A floating dock(pier) is a platform or ramp supported by pontoons.
It is usually joined to the shore with a gangway. The pier is usually
held in place by vertical poles referred to as pilings, which are
embedded in the seafloor or by anchored cables.
Frequently used in marinas, this type of pier maintains a fixed vertical relationship to watercraft secured to it, independent of tidal, river or lake elevation.
In some regions of the world, a floating dock is called a pontoon.