If you have a rifle grenade, all things are possible
As illustrated in this Signal Corps image, a pair of servicemen of the 7th Air Force wrapped the line around a cricket bat-esque float, then stuffed it on the end of an M1 rifle grenade launcher device attached to an M1906. Launched by a special .30-06 cartridge, the M1 could kick out an M9A1 grenade at 165 feet per second.
The reason these Army Air Force personnel “somewhere in the Pacific” in 1944 hit on the idea to use a wooden float, some line, and a 1903 Springfield? To carry a hook offshore to help augment their diet.