would be to mount the tabs a little higher than 1/4" from the bottom of the hull. Maybe go up 1/2" if the location on the transom will allow?

Please let me know your thoughts... before I start drilling!

 

[HangOutdoors]

Ok, so since when we are at running, especially at WOT there is still some trim being applied because of the angle of our boats to the water. So I try and increase this fully retracted so it is higher. You will never use full down on the trim tabs. Maybe 3rd position or so, most times just 1 click, depending on how you are loaded. Never full or you will bury the bow easily and you will be shooting water up everywhere. With that in mind Increase the Angle tab up more if you can. If I had to do mine again I would of slide them more toward the Jet pumps, making sure there was enough clearance for my CJS fines. I put mine wide out since I did them before I figured out the whole tranducer placement so I wanted to be sure. The challenge comes in if you have underwater lights which may hinder placement. I also did the 10 x 14 on the next one I may shorten the width a bit. On my AR210 I modded the square holes in the tab so I could raise it up higher by making them bigger and then a small custom shim. Please understand that was my first attempt a couple years ago. Now I slide them down a bit more to the pumps and make sure I can raise them up. Much higher and the rear. an inch or so is the best. The 25' boats are easier since there is more clearance.

The challenge is if you raise them up higher on the transom, the hinge, and you are mounting to the swim platform, depending on how you mount then you get a down angle full retracted which is not preferable. Also I got slimmer mounts to help in my situation since there were a bit wide. The key is optimally you want them completely off (providing no trim) when fully retracted. That is what you shoot for, getting there may be a bit of work, or may not be able depending. Of course the diagram above is how mine where originally mounted and they work great, but I do know that fully retracted they still have influence and it knocked a couple few mph off my top end.

THIS

2) Do you mean position the actuator so "full retract" puts the end of the tabs higher than the recommended 1/2" from the hull button during full retract (tabs mounted 1/4" above hull bottom plus another 1/4" higher at edge of tab)?

Do not over stress yourself. Worst case you knock a couple/few MPH, by following the exact diagram above. If you can get the back up a bit higher that is great, but not mandatory.

NOTE: You can test fit them by using taping off the area where you will be mounting them with blue tape (always tape and drill through the blue painters tape on the gelcoat, never drill the gel coat directly). Then use some hot glue from a glue gun, glue them to the tape. Mount your actuator to the tab then you can swing it up, put a small jack or 2x4 under the tab to hold it up and then you can see where the actuator will hit the swim platform and mess around with it. Then you hot glue the actuator to blue tape on the underside of the platform on blue tape. Now you can check angles and run your level from the bottom of the boat and check it out. Once you are happy with everything. I outline the painters tape and start drilling holes in the transom at this time with it still hot glued to the transom and platform. I then break everything free, countersink all holes, but just a touch with either a 5/8" or 3/4" countersink in reverese ONLY. I clean the area with Acetone, use Marine Adhesive, 5200/4200, I either use black or white depending on color of boat. I screw the center hole first in the transom and then work my way out. THEN I swing the actuator up tight fully retracted and then start drilling holes for the bracket and wire.

 

[Judge]

Ok, so since when we are at running, especially at WOT there is still some trim being applied because of the angle of our boats to the water. So I try and increase this fully retracted so it is higher. You will never use full down on the trim tabs. Maybe 3rd position or so, most times just 1 click, depending on how you are loaded. Never full or you will bury the bow easily and you will be shooting water up everywhere. With that in mind Increase the Angle tab up more if you can. If I had to do mine again I would of slide them more toward the Jet pumps, making sure there was enough clearance for my CJS fines. I put mine wide out since I did them before I figured out the whole tranducer placement so I wanted to be sure. The challenge comes in if you have underwater lights which may hinder placement. I also did the 10 x 14 on the next one I may shorten the width a bit. On my AR210 I modded the square holes in the tab so I could raise it up higher by making them bigger and then a small custom shim. Please understand that was my first attempt a couple years ago. Now I slide them down a bit more to the pumps and make sure I can raise them up. Much higher and the rear. an inch or so is the best. The 25' boats are easier since there is more clearance.

The challenge is if you raise them up higher on the transom, the hinge, and you are mounting to the swim platform, depending on how you mount then you get a down angle full retracted which is not preferable. Also I got slimmer mounts to help in my situation since there were a bit wide. The key is optimally you want them completely off (providing no trim) when fully retracted. That is what you shoot for, getting there may be a bit of work. Of course the diagram above is how mine where originally mounted and they work great, but I do know that fully retracted they still have influence and it knocked a couple few mph off my top end.

THIS

2) Do you mean position the actuator so "full retract" puts the end of the tabs higher than the recommended 1/2" from the hull button during full retract (tabs mounted 1/4" above hull bottom plus another 1/4" higher at edge of tab)?

Do not over stress yourself. Worst case you knock a couple/few MPH, by following the exact diagram above. If you can get the back up a bit higher that is great, but not mandatory.


View attachment 208400

Thanks for your advice based on your experience!

I'm fairly sure with even the bigger 27' boat I will have to go off the swim platform.... so that will limit how high I can get the tabs at full retract. If I can get the actuators to work off the transom, that would be the easiest way to go but I doubt the short actuators will be short enough.

Lectrotabs is making me the 10 x 14 since it has the mount for the tab 5" off the hinge. Russ at Lectrotab thought that would be best as the other tabs have the mount further back.

I'm limited how close I can get them to the pumps because I also have CobraJet Steering and stock underwater lights low on the transom. Russ originally wanted me to go with the 9 x 16 tabs but they were going to be too long with the underwater lights. At least the 10 x 14 are shorter from the transom so getting them higher may be easier.

I just sent Russ a message asking him to include a set of the Low Profile Mounts to give me some options as I work on the setup. The Lower Profile Mount might help me raise the tabs a bit more mounted to the swim platform.

I also read in the Auto Controller Manual that there is a Gain setting from 1 to 3 where the tabs respond slowest at 1 and fastest on 3. I will probably set the Gain to 1 so the tabs don't move to aggressively.

I will start a thread once I get the installation started to post my progress and installation. I am going to install the Auto Controller on the dash this week while I wait for the tabs to come in. I already have the actuators so I can use my cardboard mock up with the actuators to start to plan mounting everything.

Thanks again!

 

[HangOutdoors]

Thanks for your advice based on your experience!

I'm fairly sure with even the bigger 27' boat I will have to go off the swim platform.... so that will limit how high I can get the tabs at full retract. If I can get the actuators to work off the transom, that would be the easiest way to go but I doubt the short actuators will be short enough.

Lectrotabs is making me the 10 x 14 since it has the mount for the tab 5" off the hinge. Russ at Lectrotab thought that would be best as the other tabs have the mount further back.

I'm limited how close I can get them to the pumps because I also have CobraJet Steering and stock underwater lights low on the transom. Russ originally wanted me to go with the 9 x 16 tabs but they were going to be too long with the underwater lights. At least the 10 x 14 are shorter from the transom so getting them higher may be easier.

I just sent Russ a message asking him to include a set of the Low Profile Mounts to give me some options as I work on the setup. The Lower Profile Mount might help me raise the tabs a bit more mounted to the swim platform.

I also read in the Auto Controller Manual that there is a Gain setting from 1 to 3 where the tabs respond slowest at 1 and fastest on 3. I will probably set the Gain to 1 so the tabs don't move to aggressively.

I will start a thread once I get the installation started to post my progress and installation. I am going to install the Auto Controller on the dash this week while I wait for the tabs to come in. I already have the actuators so I can use my cardboard mock up with the actuators to start to plan mounting everything.

Thanks again!

Yes you will have to mount to swim platform. A neat trick that I have done a couple of times is the I make the square holes where the carriage bolts go through in tab more of a rectangle which allows me to slightly rotate the actuator to the side which enables me to raise up the tab another 1/2" or more in a tight install.