Do boat owners make rational choices when they opt for a certain type of rig, or is sentiment and romance involved? This article explores the options.
Except on a few some might say eccentric designs, sails are not set singly but in combinations. Each sail acts individually as an aerofoil and also in concert with its fellows. The entire sail plan, viewed as a whole, can be considered to have a collective characteristic so far as lift, drag, heeling and drive are concerned – in effect acting as a single foil.
The well designed modern rig is a marvel of efficiency and flexibility. But, human nature being what it is, we continue to strive to re-invent the wheel. Scores of dotty ideas have sprung up over the years, claiming all manner of advantages; but fabric sails, controlled by ropes and hung on aluminium spars, still remain the firm favourite.
The ideal cruising rig should provide:
*** Good aerodynamic performance on all points of sailing. Clearly, the more efficient a rig is, the less sail area (and cost, weight and windage) you will need to drive the boat forward. Most rigs perform acceptably off the wind – it’s on the beat to windward where the real gains are to be enjoyed.
*** Adaptability for different wind strengths, either by reefing or changing sails. Reliability, convenience of operation and crew security are important considerations.
*** Ease and precision of control. There’s no point in having a superbly cut sail if you can’t trim it properly. On a centre-cockpit cutter I recently sailed, the correct sheeting position for the staysail was a point in space inboard of the cockpit coaming. Once we had rigged a barber hauler, the sail set splendidly but it became difficult to move about the cockpit without first training as a limbo dancer.
The virtues and vices of any rig are determined by both its general and detailed design. Let’s compare the most common cruising rigs:
The archetypal yacht rig, having a single mast which carries a mainsail and a headsail. This is a deservedly popular arrangement, offering simplicity and efficiency at the least practicable cost.
Sloops come in two variants: ‘Masthead’ , the most common, where the forestay goes to the top of the mast, and ‘fractional’ where it attaches at some distance beneath it. Aerodynamically both types are powerful performers to windward.
The simple features of the masthead rig are well understood, but the less obvious advantages (as some would claim) offered by the fractional rig deserve mention. These are:
*** The mainsail is the easiest sail to control and forms a greater proportion of the total sail area on this type of rig.
*** Headsails and spinnakers are smaller. Weaker crews can handle them with lighter gear. And when stowed below they take up less space.
*** Tensioning the shorter forestay is easier, improving headsail set and the efficiency of roller reefing gears.
When not under spinnaker or cruising chute, the fractional rig is comparatively better downwind. The big mainsail provides most of the motive power, and it’s less important if the headsail is blanketed.
For the gung-ho gang, a fractional rig allows mast bend to be altered, thereby controlling the fullness of the mainsail. Although very much a racing technique, to flatten the main in heavy weather can be useful in cruising, delaying the point where you must reef.
On the debit side, a fractional rig usually requires swept spreaders, which are more tricky to tune, and running backstays which are considered just too much hassle by many cruising sailors.
Although the robust simplicity of the masthead sloop will probably make this the first choice for most sailors, the fractional rig deserves serious consideration for its own special benefits – and could actually prove the preferred option for some purposes.
Another rig with a single mast (Fig. D17], the cutter has always been popular among long-distance sailors, and is today enjoying something of a revival in less epic circles. It can be slightly less efficient to windward than the sloop, but really comes into its own when reaching or running.
The distinguishing feature of the cutter is the staysail carried on an inner forestay. This division of the total fore-triangle area into two makes the individual sails smaller and easier to handle, but incurs some added complexity. Obviously, more gear is required to deal with two headsails, and both must be re-trimmed every time when going about – though the staysail can be made to self-tack with the use of a boom or athwartship track.
A hybrid arrangement (which once, but thankfully no more, laboured under the charmless name of ‘slutter’) can be either a sloop or cutter as required. Here the inner forestay could be detached and moved aside to clear the foredeck for tacking large genoas, and re-rigged when off the wind in heavier conditions.
The glory of the cutter lies in its versatility. In heavy conditions the jib (or genoa) could be struck or rolled up entirely. This not only reduces the total sail are but also effectively moves it aft where it can be more safely handled. This contrasts with the sloop where, say, the storm jib would remain hanked on right forward on the exposed foredeck. (See Storm Canvas for more on heavy weather sailing.)
Another advantage is that the mast is extraordinarily well supported. The deep reefed main (or storm trysail) is within the running backstays and can be tacked without first releasing the leeward runner. The security of the cutter rig is tremendously reassuring for the voyager – one of the many reasons I chose it for myself for Shindig.
Although probably not worth all the extra trouble in very small yachts, or if you intend to sail mainly in confined waters, the cutter is a very serious cruising offshore in boats upwards of, say, thirty-two feet [9.75m] LOA.
Ketch & Yawl
Both two-masted rigs, beloved by those who fancy its big boat appearance, ketches are often a romantic rather than a rational choice – though they make much more sense as boat size increases.
Ketches are relatively poor performers to windward. When beating, the mizzen can be so severely back-winded by the mainsail as to be virtually useless. Indeed, on this point of sailing they can almost be looked upon as under-canvassed sloops. But once the wind frees, the ketch starts to fare better. In light weather, mizzen staysails (or even mizzen spinnakers) can be set, adding useful sail area. The same rarely applies to yawls with their shorter mizzen masts.
Another advantage is that the fore-and-aft spread of the rig contributes to good balance, with plenty of scope for adjustment to keep helm loads light. In heavy conditions a favoured arrangement is to sail with just a headsail and mizzen set. And at anchor with just the mizzen set and sheeted amidships, the ketch or yawl will lie as serenely as a slumbering duck. One serious downside for the offshore sailor is that the mizzen can interfere significantly with any windvane self steering gear mounted on the transom – sometimes by downright impeding the action of the vane and also by disturbing the airflow enough to confuse its sensing capabilities. For more on self steering gears go here.
Supporters of the ketch will often defend their choice by pointing out that the rig is less strenuous to handle because the sail plan is split into smaller, lighter units. But, whereas this might be significant on big boats, it’s hardly a factor for your typical family cruiser where even the largest sail is no problem for a reasonably fit crew.
The counter argument centres not just on the ketch’s dubious windward ability, but also on the weight and windage aloft and the extra pennies required to put it there. Personally, I believe that unless there are compelling reasons to the contrary, most smaller modern ketches would have made better sloops or cutters.
And what else? Not a lot is new – in principle at least. The Chinese lugsail (junk) and lateen rigs have been around for thousands of years, the schooner, yawl, and spritsail barge for centuries. All rigs have their devotees, otherwise they would have been long forgotten. And it would be a rash man who would be too dismissive about concepts that have served us so faithfully.
But for the recreational sailor, the modern type of sail plan is very hard to beat. Extruded aluminium spars, stainless steel standing rigging, and ropes of synthetic fibre might not twang the sentimental heart strings quite so potently as varnished spruce and tarred hemp, but viewed in purely practical terms they are miracles of convenience.
Progress from here will probably be incremental, drawing step by step on advancing technology. Perhaps the sailboard is the only truly new sailing innovation we have seen in the last half of the Twentieth Century. With its articulated mast and wishbone boom, and its amazing method of steering by varying the sail balance, it is stunning in its conceptual freshness.
Although these have been around for thousands of years – most notably on the Chinese junk rig – it’s only fairly recently that modern materials have made these an attractive proposition for the yachtsman. In engineering terms an unstayed mast is a simple cantilever which must withstand all the loads imposed on it by the strength of its section alone. Once built in timber or aluminium or the weight aloft can be prohibitive – often mitigated in many designs by making the mast heights short, thus producing stumpy, underpowered sail plans.
However, with the arrival of GRP, it wasn’t long before attempts were made to produce laminated hollow spars from this remarkable new boatbuilding material. At first these were only partially successful. The structural qualities of glass fibre and polyester resin aren’t ideally suited to this application and failures were frequent. Then came epoxy resins, which opened the door still further; but it was not until such high-strength reinforcements as carbon and aramid (Kevlar/Dyneema) fibres became available that the full potential began to be realised.
Today, most composite spar makers choose carbon fibre and epoxy, with which they fashion masts that combine immense strength with acceptably light weight. This has opened up a fascinating area of development that will increasingly impact the sailing scene as more designers first recognise, and then explore, this intriguing approach to cruising yacht rigs. Some believe that within a decade or so the conventional stayed rig, with all its struts and wires and other bits and pieces, will seem as outmoded as the early biplanes. Hmmm...
One advantage of unstayed masts is that they can be made very aerodynamically clean, with no rigging, spreaders, or other fittings generating unwanted turbulence. Another is that, apart from that attributed to weight, the punishing compressive loads of conventional masts don't occur – though the mast step and deck aperture must obviously be made very substantial to form a secure socket for your cantilevered stick. Less attractively, the inherent flexibility makes proper headsail tension very difficult to achieve. This limits all but downwind headsails to relatively small sizes or, as is often the case, the rigs use no headsails at all.
I think we shall hear a lot about unstayed masts in the future. Simplicity is always a worthwhile design goal and there’s an obvious visual and structural elegance about having something which will stand up on its own. Of course we still have much to learn, and the stayed rig has by no means outlived its usefulness, but my guess is that, for cruising yachts at least, the days of standing rigging could be challenged by this reworking of old technology.