The self-tailing winch is designed to facilitate single-handed operation. A throat atop the drum automatically maintains the line under constant tension, enabling the crew member to exert more force on the winch handle.
This type of winch is indispensable for solo sailing. Now common on many boats, it offers more line-handling flexibility since it does not require a cleat.
The self-tailing winch takes up line as would a traditional winch. A metal guide then leads the line into a slot atop the drum, where ridges prevent it from slipping, performing the function of a cleat. This keeps the line under tension while sheeting in.
Line diameter and expected load will determine the choice of hydraulic winch.