This invention relates to a mooring structure and method of construction thereof, comprising a triangular template or diaphragm having vertical sleeves at the corners through which tubular legs or piles are driven in telescoping arrangement while the template is supported by beams whose ends are held on two barges straddling the structure. The sleeves are welded to the legs. A prefabricated triangular tripod is welded to the top of the legs. Concrete is then poured into the legs. One or more diaphragms may be used with each structure at a selected height above or below the water level.