Abstract: A dock for supporting persons over a support surface such as a water bed has an elongated deck, a plurality of vertically adjustable post units, and a wheel attached to each post unit for transporting the dock across the support surface. The vertically adjustable post units are secured to the deck at spaced-apart locations and include a first elongated post section connected to the deck, a second elongated post section vertically movable with respect to the first elongated post section, and a base pad connected to the second elongated post section. A wheel assembly supporting a rotatable wheel is rigidly connected to the first elongated post section. The post units are adjustable to a transport position in which the base pad is off the support surface and the wheel is on the support surface. The vertically adjustable post unit is also adjustable to an operating position in which the base pad is on the support surface and the wheel is off the support surface for stabilizing the dock.