Pat, welcome to the board!

Though more accordingly this should be sent to you as a private message, will be brief. My own thoughts regarding Gates' idea and concept of pumbing colder deep oceanic water, so to lower SST's and thus diminish the "fuel" a tropical cyclone draws upon, has tremendous merit. That said, I do not believe the dynamics of forecasting, time of preparation, nor coordination and movement of assets could possibly enable such an undertaking to occur. The only theoretical way I would imagine it working, would be to have a preplanned point of attack, perhaps just off shore a particular island, or area off a specific point on land. Perhaps then, such "in-place" assets, capable of of cooling enough area surface water to a depth of at least a few meters, might temper an approaching storm to some degree or percentage.

Assuming a mean SST of perhaps 29C, even modification of ample surface area to a lowered SST of 27C( just under typical threshold temperature for formation or maintenance of an existing sytstem , all other surface and upper air conditions aside ), it would not seem to provide enough destabilization to greatly alter a particularly strong hurricane, or perhaps a fast moving moderate one. If such SST's could be further modified more significantly, than perhaps enough impact could be asserted. (MOD's feel free to kick this too a new forum or discussion board ).