Understanding Roller Furling Systems - by Bill Fastiggi

The use of  headsail Roller Furling and reefing systems on sailboats has increased dramatically over the past fifteen years.  When they first became available, they were viewed as a novelty by most of the sailing community.  Today however, almost every cruising boat, and even many racing boats are equipped with roller furling.

There are may types of furlers available today.  Some work well, and some are more temperamental.  In order to simplify this article, I will categorize them into three different styles:  the most common "head swivel" type, the "internal halyard" type, and the "wire luff" type.

The basic set up of the "wire luff" type of furling system is a removable swivel drum at the deck that attaches behind the forestay, a headsail with a wire luff (no hanks or luff tape), and a head swivel that attaches to the top of the sail and to the halyard.  This is the oldest of the furling designs.  The most common of these types are the old Schaeffer system and small boat furlers used on racing dinghies.  The advantages of this system are low cost, ability to use other "hanked-on" headsails.  The disadvantages however, are fairly substantial; the inability to reef, the inability to furl when the halyard is fully loaded, and the huge amounts of headstay sag.

The "internal halyard" type of system goes over the existing forestay, but does not use the jib halyard.  It has an internal halyard that slides down one groove of the system, while the luff of the sail slides up the second groove.  The advantages of this style of system is typically lower cost, no head swivel - no potential halyard wrap problems, keeps halyard free for cruising spinnaker.  The disadvantages are difficult to change halyard tension for sailshape control while sailing, compression load on extrusions can make furling difficult in high load situations, and it is difficult to change sails.

The most dependable type of systems are the "head swivel" style that have a lower drum, metal extrusions, and a ball bearing head swivel.  The sail is tacked down at the furling drum fed up into the groove in the extrusion, attached to the head swivel, and the jib halyard is attached to the top of the head swivel.  This is the most popular style of system (and more expensive) and offers the best furling performance.  It also offers easier headsail changes, and some systems are equipped to remove the drum, by-pass the head swivel, and use the system as a twin groove headstay for racing with full hoist headsails.

Furling systems are great, except when they do not work correctly.  The majority of problems that can cause "furling failure" are easily preventable, and often easily correctable.

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