reduce potential ice loads below this level much higher loads would be resisted once the island is frozen to bottom by means of heat extraction devices brine drainage holes may be drilled vertically in and spaced over ice island 10 to provide a stronger less saline ice island they are preferably drilled through the entire ice thickness to the sea bottom and preserved by perforated pipe the drainage holes function like water wells i e brine seeps into the hole and is then pumped or bailed out as it collects therein reinforcing material may be added during the ice forming process to enhance the integrity and strength of the ice around the side and other areas where high shock loads are expected as for example sand wood fiber sawdust etc such material may be fixed with the water and pumped to form the reinforced ice or such materials may be applied separately by spreading the material over the ice already formed and then covering it with additional water certain other reinforcing materials as for example boards ropes reinforcing rods fabrics etc are applied separately the special defensive measures such as slotting heat pipes air connection piles and also explosives melting etc reduce and resist the nominal pressure due to movement of the surrounding ice sheet when explosives are used they may be imbedded around the periphery of ice island 10 such that they can be set up in an emergency e g when ice island 10 starts to move to relieve ice pressure temporarily melting may be employed by pumping warm water and distributing it along slot 16 to prevent.