Atlantic towers, how much flex is OK?

[nuru05]

So we recently installed our Atlantic towers arch on a moody 425. We have the davit extenders (to get around our hydrovane) and 1,000 watts (5 panels) of solar on it. They did the entire design and sent it out. I installed it and it looks good and feels relatively stable, but if you grab it and try and make it sway side to side you’re able to get it to flex enough that the feet flex a tiny bit. Should I be concerned about this?

[SailingHarmonie]

Most of these arches I have seen that were installed by owners are not set up properly. It is very important for the stability of the structure to "preload" it. Although mentioned in the instructions, I don't think they emphasize it enough.

To properly preload it, you assemble it wider than the final spacing of the legs, and then pull them together with a spanish windlass, or come-along to the final spacing. Just like pre-tensioning your shrouds keeps your mast from waving around, tension in the structure stiffens it a lot.

It would concern me if the feet move relative to the deck. Even more concerned if the deck is moving. That will fatige the fiberglass, and cause leaks. That strikes me more of a problem with the mounting rather than any flexibility of the structure. Is this on a cored deck? How was the core prepared? Did you use something bigger than the little disks they supplied as your backing plates?

[nuru05]

I did preload it just as instructed during the instal and I installed them on a non cored deck with a large metal plate that was already attached to my deck from the old arch

[GreenWave]

There should be no flexing of the deck or lateral sway. Somethng is off. What kind of backing plate did you use?

[sailorboy1]

I would be asking Atlantic Towers the questions and getting the answer in writing!