With VLR pilots spending so much time on missions over the vast expanse of the Pacific Ocean, every effort was made to reduce the amount of time a pilot spent in the water or on the water. Naval resources were stationed along the route to pluck pilots out of the Pacific. Submarines were stationed off of the coast of Japan to pick up pilots who were successful in reaching the Pacific before having to bail out or to ditch. Destroyers were stationed along the route, and PBY Catalinas were in the air.
The United States Army Air Force aircraft were also involved in air-sea rescues of their own pilots. Boeing B-17 Flying Fortresses (SB-17s) were modified to carry a motorized 27 foot A-1 Higgins boat to be dropped to downed pilots. North American P-51D Mustangs were also involved in these efforts.
15th Fighter Group members Major James B. Tapp and Captain Vic Mollan combined to develop a droppable rescue kit packaged into a 110 gallon metal drop tank while on Oahu. The picture below shows a life raft rescue kit installed on 15th Fighter Group commander Colonel James O. Beckwith’s P-51D Mustang 15 Squirt.

The kit was contained within a zipper type kapok bag as shown in the photo below and consisted of a A-3 life raft, a Gibson Girl radio, a Naval kit of visual signal equipment, and rations.

When the tank was released, it would separate and a static line would open a parachute that allowed the kit to descend slowly to the pilot in water. The life raft rescue kit was first tested by Major Tapp on December 11, 1944 as shown in the photo below.

On December 12, 1944, Major Tapp tested the kit again, this time with 2nd Lt. Charles C. Heil, the 78th Fighter Squadron’s resident swimming champion, in the water off Oahu. The concept and equipment worked so well that the Hickman Air Depot began assembling these kits.
During actual operations on Iwo Jima, the P-51D Mustangs carrying the life raft rescue kits were code named “Josephines”. In the picture below, three 462nd Fighter Squadron Mustangs are flying combat air patrol around Iwo Jima. The P-51D Mustang in the foreground of the photo, 628, is carrying a life raft rescue kits under its left wing and is being flown by Lt. Edward Linfante. The middle Mustang is 602 Metalball and is being flown by Lt. Edward Bahlhorn. The Mustang in the background is believed to be 603 Little Joe and most likely being flown by Lt. Jesse Sabin.

References:
1. The Long Campaign: The History of the 15th Fighter Group in World War II, John W. Lambert, Schaffer Publishing Ltd. (2006).