obtained by directing a controlled column of frigid ambient air vertically downward against the surface to be frozen the air temperature should be at least below about minus one degree c in order to effect freezing of sea water as mentioned in the use of spraying techniques the spraying operation in addition to providing for the formation of ice particles by the freezing of water drops results in the formation of a slush ice which is of a salinity greater than the normal salinity of sea water the slush ice is in effect a residue having a salinity somewhat higher than that of the sea water initially frozen from the droplet spray as noted the refreezing of this slush ice is responsible for the development of strength in the formation spray formed ice structures in the case of spay ice construction it is this refreezing which adds to the time of construction and which is needed in order to develop the desired strength of the load bearing ice structure by the present invention an initial ice structure is formed for the purposes of this invention the initial ice structure is that initially formed at the start of the construction and which in effect forms the base upon which the final ice structure is constructed overall the process is cyclical involving spraying freezing and refreezing and spraying etc a cycle that is repeated until the structure is completed by the present invention the freezing and refreezing portion of the cycle is shortened and.