Line-throwing devices have long been an important part of maritime safety, and many different have been guns adapted to launch ropes from shore to ship or ship to ship. Usually they are inexpensive obsolete surplus of the era, but a change in law in 1918 led to a spike in demand for line-throwers in the US. As a result, a number of entrepreneurs put together line-throwing rifle kits. One of these was William Read & Sons, who bought 497 Model 1886 Winchester lever action rifles in .45-70 form the Winchester factory, specifically bored smooth and with barrels cut down the 14.5 inches. They packaged these with line launching projectiles, spools or rope, blank cartridges, and other accessories and sold them commercially. This particular model was used by both the US Coast Guard and Navy as well as private ship owners, and remained in use until after World War Two.

For a tremendous amount of information on line throwers, I highly recommend John Spangler's article "Guns to Save Lives":

https://americansocietyofarmscollectors.org/wp-content/uploads/2022/04/2015-B111-Line-Throwing-Guns.pdf