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-   Archive through August 01, 2004 (http://www.wakeworld.com/forum/forumdisplay.php?f=184054)
-   -   Tower wobble?! (http://www.wakeworld.com/forum/showthread.php?t=181585)

crazyirish 07-27-2004 4:36 PM

We just installed a SkyJac tower on our boat last weekend. It looks pretty sweet, however it sways side to side pretty easily. It doesn't budge at all when pulling backwards, but you can literally push it from the side and it moves way more than I think it should. So, any of you engineer types have any ideas on how to stiffen it up. We are already planning on backing all the mounts with a nice layer of plywood to see if that helps. Any and all suggestions are greatly appreciated. Thanks!!!

nvsairwarrior 07-27-2004 9:35 PM

Ryan, <BR>Hopfully you'll get numerous replies but while waiting, I'm curious as to where you perceive the Flex to be most dramatic? <BR>Some of the early towers were made of relatively soft material and would actually flex most at the horizontal to vertical bend locations. If you have this phenomenon it is supportable but not very clean IMO. <BR>I recently saw a Boss tower on a Malibu VLX that was an attempt to mimick a XStar tower. Only thing is that they used only 2.00 tubing and it needed to be reinforced at the near 90 degree bend areas at the top. Didn't look pretty IMO. <BR>If the issue is at the mount area, I would think that thin sheet metal (aluminum or Stainless) (you can use a couple of layers with a little neoprene to the glass) would work better then wood. <BR> <BR>Good luck

greenpinky 07-28-2004 4:26 AM

Actually, we supported ours by bonding plywood to the inside of the walls of the deck, where the studs from the mounts had to be installed, and it really tightened things up. We used half inch plywood. Worked like a charm. But, if it's a universal tower, you're still going to get a little horizontal movement. As long as you don't get any spider cracks around the mounts, it should be fine.

jayc 07-28-2004 4:32 AM

I get some side to side wobble on my diy tower. Its mainly down to the top deck of the boat flexing as when the tower wobbles you can see the glass flexing. <BR> <BR>I have backing plates of 1/4" aluminium and over the winter I may add some extra support to tie the top deck to the hull. <BR> <BR>I wouldn't worry too much.

monstertower 07-28-2004 5:49 AM

You can push ANY tower side to side. Do that on a few other towers to get a relative comparison of how stiff your tower is. Look at the tower when a wakeboarder cuts outside the wake. Skyjac is not doing anything different than any other tower builder so I believe what your seeing is normal. <BR> <BR>(Message edited by monstertower on July 28, 2004)

nickpman 07-28-2004 9:42 AM

Our X2 tower wobbles side to side when driving, you can push it side to side as well.... only moves about an inch or so if your really trying.

crazyirish 07-28-2004 10:18 AM

Thanks for all the replies so far. I really want to thank monster tower, we got some of your racks and they are wicked awesome! We also ended up using the instructions you had on the website to install the tower more than we used the ones that came with it. They were really helpful, especially pertaining to the procedures involved in drilling holes and mouting the bases. Monster Tower just rocks.

ilovetrains 07-28-2004 10:20 AM

Monster Tower already weighed in, but my Monster Tower has almost no flex in it, just solid. I think the designs that incorporate a bow shaped tube at windsheild height with colapsable tower on top of that have more flex. <BR> <BR>Tower flex is very subjective. It seams that some flex in the tower (as opposed to the mounting points) is desirable as this puts less stress on the fiberglass. However if it is not front to back, should not affect the rider and then is like a rattle in your new car. It annoys you, but really causes no harm and should probably be left alone.

jnewcom 07-28-2004 10:31 AM

I have quite a bit of my tower from side to side also, but none to the back or front. I have a skylon swoop tower. It never did swat that much until I put the four speakers up there, and now you can really tell a difference. Could this cause any fiberglass damage to the boat?

jnewcom 07-28-2004 10:32 AM

I have quite a bit of my tower from side to side also, but none to the back or front. I have a skylon swoop tower. It never did swat that much until I put the four speakers up there, and now you can really tell a difference. Could this cause any fiberglass damage to the boat or gelcoat problems?

monstertower 07-28-2004 8:29 PM

Ryan - if your fiberglass is not flexing your in good shape, especially since the Swoop has Hiem joints which can not transfer torsional loads to your fiberglass. <BR> <BR>CLASS IN SESSION: Tower Stiffness 101 <BR> <BR>Tower stiffness comes from material, cross section, weight on the tower and naturally the tower design. <BR> <BR>Material: Stainless vs Aluminum is basically not a factor becuase the Aluminum tube is much thicker than stainless tube but each weight about the same per foot and have about the same cross sectional strenght. <BR> <BR>Cross Section: The stiffness of a tube increases exponentially with increased diamter but most towers are factory towers and have 1.75" or 1.875" outside diameter tubing. <BR> <BR>Weight: The more you put on the tower (speakers, racks, boards, lights, children, mother-in-laws, etc) the more it will sway side to side. <BR> <BR>Tower Design: The more vertical the legs are the more sway (less stiffness) it will have. The Titan I and II are the stiffest towers built, period. We move our front legs inside the rear which makes us the second stiffest. There are pluses and minues with each design. Every factory tower and most aftermarket towers have nearly vertical legs and will be less stiff, especially if you add weight to the tower. <BR> <BR>CLASS IS OVER

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