How a Stuff Luff Jib Works

by Ali Meller and updates by Craig Thompson

Most current North American 505s do not have a conventional forestay and jib halyard system, but rather use a stuff luff system. The stuff luff consists of a conventional forestay, however instead of being adjusted through the mast, it is dead-ended at the mast using a t-ball fitting. The forestay is attached to a piece of flexible wire or high-tech line, which turns around a block at the tack, and runs back into the boat to a mechanical advantage and a cleat. This allows the forestay length to be adjusted while racing. The forestay takes all the rig load as there is no luff wire permanently in the jib.

Rather than hoisting a jib-with-luff-wire using a halyard as you would on a 420 or 470, the forestay is disconnected from the boat at the bow and is stuffed into the luff (hence the name) of the jib. A very light halyard - which performs the function of a jib cunningham, is used to pull the jib up the forestay, while someone pulls the forestay through the jib luff with a light line. When the sail has been hoisted all the way up on the forestay, and the bottom of the forestay has cleared the bottom of the jib, the forestay is re-attached to the tack or to the flexible forestay extension, the rig is tensioned, the jib is tacked to the boat, and the very light halyard - the jib cloth tensioner is tensioned to give the cloth the correct tension.

Alternately, the use of a zipper-luff jib eliminates the need to disconnect the forestay which has lead to widespread adoption. With the zipper-luff, you simply zip the sail around the headstay as you hoist the sail using the jib cloth tensioner.

The stuff luff system reduces the compression on the mast, as rather than turning a loaded halyard around a jib halyard sheeve (almost doubling the compression load on the mast), the forestay is fixed to the mast. It also provides a jib cunningham adjustment.

A stuff luff is normally incompatible with a jib furler, though it is possible to rig a system that has both.

With a standard jib (non-zipper luff), the sail cannot be lowered without disconnecting the forestay at the tack. Since you would not disconnect the tack while sailing, you cannot lower the jib while on the water. An alternative to lowering the jib is to disconnect the jib sheets, wrap the jib by hand around the forestay, and reconnect the jib sheets.

Another alternate to the zipper or conventional luff is to have your sailmaker to make your jib with tabs rather than a full luff tape, you will be able to lower the jib on the forestay, and leave it lying on the foredeck - as with the standard jib, you will not be able to remove it from the forestay without disconnecting the forestay. If the tabs have snaps or velcro - making them work like jib hanks then the jib can be attached or removed from the forestay without disconnecting the forestay at the bottom. Snaps have been known to come undone, particularly if the spinnaker pole uphaul or downhaul catches on them.

Though it may seem cumbersome to someone not familiar with the stuff luff system, I highly recommend it. The use of a zipper-luff jib eliminates most of the disadvantages of this setup and the reduction in mast compression, and associated reduction in jib luff sag, make the boat faster.