Designing surf tabs out of auto trim tabs

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Originally Posted by jstenger

I was hoping that they would just add actuators to the current Flow which would look similar to the pic below.

http://i1217.photobucket.com/albums/...1940703_1.jpeg

I don't think it would be that hard to do.

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But would it really be worth $500+ in actuators plus the switches and wiring just so you don't have to stick your hand in the water to switch sides?



It's not like any of these systems using the long throw 102 actuators are going to be fast enough to do transfer tricks. I've ridden a surfgated boat with the 102 actuators and the gates don't switch fast enough. That's why malibu had lenco make them special actuators that are the 102 "fast". And you can't get them unless yourre a malibu dealer with an RMA on a bad fast actuator. *maybe* you could get the Supra version of the heavy duty fast actuator, but who knows.

It's possible the autoflow would have a fast enough throw for transfer tricks because they use the short throw actuators and only have 1" of travel on the actuator to fully deployed...

If your going to build a system do it right and do an NSS type like this guy:
http://www.wakeworld.com/forum/showt...ht=surf+system

Best DIY System I've seen to date!!

Right.... Look how nice and square his back corners are transitioning from bottom to transom. No step.

Badazz work though.

I can't comment on the design specs of other systems, except to say there are two schools of thought here; either create lift to list the boat, or create drag to force the boat to crab. SurfGate falls in the former category, NSS and other systems, like Swell, land in the latter.

Testing on our product (which is decidedly different from anything else that has been posted thus far) has shown that unless you're going with the drag model, deploying the tab any further than 10-12 degrees just makes it act like a brake, and eliminates the lift that is needed to list the boat at speed.

Obviously this is all dependent upon the design specs and engineering for the system and what it is trying to do. But for anyone thinking they'll just bolt some trim tabs onto the transom of their boat, I think it would be a mistake to have them deploy very far. Obviously this needs to be modeled and tested in detail, and I could absolutely be wrong, but I feel pretty confident in the results.

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Originally Posted by jasonwm

I can't comment on the design specs of other systems, except to say there are two schools of thought here; either create lift to list the boat, or create drag to force the boat to crab. SurfGate falls in the former category, NSS and other systems, like Swell, land in the latter.

Testing on our product (which is decidedly different from anything else that has been posted thus far) has shown that unless you're going with the drag model, deploying the tab any further than 10-12 degrees just makes it act like a brake, and eliminates the lift that is needed to list the boat at speed.

Obviously this is all dependent upon the design specs and engineering for the system and what it is trying to do. But for anyone thinking they'll just bolt some trim tabs onto the transom of their boat, I think it would be a mistake to have them deploy very far. Obviously this needs to be modeled and tested in detail, and I could absolutely be wrong, but I feel pretty confident in the results.

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While I appreciate your explanation, I can't say that I agree completely with it. You're saying that the goals of a surf system are to list or crab. I don't really agree. The goal of a surf system is to delay the convergence of the wakes.

There are members here that have made "ghetto gates" that don't have an angle at all and essentially extend the running surface of that side of the hull, but in a straight line, not in the Malibu 22 degrees. I guess it could be argued that even with a straight ghetto gate that it's effectively making the boat crab because you're kind of placing a straight rudder on the non-surfside corner. But then we're talking semantics.



I guess the only thing that I really disagree with you on is that NSS is in a fundamentally different school of thought from the surfgate. they're not. And that's why Nautique LOST the lawsuit and is paying millions to Malibu.

I retrofitted my own manual version of an NSS onto my supra. Mine was modeled after the Nautique's in that it extended 3" OUT from the hull and only .75 to 1" DOWN. My boat sat level, just like the G23's do when they're deploying their NSS. (I've ridden a G23 and a G25 with NSS.) Likewise, my NSS most certainly affected the turning of my boat. we got used to only turning away from the surf side when it was time to come back and pick up our rider. :-)

The NSS is most certainly affecting the side of the hull, just like the Surfgate. however, there's an inverse relationship between length of the delayed convergence device and the length necessary for it to be effective. My NSS stuck up 90 degrees from the hull. At full deployment it only needed to be 3". The surfgate is 17.5" and is at a 22 degree angle. The members that have made 0 degree ghetto gates have found that they needed to be even longer than a surfgate because they had no angle of deployment.

I would imagine that my principle holds true on downward deployed devices, that the length and surface area are inversely related to the angle of deployment...

This seems to hold true in the marketplace.
Surfgate = BIG with a moderate angle
Moomba Flow = smaller with a 90 degree angle
Centurion quicksurf = big surface area with a more moderate angle
NSS = small with a 90 degree angle
Mastercraft Gen 2 = more moderate angles with big surface area
MB Sports Gen 2 = 90 degree angle with a smaller surface area beyond the hull (basically an NSS with a different method of deployment)

The Supra Swell seems to be the one that I can't quite nail down as far as the angle vs. surface area. Because it's certainly a reasonable amount of surface area, but they crank that thing all the way down as well. Yeah, it's likely acting like a brake in addition to delaying the convergence? And maybe that's having it function like a surf system and a "wedge" type device at the same time?? Not sure. Sadly it's one of the systems I didn't get to ride last year. I will try to get on one in May.

I'm by no means an expert. But I do have first hand experience with a handful of surf systems...

Agree, maybe we're getting hung up on terms but my gates are held out by a surprisingly small hinge pin. There is no way it is causing the boat to yaw (crab). Even @ speed.

Tomorrow I am picking up some aluminum blocks to make a level spot on the back of the boat. to mount the tabs to.

I think the biggest thing I am trying to get away from by adding the tabs is with my 21v I have 750lb sacs in the back compartments and I have to put a 400lb sack on the back deck. also if I have less than 4 people in the boat we put a 400lb sack on the back seat. I am having my seats re-vinyl right now and I hate putting sacs on top of the vinyl I put towels down but just do not want the extra ware and tare on the seats.

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Originally Posted by wolff supra21v

Tomorrow I am picking up some aluminum blocks to make a level spot on the back of the boat. to mount the tabs to.

I think the biggest thing I am trying to get away from by adding the tabs is with my 21v I have 750lb sacs in the back compartments and I have to put a 400lb sack on the back deck. also if I have less than 4 people in the boat we put a 400lb sack on the back seat. I am having my seats re-vinyl right now and I hate putting sacs on top of the vinyl I put towels down but just do not want the extra ware and tare on the seats.

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Just have the guys put some heavy steel plates in the seats before the new vinyl goes on. It could be your secret ballast. :D

I am already running steel tractor weights in the boat. Boat and trailer weight 5800lb on 6000lb trailer I do not think I can add any more.

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Originally Posted by wolff supra21v

I am already running steel tractor weights in the boat. Boat and trailer weight 5800lb on 6000lb trailer I do not think I can add any more.

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Glad to see that I am not the only crazy one.😄