Abstract: Embodiments of racks are assembled on floating devices to secure mobile devices, foldable sunshades and foldable tents. A rack is composed of rack poles, pole holders, a hub, a cup lock, a pipe connector or a hub bottom screw. The pole holders are fixed around a floating device. The pole top ends may be inserted into the receptacles of a hub. A cup lock may cover the hub to lock the pole top ends in the receptacles. A pipe connector may connect to a hub with its top screw and connect to a mobile device holder or a pouch with its bottom end. Embodiments of foldable sunshades may be secured on the rack with elastic straps and hooks. Embodiments of foldable tents with a bottom hook-side belt of hook-and-loop may bind with a loop-side belt of hook-and-loop fixed on an inflatable raft or boat or on a low-profile hard-hull boat.