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Understanding yacht rigs



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What is the issue?
The rig of a sailing yacht is the primary source of propulsion and it can be considered the equivalent in importance to the engine in a ship, or motor vehicle or indeed an aeroplane. But just as there is an enormous range of engine types for various applications, so there are many variations of sailing rigs which offer different properties and trade-offs to the user. This can be somewhat confusing.

Why address this?
Like these other modes of transport, if the primary means of propulsion is not correctly chosen, unsuitable for the job, or just not well understood, disappointment and perhaps maybe even danger will result. A broad understanding is well worth the short amount of time it takes to acquire.

How to address this?
The below overview aims to provide a quick guide to the most popular rigs used in sailing vessels. It is an area of constant development but the popular structures we see today should remain broadly the same.


Sloops fall into two distinct categories, fractional and masthead rigs
Image: CC0


BERMUDA SLOOP

The Bermudan sloop is a single-masted and mainsail boom rig, with just two sails, a foresail (also known as a headsail, jib or genoa) and a mainsail. The rig has been called the Bermuda rig, or Bermudian rig, because it was developed in Bermuda in the 17th century. It is also sometimes known as the Marconi rig because Guglielmo Marconi's wireless radio masts resembled the wires that stabilize the mast.

This set-up is by far the most popular as it is simple and, relative to other rigs, requires fewer spars and standing rigging. This makes it more economical to purchase and provides for lower associated maintenance and replacement costs. Sloop rigs fall into two distinct categories, masthead, fractional rigs defined by the position at which the forestay is attached to the mast.


The very popular masthead rig
Image: Tequask via CC ASA 4.0

Masthead Rig: This configuration is very popular due to the simplicity of its rigging arrangement. On a masthead rig the forestay is attached at the very top of the mast which allows the headsails to reach the same vertical height as the mainsail. Traditionally the masthead rig has a relatively short footed mainsail with a large overlapping headsail. Most of the rig's power comes from its vast headsail.

Masthead rig sloop advantages:

  • • With all the standing rigging meeting at the masthead the mast is well supported and only subject to compression forces.

  • • This simple configuration is relatively easy to set-up, sail with and maintain.

  • • Very efficient for sailing into the wind as a result of the long genoa luff and efficient slot.

  • • Large masthead spinnakers with their large area provide plenty of power but can prove to be a handful in strong winds.

Masthead rig sloop disadvantages:

  • • Requires a large sail wardrobe of headsails to cope with a range of conditions. This has been resolved in recent times by head-sail furling systems where some performance is sacrificed for convenience of handling.

  • • Efficiency is lost when the sail is reefed due to the widening of the slot and the poor shape caused by furling systems.

  • • Its large size headsails are more difficult to manage.

  • • Its large masthead spinnakers are more difficult to manage.

A variation of the standard sloop is the double-headed rig comprising a high clewed jib or yankee set foremost and a staysail whose tack fitting is further aft.


Fractional rig sloop
Image: CC0


Fractional rigged sloop: A fractional rigged sloop has its forestay attached at a point below the top of the mast and on its forward face. This leaves the top section of the mast unsupported from forward but with the ability of tension the backstay to bend the top section of the mast. This enables the mainsail to be flattened to improve performance by raking the upper part of the mast aft. With smaller headsails and longer footed mainsails the fractional rig derives most of its power from the mainsail and its shape is trimmed to balance the boat.

Fractional rigged sloop's advantages

  • • More emphasis is put on depowering the mainsail which is much easier and quicker to reef than changing a headsail.

  • • Fewer and/or smaller headsails are required to cope with a wide range of conditions which makes it easier for short-handed crews to manage.

  • • Smaller headsails to deal with and changes as the mainsail shape is altered to balance the boat.

  • • Downwind the larger mainsail gives more drive, and it's not so important if the smaller jib is blanketed by it.

  • • The jib can be taken in, especially so with a ¾ rig (where the forestay goes ¾ of the way up the mast) without the boat rounding up into the wind like a weather vane.

  • • Shorter hoists and smaller spinnakers to deal with as the halyard position is lower on the mast it reduces the heeling lever on the boat.

  • •The backstays can be tensioned to flatten sections of the mainsail, maintaining drive whilst reducing heeling moment.

  • • The distribution of sail area about the centreline of the boat provides a better balance which reduces the tendency to roll.

Fractional rigged sloop's disadvantages:

  • • Complicated backstay arrangments to control the bending of the topmast. This can be highly tuned for mainsail performance, but the vessel has to be actively and intelligently sailed.

  • • Fractional rigs can be fitted to cruising boats but they need aft swept spreaders
    (or rather their associated shrouds, which attach to the deck significantly aft of the mast alleviate the importance of the running rigging) to make them more manageable shorthanded and these sacrifice some upwind performance.

  • • Less durable and any error with the running backstays when tacking and jibing could risk damaging the rig or a dismasting.



CUTTER

The cutter, in its basic form, is essentially the same as the masthead Bermuda sloop with a single mast and mainsail, but it generally carries the mast further aft to allow for a jib and staysail to be attached to the inner forestay - not to be confused with the double-headed rig. The forward sail is called the yankee and the one slightly behind it is the staysail.

Cutter Rig
Image: mhobl

The head fitting for this sail is below the masthead and gains its fore and aft support from a set of running backstays fitted opposite the inner forestay attachment leading down at either side of the boat and at the gunwales, aft of the mast step. The cutter rig is typically seen on boats with a bowsprit, that have the staysail attached to the bow or with set-ups where the whole rig is contained inboard.


Cutter rig advantages:
  • • The sail area is split and so are the loads making this type of rig much easier to handle than a conventional sloop. When sloops increase over the 45 ft size or so, cutter rigs are often adopted to moderate the genoa areas, necessitating more power to sheet sails and larger winches to take the higher loading.

  • • Very easy to balance the sail area making it particularly good with windvane self-steering gear for long distance cruising.

  • • When the wind picks up it gives versatility to cruising boats, especially in allowing a small staysail to be flown from the inner stay in high winds. A small staysail set farther back on the boat and a reefed mainsail is a very solid arrangement for big winds.

  • • A staysail tends to make heaving-to easier.

  • • The added slot it provides enhances upwind performance.

  • • In heavy airs and large seas the 'runners' used to support the load of the staysail offer significant support to the mast in the fore and aft plane preventing the mast from 'panting'.

  • • The staying arrangement also offers an advantage as the inner forestay can act as a safeguard in the event of a forestay failure.

Cutter rig disadvantages:

  • • Tacking becomes complicated unless the staysail is equipped with a boom that enables it to be self-tacked - as it is usually a high aspect ratio with no overlap this may be catered for.

  • • Lacks the outright drive of a sloop rig in light weather conditions.

  • • The 'runners' required to provide mast support add more complication.

  • • With light winds aft of the beam the staysail is easily blanketed by the mainsail and its flapping disturbs the airflow into the genoa.


Traditional gaff rigged cutter
Image: CC0


The term 'cutter' is also used for any seaworthy vessel used in the law enforcement duties of the United Kingdom's Border Force, the United States Coast Guard or the customs services of other countries. This is on account of their descent from the Revenue Cutter Service of the eighteenth century.


KETCH

Ketches are similar to a sloop, but there is a second shorter mast and boom of unequal height astern of the mainmast, but forward of the rudder post. The second mast is called the mizzen mast and can fly a mizzen mainsail and a mizzen staysail. The forward mast is the taller and can be either masthead, fractional or cutter rigged and is known as the mainmast.

Ketch
Image: Remi Jouan via CC BY-SA 2.0


A ketch can also be cutter-rigged with two headsails. Generally, ketches will only be seen in the 40 ft. plus range of vessels which warrant the additional sailing hardware, and the reduction of sail sizes to the minimum.

Ketch rig advantages:

  • • This configuration is again a means of carrying a large amount of sail area while keeping each sail to manageable proportions.

  • • Offers better performance when reaching, especially with a mizzen staysail.

  • • In strong winds a ketch's mainsail can be dropped altogether (rather being reefed), thereby reducing sail and leaving a balanced sail-plan with just jib and mizzen set.

  • • When sailing with just mizzen and jib set, there is no excessive lee helm, and some claim that the additional sail allows a better balance. The sail plan is so good that, in an emergency, a ketch may be steered without the use of the rudder.

  • • When running before the wind or reaching across the wind, a ketch may set extra sails such as a spinnaker or mizzen staysail on the mizzen mast, as well as a spinnaker on the main mast.

  • • There’s a more nuanced control that is achievable through the assortment of trimming permutations.

  • • When at anchor, the mizzen sail may help to steady the boat, thereby reducing roll in an otherwise uncomfortable anchorage.

  • • The mizzen sail can help stabilize the boat under power.

  • • The mizzen sail may be flown alone to hold the boat's bow into the wind and oncoming waves whilst anchored or lying ahull with a sea anchor - a flat fully battened sail is most efficient for this use case as it will resist flogging and associated chafe.

Ketch rig disadvantages:

  • • It is not as efficient as the cutter rig because the mizzen sail is a relatively poor means of drive upwind and more of a balancing sail.

  • • When reefed, and sailing upwind, the mizzen mast and its associated rigging present a considerable drag.

  • • Downwind this sail is also a problem as it tends to blanket the sail plan forward of it.

  • • The mizzen mast is usually stepped in the cockpit with the result being an enormous amount of clutter and the rigging that gets in the way of the crew activities in all but the largest of yachts.

Both the ketch and the yawl rig have proved generally to be more suitable for motorsailers than the Bermuda rig.


YAWL

A yawl is a two-masted yacht similar to a ketch, with a shorter mizzen mast carried astern the rudderpost more for balancing the helm than propulsion. Compared to a similarly sized ketch, a yawl's mizzen mast is set further aft, its mizzen sail is smaller and it carries its mizzen sheet on a stern spar known as the bumpkin. A yawl's mizzen sail is very much smaller than its mainsail and is usually situated well aft, behind the helm station. As with the ketch rig the yawl's mainmast may also be masthead, fractional and or cutter rigged.

Yawl
Image: Don Ramey Logan via CC BY SA 2.0

The yawl rig has a profile that is similar to that of a ketch but with some further advantages:

  • • Similar to the ketch this configuration is again a means of carrying a large amount of sail area while keeping each sail to manageable proportions.

  • • But a yawl's smaller mizzen mainly serves to help trim and balance, working more as an 'air rudder' or trim tab rather than as a substantial part of the working sail area.

  • • Yawls tend to have mainsails almost as large as those of sloops and cutters with similarly sized hulls. The mainmast can be positioned further aft which allows a wider chain plate base thus reducing the compression loads in the mast.

  • • With the mainmast further aft the foretriangle can be larger allowing better light airs and windward performance.

  • • With the mizzen sail being generally smaller there is less of a sacrifice in downwind speed when the mizzen sail is lowered and less of a blanketing effect on the mainsail if it is left up.

The tight definition of a yawl, in relation to a ketch, is that the mizzen mast is positioned aft of the yacht's 'rudder post' and hails from Cruising Club of America rating rule. This distinction was developed following World War II to allow different styles of boats to race against each other with a handicap calculated from measurements of each boat.

Junk-rigged schooner
Image: CC0


JUNK RIG

The junk rig, also known as the Chinese lugsail or sampan rig, is a type of sail rig in which battens, much the same way as modern-day slab reefing, span the full width of the sail and extend the sail forward of the mast. Perhaps the oldest traditional type of sailing rig in existence today it has more or less retained its original form through the annals of time. The reasons for this are that it is an extremely well-balanced rig which is very simple to reef with no necessity to change sails.

Junk rig advantages:

  • • There is no need to point 'head to wind' when raising the sail. When the sheets are sufficiently eased, the junk sail will rotate around the mast to any point of the wind allowing the sail to be hoisted on any point of sailing.

  • • It provides considerable savings by not having to be maintained, tuned or replaced by an expensive rig.

  • • The junk rig is self tacking. None of the running lines need to be touched to tack the boat through the eye of the wind. Simply put the helm down, and the sails will swing over close hauled on the new tack.

  • • The mast is usually unstayed leaving a clear uncluttered deck.

  • • Because the sail is balanced the loads are relatively low and tackles are used in preference to winches.

  • • When running, the junk sail rig is at its best spreading a powerful wall of canvas far greater than a modern rigged boat, which will require a spinnaker to catch up. The junk rigged boat sails more easily downwind because of its self-jibing capability.

  • • Reefing a junk rigged sail is very easy. When sailing close to the wind, all that is needed is to ease the halyard. As the sail lowers by its own weight, the other running lines will also relax.

  • • Emergency furling is fast and simple. When the sheets and halyard are let go, the sail will blow downwind, drop into the cradle of the topping lifts, while being steadied by the full battens - this may make a mess to clear up subsequently.

Junk rig disadvantages:

  • • The rig simply cannot 'point' as close to the wind as other rigs.

  • • The sails do not generate as much power per square foot of sail area because of the flatness of the sail induced by its full battens - in a practice, the junk rig can usually overcome this by having larger sails.

  • • On the reach in very light winds, the flat sail shape is highly inefficient.

  • • The rigs unstayed masts are usually heavier and, from a spar manufacturer's point of view, are often a concern in terms of fatigue strength.

  • • The mast tends to whip in a choppy sea, especially when the sail is down and the boat is motoring.

  • • The rig has a higher number of control lines that are subject to chafe.

Although it is rarely seen on modern sailing vessels the junk rig is ideal for cruising sailors, particularly when sailing short- or single-handed. Most of the criticism of junk rigs comes from the racing circuit where the buoys are typically set to assure that the boats will battle directly upwind for half of the race. This point of sail emphasises the rig's weakest point makes it a much-disparaged non-contender.

Junk Rig cruising boat
Image: CC0


In a cruising environment, sailing upwind is anathema and many sailors seek the trade winds and maximize their downwind routes. In this cruising environment, the junk rigged yacht is fast, easy to use, and inexpensive to set up and maintain.

Cat rigged vessel
Image: Dennis Jarvis


CAT RIG

This is where a sailboat has a single unstayed mast carried well forward and a single sail. The traditional catboat has a wide beam, possibly a centreboard, and a gaff-rigged sail that can be considered to be a contemporary version of the junk with very similar properties. They have the Junk Rig sailing profile so that they do not perform as well as sloops.

  • • Cat rigs are simple to sail and manage. With one large sail and no rigging, a cat rig is up and running in moments and they can be managed single-handed quite easily.

  • • With a mast placed so far forward cat rigs can maximise the amount of salon space available.


With thanks to:
Michael Harpur SY Obsession
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