National Defense Magazine reports on an ongoing search for a rescue system that can support a large number of people in the water.
“Monica Cisternelli, project manager at the Coast Guard Research and Development Center, said the equipment should weigh less than 100 pounds and have a footprint of less than 7 cubic feet. The capability will be single-use and should be deployable from most Coast Guard platforms, including the smallest aircraft in the inventory, the MH-65 Dolphin and MH-60 Seahawk.”
The report also mentions a desire to protect “…from dangers such as hypothermia.” That could make design much more difficult. In fact I doubt their is a single solution to all our needs. The requirements to save 500 from a sinking passenger ship in the Arctic are far different from the requirements to save a hundred migrants in the warm waters of the Caribbean.
Time until help arrives and effects of exposure vary dramatically.
Hopefully anyone abandoning ship in the Arctic will have an exposure suit and access to sound lifeboats, because rescue units are likely to be long delayed. If they do not abandon with reasonable protection from the environment, rescue units will never reach them in time. Nothing that will fit inside seven cubic feet is going to be effective in protecting large numbers of people from that environment.
An over loaded alien migrant boat, with far to many people aboard, at least some of them unable to swim, and no lifesaving equipment, is a very different problem. Crowding and panic amplify the danger. Help is likely to be relatively close, but the transition from boat to the relative safety of floating unmolested in the warm water until help arrives, is very different challenge.