Around 1590, hammocks were adopted for use in sailing ships; the formally adopted the sling hammock in 1597. Aboard ship, hammocks were regularly employed for sailors sleeping on the gun decks of warships, where limited space prevented the installation of permanent . Since a slung hammock moves in concert with the motion of the vessel, the occupant is not at a risk of being thrown onto the deck (which may be 5 or 6 feet below) during swells or rough seas. Likewise, a hammock provides more comfortable sleep than a bunk or a berth while at sea since the sleeper always stays well , irrespective of the motion of the vessel. Prior to the adoption of naval hammocks, sailors would often be injured or even killed as they fell off their or rolled on the on heavy seas. The sides of traditional canvas naval hammocks wrap around the sleeper like a , making an inadvertent fall virtually impossible. Many sailors in the Royal Navy, during the 1950s at least, used a spreader - a length of wood with a V cut in each end to engage the second hammock string on each side. The first string was set up more tightly than the others so that it raised a protective lip along each side to keep out drafts and prevent the sleeper being thrown out. A narrow mattress was also issued which protected the user from cold from below. In addition naval hammocks could be rolled tightly and stowed in an out of the way place or in nets along the as additional protection during battle (as was the case during the ). Many sailors became so accustomed to this way of sleeping that they brought their hammocks ashore with them on leave. The naval use of hammocks continued into the 20th century. During , troopships sometimes employed hammocks for both and in order to increase available space and troop carrying capacity. Many leisure sailors even today prefer hammocks over bunks because of better comfort in sleep while on the high seas.
Shoulder Squeeze — That nagging problem when the sides of the hammock wrap too tightly around your shoulders causing discomfort through the night.
If you don't want a rope hammock that wraps around you, select one with spreader bars that stretch the ropes so more than one person can sit on it and also prevent "cocooning."