Products from Seasucker LLC employ a vacuum cup activated by hand pumping a small piston that draws a vacuum and holds the item on a vertical surface. The manufacturers claim they will stick to varnished teak, fiberglass, plastic panels, glass, stainless steel, tile, and even aluminum masts. This is true, but the issue I found was unfortunately not for very long. Having been supplier with one of their smaller plastic boxes I found that the vacuum leaked on some materials almost immediately and the box did not stay on anything for longer than 24 hours. The vacuum can be restored by pumping the piston, but this seemed to defeat the object of the product.
The small box I tried had Internal measurements: 7 7/8” inches wide x 4 7/8” deep x 3 1/2” high, (134 cu in volume). The manufacturers claim a maximum weight carrying of 40 lbs that under the circumstances I did not test to that limit. The heaviest items I could find to fit in it were two bricks weighing 8 lbs each. These held until the vacuum leaked and there was a big crash.
The box is waterproof, having been submerged in my boats bathtub for a day. However, the see-through case is not a “safe” because it has no lock
The box can of course accommodate a multitude of small items, like cell phones, keys and money and being waterproof might make a good panic box for small valuable items like watches, jewelry or money.
The box is available without the vacuum cup for $22.00. The vacuum device is also available on its own for $48.00 to attach anything to it that cannot be easily screwed to a substrate such as glass.
The Seasucker company also have a multitude of other interesting items for boats, mostly employing their vacuum system. www.seasucker.com