Junk Rig - Comparison With Bermuda Rig

Comparison With Bermuda Rig

The junk rig is a simple and effective rig. The rig contrasts starkly with the Bermuda rig which is prevalent on modern production boats. In its most traditional form the junk rig is carried on an unstayed mast (i.e. a mast without shrouds or stays, supported only on the step at the keelson and the partners) however standing rigging of some kind is not uncommon.

The cost to rig a boat with a junk rig would typically cost a fraction of the cost of a Bermuda rig, due mostly to the lower number of parts and adaptability of the rig to cheaper materials (especially the sailcloth.)

The junk rig typically produces less drive than a similarly sized Bermuda rig at low angles of attack (e.g. when sailing upwind, close-hauled) and this is especially pronounced in light wind. Performance close-hauled is perhaps the strongpoint of the Bermuda rig - key to winning a race with an upwind leg or outmaneuvering an opponent in battle.

The junk rig typically produces more drive than a similarly sized Bermuda rig when running downwind without a spinacker. A junk rigged boat can let its sails out athwartships (and beyond.) On a Bermuda rigged boat the shrouds interfere with sails if the sail was let out until it was athwartship. The full battens of a junk sail prevent the sail from collapsing when running in light wind (dispensing with the need for a whisker pole.) On double-masted junk rigged boats, the sails can be flown wing-and-wing (i.e. on opposite sides of the boat) even when on a broad reach as can a Burmudan rig. The junk rig is well suited to downwind travel with its working sails.

The junk rig appeals to shorthanded sailing crews for many reasons, especially because the rig reefs very easily. To lessen sail ("reef") all that is required is to let out the halyard. In contrast, reefing sail on a Bermuda rigged boat would typically require crew to move about the deck - which increases the chance of falling overboard, especially during a high sea state which is typical of conditions which would encourage reefing.

It is typical to run the halyards (lines used to raise and lower the sail) and sheets (lines used to trim the sail) to the companionway on a junk rigged boat. This means that typical sailhandling can be performed from the relative safety of the cockpit, or even while the crew is below deck.

Junk sails are typically carried on a mast which rakes (slants) forward a few degrees from vertical, which can look odd to the unitiated. The forward rake of the sail encourages the sail to swing out, which makes the use of a preventer unnecessary. Another way to say this is that the sail is stable when swung out and doesn't return to the middle of the ship when the wind drops.

Other benefits of the junk rig over the Bermuda rig

• Less flogging of sails (quieter)
• Less danger of an accidental jybe due to balance of the sail
• Less danger from an accidental jybe with a lighter-weight boom (lowest batten),although in Burmudan cruising boats the boom is usually tied to the rail for long distance downwind sailing
• More options when reefing - more "reef points"
• The sail can be constructed by an amateur - the cut is entirely flat

Other shortcomings of the junk rig compared to the Bermuda rig

• The shape of the sail depends on the flex of the battens, and the battens do the opposite of what would be most desirable: they bend only a little when the wind is light, and they bend a lot when the wind is strong. Consequently the airfoil developed in light wind doesn't have enough chord length to develop much lift at low wind speeds. Perhaps the chief shortcoming of the junk rig is that it typically produces poor drive to windward in light winds.
• The sail may remain almost entirely flat in light winds and develop unacceptable drive to windward
• The fully battened sail is much heavier than a sail made entirely of sailcloth with modern battens.
• The stiff junk battens disturb laminar wind flow over the sail -especially important when sailing to windward, or a point free.
• Junk sails are very low aspect ratio, giving less lift to windward.
• A junk sail has more running rigging aloft, adding to weight, providing more wind resistance and disturbing wind flow.
• A junk mast is normally of solid wood and very heavy for its short length.