Sinking is usually unplanned  ... even in the EU [actual emergency radio call transcript below]


"Mayday, mayday, mayday"


"Zis iz zee German coast guard Vhat iz your emergency"


"We are sinking"


"Vhat are you sinking about?"






Bottom line is you probably stand a better chance of survival if you don't fall into the cold water in the first place.  ie don't sink to start with.