Oops, I mean a winch. My first R/C sailboat had a Futaba S10 drum winch for a sail control and that fact began a search for a simple and dependable line setup to use with the drum. Main winch line tension control is the number one problem encountered by boat builders trying to use a drum winch. After experimenting with a dozen or so setups, I have found two methods that give excellent results and can be installed in almost any boat, using any proportional drum winch. The first setup is based on a continuous, constant tension loop with the winch and idler pulley both mounted to the servo tray, which also carries the steering servo, batteries and receiver. The tray can be made of plywood or folded light gauge aluminum. This setup has the winch mounted on slotted holes at one end of the tray that lets the main loop line slack be taken up after tying up the loop. In this system the attachment points for the sheet lines are on opposite sides of the main loop, with the sheet lines exiting the hull through fairleads in the deck under the main and jib booms.
The distance between the drum and idler pulley is determined by the travel distance of you winch. This tray is best suited for larger boats such as the Star-45s, 50/800s and EC12Ms.
The second drum winch system that I will describe came in the building manual of my Jon Elmaleh Archer - my 50/800. This system is a single line, constant tension setup. In this method, single line that is wrapped around the drum, passes out of the hull over a pulley at the stern of the boat. Going forward toward the bow with the line attached to a rubber band, which is tied off to the front of the boat, usually to the jib rack. The rubber band is under tension when the winch line is at full out, with tension growing as line is pulled toward the winch. The main and jib sheet lines are also tied in at the winch line to the rubber band connection. The sheet lines each require a single block for them to pass through before attaching to their respective booms. In this system the distance between the main sheet block and the rear exit the travel distance of your winch determines pulley.