US Coast Guard search operations for persons in the water (PIW's) utilize software from a program called SAROP's which takes in historical water current patterns, on scene weather/winds/currents, time of day/illumination level, size of person, what the person is wearing, whether or not the person has a flotation device and the type of aircraft or vessel doing the search. Once on scene a Coast Guard asset can deploy a data marker Bouy which can then be relocated its drift can then be used to better create a search pattern. The amount of time the Coast Guard will search for a PIW depends on the water temperature and what the PIW is wearing. A PIW with a flotation device in the Caribbean might survive a couple of days while a PIW near Alaska with no survival gear will be hypothermic in under an hour. The success of these searches largely depends the accuracy of the time/location of where the person fell off the vessel/washed out to sea. If the original information isn't very accurate then the search plan will be an educated guess. In most cases the Coast Guard doesn't search for bodies. A search action plan will be executed through such a time as it would be reasonable to expect the PIW to still be alive. Also of note a person with a 406 emergency positioning radio beacon (Epirb) will be found very quickly also a person with a strobe light at night or a mirror during the day is very easy to locate if we are in the general vicinity!