Stainless Rad a Cage Tower

[Wingnut2u]

In 2001 Supra used a stainless steel Rad a Cage tower , from what I have been told it was discountinued after 1 year due to instability after adding tower speakers and the like. I only found this out afer adding the NVS tower speakers to my 2001 SSV. My tower now sways side to side in even the most moderate of chop on the water. It is just a matter of time before it will pull away from the fiberglass.

Does anyone have any experience with this or any suggestions on how to stabilize the tower, or will I have to get a new tower all together?

Getting rid of NVS speakers is not an option, I love those things but at almost 90lbs they are extremely heavy.

[Fishmaster]

Thats a tough one. Sounds like it was a wall thickness or diameter or material issue becuase Stainless should have been fine.

You could weld gussets from the top 8-10" of the legs to the top tube of the tower which should help. Check out the gusset about 1/2 way up the rear leg on the Roswell tower at http://www.roswellwakeair.com/towers/area_51_tower.htm for an example.

[MrBlean]

[89 skier]

I agree with MrBlean. I would think that a rider would put more force on your tower than speakers moving around with choppy water.
Maybe you could modify your speaker mount to go on the side of the tower, instead of the top. That way your moment forces created by the speaker weight would be significantly reduced.

[DiyGuy]

MrBlean,

Please.... have you not missed the point again. When is the last time you saw someone boarding so hard that they were at a 90 degree angle to the side of the boat? Assuming one could do that, then yeah, jerk on the rope a few times while at 90 degrees and it's gonna wobble (side-to-side)

In most situations though, maybe 45 degrees or a little more would be more realistic. Beyond 45 degrees the inertia (side loading) starts to bleed off anyway, otherwise you could stay 90 degrees to the track indefinately. In this scneario, (at 45 degrees to the left) the load to the tower is clearly on the left rear leg, and the front right legs and distributed thru the rest of the tower, but primarily pushing on the left and pulling on the right side.

Take a rope and tie it to your trailer hitch on your car/truck or whatever. Now move 90 degrees to the side and start yanking. What do you notice? Significant side to side movement. Tires seem to move more or suspension causes more 'wiggle'.

Now, move to 45 degrees and do the same thing. Guess what. It doesn't 'wiggle' as much.

Better yet, take a piece of pipe about 10 feet long and stick it right through the roof of your car/truck and try it.. but tie a couple of bags of concrete to the top before you try this test. Would it not be even more pronounced, especially at the 90 degree mark?

That is the issue. Wobble from side to side induced at 90 degrees (perhaps) by some heavy items at the top of the tower that simply aggrevate wingnut2u's problem.

Clearly, the structure beneath or at the mounts needs to be beefed up to distribute that load thru more of an area of say 2 x 3 inches or 6 sq inches. (mouting plates) Triple the backing to 6 x 9 and the area is 54 sq inches - considerably better.

OMG - can't wait to see what this brings as a rebuttal

[miked]

wingnut2u
I think two nvs 1010s are closer to 70 lbs than 90 lbs but regardless we have a problem.my boss tower now sways from side to side with the nvs speakers attached.add 4 boards and 2 skis that really does a jig.but with boss,the feet pivot to prevent fiberglass fracture.now I am no engineer but I think the flex is not a bad thing because its taking up some of the force that the mounting feet would otherwise be flexing/cracking fiberglass.
try taking the speakers off when trailoring long distances.I made some quick release brackets that work sweet.also I know that Duane is working on some quick release brackets himself that are designed for the nvs speakers.
and i agree with you "getting rid of my nvs speakers is not an option".they sound too good.by the way have you got the "what are those things up there" yet?.I told one old codger they were heaters to keep the rider warm while riding.he said he was going to get a pair for his fishing boat to stay warm.lol.

[Fishmaster]

DiyGuy - you stirrin up the pot again?

[DiyGuy]

MonsterTower,

Not yet....


And, I go on record.. "I am NOT an engineer, but I did stay at a Holiday Inn Express"

[MrBlean]

DiyGuy - having stayed in a Holiday Inn Express you will, of course, know that the force exerted on the tower by a boarder at an angle to the boat (rather than orthogonal to it) will be relative to the sine of the angle subtended between the line and the direction of boat travel.

Given (as you say) that a 45 degree angle is realistic for a rider cutting hard, a rider in that position exerts 0.7 times the force he would at 90 degrees to the boat. Therefore, a 250lb rider at 45 degrees has the same effect as a 175 lb rider at 90 degrees. That assumes the force is only related to body weight and takes no account of board size and other variables but it's close enough for the purposes of this "discussion".

Beefing up the deck won't stop the tower flexing. As miked says, the energy has to be dissipated somewhere and if the deck isn't taking it, something else has to.

Because the tower flexes slowly as the rider progressively pulls you don't notice by how much. Moreover, unless he/she falls, the load is gradually reduced as he/she cuts back in. Again, the load is gradually reduced and the tower gradually recovers it's position, so slowly that you don't notice the degree of movement.

But, when caused through vibration exacerbated by top loading, the tower flexes and recovers quickly, at a rate proportional to its rigidity, the load and any harmonic effects resulting from the design. Moreover, because it is happening quickly, when recovering from a sideways load (or shock) it will overshoot the upright position and flex the other way hence the degree of movement will appear almost doubled. It's much easier to see this happening as it is relatively quick.

All I'm saying is that fitting the speakers has highlighted how flexible the tower is. It flexes the same amount when pulling a rider. You just don't notice it.

Hence, if you are concerned about the amount of flex caused by the speakers, you should equally be concerned about the flex caused when riding.

P.S. I have never stayed at a Holiday Inn Express. I'm an engineer and am not ashamed of it.

[DiyGuy]

MrBlean,

So, now having been set straight by engineer talk, which makes perfect sense to me, what would be your suggestion to stop the excessive side-to-side shake due to the increased weight of speakers on the tower? The concern is that spreading of existing spider cracks will, as he says, sooner or later, cause more serious damage to the gel coat and perhaps even structural failure somewhere along the way.

A new/different tower? Reinforce backing plates? Remove speakers? It seems clear wingnut2u's problem is the concern that the current shake is unacceptable?

Now, let me get my pencil ready for a proposed fix. I'm going back to a Holiday Inn Express to visit an old friend - Mr. Common Sense, to see if that will generate some new ideas.

[MrBlean]

Sorry DiyGuy, I had to go lay down for a few minutes. Did I read "makes perfect sense to me" or was that just a flight of fancy on my behalf? No, my eyes don't deceive me, it's there in black and white Congratulations, for once we agree.

The gel coat cracks can only be generated by flexing of the underlying glass. Unless you can stop the flex completely, cracking is inevitable. The flexing may be a result of the glass being too thin (to handle a tower mounting) or the fact that the design of the mount is such that it exerts excessive twisting moment. If the tower flexes, this will change the loading on the feet and the angle at which this is delivered so stopping the tower from flexing might help the problem, as will larger tower feet.

In my opinion (and that's all it is) the fact that the tower was withdrawn after 1 year provides the answer. It's not fit for purpose - or at least the purpose that many people put it to - that of adding speakers etc., which is not unreasonable of them.

Monster's suggestion of reducing the flex with some gussets both front to rear (as per the Roswell) and better still, side to side in the top corners, will reduce the flexing itself. Re-inforcing the glass under the mountings will also help but these are only band aid solutions to a problem that shouldn't really exist in the first place.

The situation sucks and personally I would try my best to resolve it with reinforcing the deck and welding some cross braces in the top corners. Other than that, it's hand deep in pocket time for a different tower. I'm sure Bill would be happy to oblige.

[NAW]

Wingnut2u, Is your tower 1 1/2" diameter tubing? I've had problems fitting accessories because Skier's Choice has always said the Rad a Cage was 1 5/8" tubing. This would cure the discrepency as a friend of mine has an '01 Launch with the small tower tubing diameter and it also sways and creeks. However, I've been in '02 and later SC products and the towers were relatively solid.

IMO, If you have the means, upgrade the tower. I would look into retro fitting the '04 Gravity Games and Launch tower to your boat. It's the one on my Launch and is unebelievably solid and quiet.

[Wakeside1]

If it were my boat with 70 pounds of tower speakers plus racks, lights, boards, etc, with excessive tower sway, I would consider replacing the tower with a Titan Series I or II. The Titan tower is without question is the stiffest tower on the market and could easily handle 70 pounds or even 100 pounds.

I just heard of a customer that mounted a Titan tower on a boat that had a tower removed and they were able to mount over the existing mounting locations hiding the holes thereby bypassing the gel coat work. Even though the Titan usually has a wider footprint, it still looked and worked fine on this particular boat. Of course on some boats you would need to gel coat all four mount locations to switch towers - it just depends on the boat and old tower.

Mike
http://www.wakeside.com

[salmon_tacos]

Just go with the gussets. Those should stiffen it right up. It's really great if the tower is just polished stainless (as on all the Supras I've seen) as you won't have to powder coat it again or anything. The material should only cost $30-60. You could cut it yourself or have it done. I can't imagine the welding would cost ALL that much since it's a pretty simple job.

[Wingnut2u]

As a band-aid solution I am getting some backing plates for reinforcement. However, I still believe that this will only minimally reduce the "jiggle".

As far as the diameter of the tower, I do believe that I remember hearing my install guy say it was 1 5/8 (maybe even smaller) compared to the 1 7/8 that Supra quoted me. Then again, what do dealers know. All they want to do is sell you a new boat. In all honesty, that was the dealers solution to my problem. Little did he realize that was the wrong answer and when it comes time for a new boat I want a dealer who is interested in service and keeping customers, not just making a sale.

Whew, got side tracked there, back to the issue at hand.

The NVS system is great, people are always asking me if those are subs up there. I'll have to remember about the heaters next time someone asks.

Thanks for all of the suggestions and keep 'em coming

Guess I better go sleep at a Holiday Inn Express so I can figure all of this stuff out.

[DiyGuy]

Wingnut2u,

Do you need a wake-up call? It's an express type.. the phone only rings a half a ring, and thats it!

Everyone has some good ideas and I think (believe it or not) MrBlean has a few good pointers. I concur backing plates would be the least expensive and easiest attempt to stabilize the shake. Beyond that, having gussets welded in would be a pain.

Further, it would really be nice if some folks that work on boats and are familiar with a lot of different ones could chime in with thier knowledge and experience on the issue. Bill (Monster Tower) could lend an objective perspective and other Supra owners would be great to hear from as well.

Short of a new Tower, try the easy stuff first. A new tower would only be the start. Then you would have 6 areas to have to deal with getting sanded down, holes filled and re sprayed with gel coat. That would suck! Hopefully, more Supra or Rad-a-Cage owners could add a few words to the topic. My belief is that the tower, being stainless is inherently strong. {Tell me when to open mouth - insert foot}

~~~~~~

[Fishmaster]

The more I've thought about this thread the more I dont think backing plates will do much. The stiffness of tubing increases exponentionally with diameter so it it is 1.5" diameter the material and thickness dont mean much and the sway will be significant no matter what you do.

If you weld a gusset then bias it to come farther down the legs than across the top section. The vertical front and rear legs are likely what is deflecting most.

With that much weight up there as well as loaded up with boards in racks, all that weight on the tower will definately cause sway. A stiffer tower would help and the Titan has the best stiffness in the market but you either love or hate the looks (I love it) - also resting the tower on the windshield is a negetive to the design. Were the next stiffest or a little stiffer by various computer stress modeling results. If your boat will fit the new factory tower and it is truly 1-7/8" that would be the best option, especially if the bases match up and you can uses your existing holes.

My $0.02

[Wingnut2u]

I thank all of you for your $0.02, unfortunately I think that I am only up to about $0.10. Sure wish more people would chime in.

I am surprised that there have not been any other Supra owners who have had similiar experiences, who knows, maybe a cat got their tongue.

Well, for those that have chime in, thank you and if anything new comes to mind, please post it.

[DiyGuy]

I think the tower is actually 1 3/4 inch. What difference would that make?

Need some new ideas..

Are there ANY Supra owners with Rad-a-Cage tower than can chime in.

[Broccoli B]

I have a moomba with the Rad-a-cage and i can sit on the top of it and it doesn't sway at all.

[SupraBoarder]

I feel overly qualified to reply to this thread.
I own a Supra Launch.
I have tower speakers.
My tower sways.
I've thought of ways to fix it.
And most importantly;
I work at a Holiday Inn Express.

So here it goes.
The powder coated tower that came on my supra launch is 1 5/8". I'll attach a picture with the new tower box from 80feetout. There's a few things that we've come up with that will most likely reduce the amount of stress that is put on your gelcoat as a result of swaying. If you look at the tower mounts from inside the boat, you should see 4 seperate washers. Get rid of those and put a solid plate on under there, then bolt it down. BUT before you do that, get some industrial carpet from lowes or even better some gator grip and cut it to fit under that new shiney plate. Also, cut another piece to fit between the actual tower mounts and the gelcoat on the outside of the boat. Reinstall everything and use self-locking nuts(haha that sounds funny). You're going to have to tighten these a few times during use just to get everything locked down for good. This will provide a cushion and a barrier between the gelcoat and the swaying tower, thus reducing the amount of rigid pressure put on the fiberglass.

Oh and just so you know, I worked all night last night and I'm just getting off work here at the holiday inn express.

[Wingnut2u]

Just FYI, apparently this issue is most common with the 1 5/8 Stainless Steel Rad a Cage tower that was installed on the 2001 model only. The Rad a Cage tower was re-designed for 2002 and beyond. I have some backing plates on the way and I will definetely consider your suggestions.

[MrBlean]