Abstract: This invention relates to a modular float, which is in the form of an integral, closed shell, hollow float that is light weight portable and easy to use. It is intended to support marine devices such as docks, rafts and the like. The modular float has two side walls, two end walls extending between the side walls, and a generally rounded lower portion and generally rectangular upper portion, both when viewed from one side. The upper portion has a number of intersecting grooves, which are designed to carry standard sized support members, which in turn carry a deck. The grooves have resilient ridges for releasably engaging the support members.