To one of these rings was attached the grip itself, an iron claw, to the other numerous ropes, which drew it by machine power after it had been thrown by a catapult and had seized the enemy's ships.
By means of this line a hawser was drawn out from the shore to the ship, and along it was run a cradle in which the shipwrecked persons were landed.
[citation needed] In 1808, Henry Trengrouse designed a rocket-based system which was similar to Manby's in the use of the line and hawser, but instead of a mortar he suggested a rocket, and a chair was used instead of a cradle.
[11] The advantages were that the rocket was much lighter and more portable than the mortar; that the cost was much smaller; that there was little risk of the line breaking, because the velocity of a rocket increases gradually, whereas that of a shot fired from a mortar was so great and sudden that the line was frequently broken; the whole of Trengrouse's apparatus could, moreover, be packed in a chest four feet three inches by one foot six inches, and carried by vessels of every size, while Manby contemplated the use of the mortar only on shore, and the safety of the vessel depended therefore on the presence of an apparatus in the vicinity of the wreck.
[12] In 1877, David A. Lyle, a first lieutenant in the United States Army, was engaged by Sumner Increase Kimball, the only superintendent of the U.S. Life-Saving Service, and developed 3 bronze, smooth-bore guns of different sizes to be used as line throwers.