Grid system

A grid system for supporting a plurality of items of equipment from a deck of a floating vessel includes a plurality of brackets welded to the deck. A support grid for supporting the plurality of items of equipment above the deck includes a plurality of interconnected substantially horizontally oriented beams. The support grid spreads the weight of each of the items of equipment over a larger area of the deck than it would be if each item was directly supported from the deck. A plurality of detachable connecting pin assemblies are provided for detachably connecting the support grid to the plurality of brackets, so that the support grid can be attached to the plurality of brackets without the need for welding to the deck after the plurality of brackets have been previously been welded to the deck. Equipment mounting brackets are operably associated with the support grid for mounting the plurality of items of equipment above the support grid with similar connecting pin assemblies.