A draft of an article that I had written for another purpose but which should start to answer your question.
The next topic in our ongoing discussion on selecting the ideal boat is rigs. Like most of the topics to date, there is no single universally ‘right answer’ when it comes to the topic of rigs. Boats are designed as systems and each of the various rig types have their purpose and are best suited to particular hull types, and applications. The quality of the design is also important as a poorly designed rig of any type can make for a miserable sailing vessel that is hard on the crew and the boat alike.
Cutter and Sloop rig
These are the most common rigs being produced today. In current usage these terms are applied quite loosely as compared to their more traditional definitions. Traditionally the sloop rig was a rig with a single mast located forward of 50% of the length of the sailplan. In this traditional definition a sloop could have multiple jibs.
Cutters had a rig with a single mast located 50% of the length of the sailplan or further aft, multiple headsails and in older definitions, a reefing bowsprit (a bowsprit that could be withdrawn in heavy going). Somewhere in the 1950's or 1960's there was a shift in these definitions such that a sloop only flew one headsail and a cutter had multiple headsails and mast position became irrelevant. For the sake of this discussion I assume we are discussing the modern definition of a sloop and a cutter.
Historically, when sail handling hardware was primitive and sails were far more stretchy than they are today, the smaller headsails and mainsail of a traditional cutter were easier to handle and with less sail stretch, allowed earlier cutters to be more weatherly (sail closer to the wind) than the sloops of the day. With the invention of lower stretch sailcloth and geared winches, cutters quickly lost their earlier advantage.
Today sloops are generally closer winded and easier to handle. Their smaller jibs and larger mainsail sailplan are easier to power up and down. Without a jibstay to drag the Genoa across, sloops are generally easier to tack. With less hardware sloops are less expensive to build.
Sloops come in a couple varieties, masthead and fractional. In a masthead rig the forestay and jib originates at the masthead. In a fractional rig, the forestay originates some fraction of the mast height down from the masthead. Historically, sloops were traditionally fractionally rigged. Fractional rigs tend to give the most drive per square foot of sail area. Their smaller jibs are easier to tack and they reef down to a snug masthead rig. Fractional rigs place a lower stress on their hulls and often get by with lighter rigging and hardware for an equal structural safety margin. Today, fractional rigs are often proportioned so that they do not need headsails that overlap the shrouds making them even easier to sail.
One of the major advantages of a fractional rig is the ability, especially when combined with a flexible mast, to use the backstay to control mast bend and sail shape. Increasing backstay tension does a lot of things on a fractional rig: it tensions the forestay which in turn flattens the jib. Increasing backstay tension induces controlled mast bend, which flattens the mainsail and opens the leech of the sail. This allows quick depowering as the wind increases and so allows a fractional rig to sail in a wider wind speed range without reefing, or making a headsail change than a masthead rig, although arguably requiring a bit more sail trimming skills.
While fractional rigs used to require running backstays, better materials and design approaches have pretty much eliminated the need for running backstays. That said, fractional rigs intended for offshore use, will often have running backstays that are only rigged in heavy weather once the mainsail has been reefed. The geometry of these running backstays typically allows the boat to be tacked without tacking the running backstays.
Masthead rigs came into popularity in the 1950's primarily in response to racing rating rules that under-penalized overlapping jibs (genoas) and spinnakers and so promoted bigger headsails. Masthead sloops tend to be simpler rigs to build and adjust. They tend to be more dependent on large headsails and so are harder to tack and also require a larger headsail inventory if performance is important. Mast bend is harder to control and so bigger masthead rigs will often have a babystay that can be tensioned to prevent pumping and induce mast bend in the same way as a fractional rig does. Dragging a Genoa over the babystay makes tacking a bit more difficult and slower. While roller furling allows a wider wind range for a given Genoa, there is a real limit (typically cited 10% to 15%) to how much a Genoa can be roller furled and still maintain a safely flat shape. As a result, masthead rigged boats generally require larger sail inventories.
Cutters, which had pretty much dropped out of popularity during a period from right after the end of WWII until the early 1970's, came back into popularity with a vengeance in the early 1970's as an offshore cruising rig. In theory, the presence of multiple jibs allows the forestaysail to be dropped or completely furled, and when combined with a reefed mainsail, and the full staysail, results in a very compact heavy weather rig (similar to the proportions of a fractional rigged sloop with a reef in the mainsail). As a result the cutter rig is often cited as the ideal offshore rig. While that is the theory, it rarely works out that the staysail is properly proportioned, (either too small for normal sailing needs and for the lower end of the high wind range (say 20-30 knots) or too large for higher windspeeds) and made of a sail cloth that makes sense as a heavy weather sail but which is too heavy for day to day sailing in more moderate conditions or out of a sail cloth too light for heavy going. Also when these sails are proportioned small enough to be used as heavy weather sails, these rigs will often develop a lot of weather helm when being sailed in winds that are too slow to use a double reefed mainsail. Like fractional rigs, cutter rigs intended for offshore use, will often have running backstays that are only rigged in heavy weather once the mainsail has been reefed. Unlike the fractional rig, when the running backstays are deployed, the geometry of these running backstays typically requires that the running backstays be tacked whenever the boat is tacked.
Cutters make a less successful rig for coastal sailing. Generally, because of their offshore intent, cutters tend to have snug rigs that depend on larger Genoas for light air performance. Tacking these large Genoas through the narrow slot between the jibstay and forestay is a much harder operation than tacking a sloop. As a result many of today's cutters have a removable jibstay that can be rigged in heavier winds. This somewhat reduces the advantage of a cutter rig (i.e. having a permanently rigged and ready to fly small, heavy weather jib).
Cutters these days generally do not point as close to the wind as similar sized sloops. Because of the need to keep the slots of both headsails open enough to permit good airflow, the headsails on a cutter cannot be sheeted as tightly as the jib on a sloop without choking off the airflow in the slot. Since cutters are generally associated with the less efficient underbodies that are typical of offshore boats this is less of a problem that it might sound. Cutters also give away some performance on deep broad reaches and when heading downwind because the Genoa acts in the bad air of the staysail.
Yawls and Ketches:
As I said at the start of this discussion, boats are systems and when it comes to one size fits all answers, there is no single right answer when it comes to yawls and ketches either. A Yawl is a rig with two masts and the after mast (the mast that is further aft or further back in the boat) is aft of the rudder. A ketch is a rig with two masts, the after mast is forward of the rudder. Either rig can have either a single jib or multiple jibs. When a Yawl or a Ketch has multiple jibs it is referred to a Yawl or a Ketch with multiple headsails. It is considered lubberly to refer to that rig as a 'cutter ketch' or 'cutter Yawl'.
I lump yawls and ketches together here because the share many similar characteristics. Ketches, in one form or another, have been around for a very long time. In the days before winches, light weight- low stretch sail cloth, high strength- low stretch line, and low friction blocks, breaking a rig into a lot of smaller sails made sense. It made it easier to manhandle the sails and make adjustments. Stretch was minimized so the sails powered up less in a gust and although multiple small sails are less efficient, the hulls were so inefficient that the loss of sail efficiency did not hurt much. Multiple masts, along with bowsprits and boomkins, allowed boats to have more sail area that would be spread out closer to the water.
In a time of stone internal ballasting, and high drag in relationship to stability, this was important as it maximized the amount of drive while minimizing heeling. In theory, multiple masts meant more luff length and more luff length meant more drive forces to windward. But multiple masts also meant more weight and much more drag. There are also issues of down draft interference, meaning that one sail is operating in the disturbed and turbulent air of the sails in front of it, which also greatly reduces the efficiency of multi mast rigs.
Yawls really came into being as race rule beaters. They are first seen in the 1920's as a rule beater under the Universal and International rules. They continued to be popular under the CCA rule as well. Under these rules, the sail area of jibs and mizzens were pretty much ignored in the rating. This popularized the masthead rig and the yawl.
There was a basis for not measuring the sail area of a yawl under these rules. On a yawl going to windward, the mizzenmast and sail generally actually produce more drag than they do drive. This is because the mizzen is sailing in really turbulent air and has to be over trimmed to keep from luffing which can effectively act as an airbrake. This is slightly less of the case on a ketch where the size of the mizzen is large enough to provide a larger percentage of the drive.
Downwind mizzens also are a problem. In this case the mizzen is forcing the main or foresail to operate in their bad air and so again the mizzen is not adding as much to the speed of the boat as they are taking away. BUT in the predominantly reaching races that were typical of offshore races of that era they offered a number of advantages. First of all on a reach the sails are not acting in the slipstream of each other and so each contributes a fair amount of drive for the drag produced. Also with the advent of lightweight low stretch sailcloths, mizzen staysails, which are great reaching sails, came into widespread usage in racing. Here again a ketch has the advantage of having a taller mizzen and so can fly a bigger mizzen staysail.
It might be helpful to compare yawl and ketch rigs to sloops. The broad generalities are that for a given sail area a sloop rig will generate a greater drive for the amount of drag generated pretty much on all points of sail. That means that a sloop will be faster or will require less sail area to go the same speed. Sloops are particularly better than Multi spar rigs such as Yawls and Ketches on a beat or on a run. A sloop rig would tend to be taller for a given sail area. This means it would be better in lighter air but it potentially might heel more, or need to be depowered or reefed sooner as the breeze picks up.
Sloops work best on boats with reasonably modern underbodies. Both are more efficient and so can point higher and make less leeway.
Ketch and Yawl rigs work best with heavier boats with less efficient underbodies such as full keels and deeply Vee'd hull forms. These hull forms often need a lot more drive and the hull is the limiting factor in how fast or how close-winded the boat will be. The yawl or ketch rig's lack of windward ability is less of a liability when placed on a hull that similarly lacks windward ability. Also, the ability of a ketch or yawl to carry more sail with less heeling moment also makes it a natural for a heavier hull form which often has comparatively little stability when compared to the amount of drive required to make a heavy boat move.
Much is made of the ketch or yawl's ability to be balanced to help with self-steering, to heave to, or the ability to simply sail under Jib and mizzen in a blow. This is one aspect that a traditional ketch or yawl has over a traditional sloop. It is not so true of modern sloops. Modern (especially fractional) sloops can be easily depowered and that reduces the need to reef. With modern slab reefing gear, reefing is far more easily accomplished than dropping the mainsail to the deck on a yawl or ketch. In a properly designed sloop balance is just not all that hard to achieve.
The performance of all three rigs, both on broad reaches and in lighter air, can be improved by the ability to carry kites of different types.
In terms of comfort at sea, ketch and yawl rigs push the weight of the spars closer to the ends of the boat which can increase pitch angles, albeit, while perhaps slowing pitching rates. The taller rigs of a sloop tend to increase roll angles while slowing roll rates.
Then there are structural issues. It is often difficult to properly stay a ketch or yawl rig as the mainmast backstay often need to be routed around the mizzen and the forward load component of the mizzen if often taken by the top of the mainmast. It is also often difficult to get proper aft staying on the mizzen of a ketch or yawl as well. These structural issues are particularly pronounced on Yawls where the mast is so far aft in the boat that on a traditional boat it is hard to get adequate staying base widths.
Many of the early fiberglass yawls were very poorly engineered. I heard the story of how the Bristol 40 became a yawl. It seems that Clint Pearson (who owned Bristol) had started to build a Bristol 40 sloop on order for a particular customer. As the boat was nearing completion the prospective owner bailed out leaving Mr. Pearson with bit of a problem. Almost at the same time came an enquiry about the availability of a Bristol 40 yawl for prompt delivery for a different person. Without hesitation the potential buyer was told that they happened to have a yawl that was almost finished and would be available in a few weeks. Bristol was building a 24 foot Corsair and they took a mast and rigging from a Corsair and used that for the mizzen. A block of wood was glassed onto the hull for a mast step and a hole cut in the deck for the mast to go through and Voila- the Bristol 40 yawl. Several more were built like that and they quickly proved problematic. Eventually the design was engineered to solve the problems that occurred on the first few yawls.
You often hear people say that yawls and ketches are simpler rigs to handle. I am not clear why that is assumed to be so as there are more sails to trim and more interaction between the individual sails. As on a sloop, you start trimming from the forward most sail moving aft. Also as on a sloop, fine tuning, small adjustments are made moving forward again to reduce downdraft interference between the sails. Sailed with the same degree of precision, a ketches and yawls require more fine tuning than a sloop but on the whole about the same amount of fine tuning as a cutter.
Anyway, in conclusion, if you are interested in sailing performance or ease of handling, a sloop rig makes more sense. To me the only justification for the yawl rig today is solely romantic charm, or a sense of history. I do not mean this to be a put down to those who love historic rigs, but for sheer sailing ability a yawl or ketch is a relic of another time, or an obsolete racing rule. Still, if you live in an area that is typically windier and you like traditional boats, then a ketch or yawl is an interesting albeit complicated rig.
Schooners, more than any of the other fore and aft rigs, are really a series of rigs. They vary from the modern unstayed cat schooners (like the Freedom 39), to Fenger's experiments with wishbone schooners, to the traditional two-masted gaff schooners, to the early 19th century square topsail schooners, to the knockabout and the staysail schooners of the late 1930's, to the 4, 5 and 6 masted cargo schooners of the early 20th century. Each of these has distinct advantages and disadvantages.
By definition a schooner is a rig with two or more masts with the after mast(s) equal or taller than the forward mast(s).
Schooners, in one form or another, have been around for a very long time. Like most multi-masted rigs, they evolved in the days when breaking a rig into a lot of smaller sails made sense. Multi-masted rigs resulted in a rig with a greater number of smaller low aspect ratio sails. These proportionately smaller sails reduced stretch within the individual sails, made it easier to manhandle the sails and make sail shape adjustments. This was a time before winches, light weight- low stretch sailcloth, high strength- low stretch line, and low friction blocks. These proportionately smaller sails powered up less in a gust. While multiple small sails are less efficient, the hulls of the era were so inefficient that this loss of sail efficiency did not hurt much.
Multiple masts, along with bowsprits and boomkins, allowed boats to have more sail area that could be spread out closer to the water. In a time when stone internal ballasting was the norm, this was important as it maximized the amount of drive while minimizing heeling moments. Multiple masts meant more a little more luff length and more luff length meant greater drive force on a reach or beat. But multiple masts also meant more weight aloft and much more aerodynamic drag increasing heel some and greatly reducing the relative efficiency of the sails. Multi mast rigs also have the issue of downdraft interference, meaning that each sail is operating in the disturbed and turbulent air of the sails upwind of it, which also greatly reduces the efficiency of multi mast rigs. .
Schooners are best suited for burdensome vessels with comparatively little stability. They are best used in sailing venues where they predominantly will be reaching between 30 degrees above a beam reach to approximately 50 degrees below a beam reach. Because of the geometry and inherently high drag of the schooner rig they are not very good rigs upwind or down. Upwind, the large amount of aerodynamic drag from the spars and, in stayed rigs, rigging, coupled with the typically low aspect ratio sails typical of a schooner rig, and the down-drafting problems of a multi-masted rig, results in very poor windward performance. When compared with Yawls, which can drop their mizzen when beating without much consequence, a Schooner's primary drive sail(s) are acting in the wind shadow of the entire rig.
Probably the highest upwind efficiency is achieved in schooners with lug foresails. On a schooner, lug foresails are not actually 'lug rigged'. In the case or a schooner, the term 'lug foresail' means a gaff foresail (not a jib) that foresail that over laps the mainsail in much the same manner as a Genoa over laps the mast on a modern rig. This rig was common in American working craft in the 19th century partially because there was no boom to deal with on the working deck. It was used on such boats as the yacht America's original rig, Tancook Whalers and on many Atlantic coast pilot boats. Lug foresails need to be tacked around the mast in much the same manner as a Genoa is today.
Downwind the problem of downdraft interference is a major problem as well. The large mainsail again tends to block the air on the sails forward of it and schooners really do not have a tall forward mast on which to fly a meaningful spinnaker. While there are all kinds of kites that can be flown from a schooner, and early working schooners often carried square sails on their foremasts, most of these patches really come into their own on a reach.
I once had a great conversation with Olin Stephens about schooners. Someone had asked why the schooner rig had died out. In the course of the conversation it was pretty much concluded that as hull forms became increasingly efficient, the schooner rig could not keep up. Great efforts at all kinds of rig improvements were tried but in the end the inherent limitations of the schooner rig was ill matched to the improved hull forms of the early 20th century.
Today, traditional schooners are wonderful to look at relics of a bygone age. Traditional forms of the schooner rig are complicated rigs that are expensive to build and maintain. They generally lack the strength of staying of a more modern rig. They are limited in their ability to beat to windward, hove to, or go dead downwind. They require greater skill to sail well and are pretty labor intensive to sail in shifting conditions. Still there is nothing like the romance of gaff topsail schooner with a bone in her teeth.
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Curmudgeon at Large- and rhinestone in the rough, sailing my Farr 11.6 on the Chesapeake Bay
Last edited by Jeff_H; 01-14-2011 at 01:09 PM.