Preparation

THE SIMPLE TEMPEST

To sail a Tempest effectively you need not only the basic standing and running rigging but also a means of tensioning the standing rigging, controlling sail shape, and handling the spinnaker in all wind conditions.

You can buy a fully equipped new boat beautifully laid out (as in Figure 8), but if you’re starting with a bare hull or an older boat that hasn’t been kept up to date, you should examine its basic layout with the following points in mind.

NECESSARY EQUIPMENT

Assuming it has all the equipment the class rules require (including a compass and a traveler that extends "beyond the bridge deck moulding and onto the side decks") plus standing rigging, trapeze, sheets, and halyards, you’ll need the following to make your boat competitive.

A means of tensioning the forestay after the jib is hoisted. While you won’t need to adjust forestay tension under way, initially it must be sufficient to bend the mast through compression—about 160kg. Alternately, you can use a heavy wire in the jib luff so that the jib halyard, not the forestay, tensions the rig (see page 15).

A means of preventing the mast from bending too much under compression. A lever that pivots at the partners provides positive control. If this isn’t available, however, you can wedge wood blocks in the partner forward of the mast to achieve a similar effect.

A mainsail outhaul and jib downhaul that you can tension in a "set it and forget it" fashion when you’re under way.

Traveler, main cunningham, backstay, and vang that the helmsman can easily control, whether inside the boat or hiked out.

A spinnaker pole topping lift that the helmsman can adjust from inside the boat (e.g., in light air).

A means of retracting the topping lift when you take down the spinnaker pole. This system should incorporate a stop that keeps the pole from lifting too high in heavy air on a tight reach. As you won’t need to adjust it otherwise, you can simply attach the wire downhaul to a shock cord. Figure 9 shows such an arrangement.

DESIRABLE EQUIPMENT

There are many options that will make your boat more convenient for racing, although they’re not necessary for recreational sailing. These are described beginning on page.

UNNECESSARY EQUIPMENT

Finally, you may see the following additional items on some older boats, but you shouldn’t need them for racing.

A means of tightening the forestay when the jib halyard (rather than the forestay) tensions the mast. The forestay is needed only to conform to the class rules in this situation, and can be shock cord loaded to remove any slack.

A means of adjusting shroud length under way. Gear that performs this function goes back to the days when some Tempests carried so much rake upwind that they were slow downwind unless the mast could be straightened. Standard turnbuckles will do, provided you’ve raked the mast correctly in the first place (see page 19).

Roller reefing for the jib. A Tempest is very slow when sailed dead downwind, and the jib won’t interfere with the spinnaker on any higher point of sail.

A means of adjusting the jib sheet leads while you are hiking out. Jib sheet turning block location has become a "set it and forget it" item.

THE STANDARD TEMPEST

BACKGROUND

Before the 1972 Olympics, adjustable hardware was common because optimal jib lead location, forestay tension, and mast rake settings weren’t known. By the 1976 Olympics, top sailors had discovered these settings, so simpler boats had begun to dominate world competition.

Since then, these settings have been publicized (see Appendix E). Hence, although the class rules allow extreme freedom in hardware selection and location, two "standard" layouts have evolved, one in Europe and the other in North America (described here). These layouts:

enable people of all sizes and strengths to compete on equal terms at the championship level;

make competitive sailing possible for inexperienced skippers or crews;

utilize readily available standard fittings to minimize original hardware expense;

and virtually eliminate failures and the need for maintenance: "everything works all the time."

MAIN SHEET SYSTEM

Components include:

a 35–40 ft. (finished length) 3/8-inch diameter sheet;

a double block with a becket for the traveler, three single blocks for the boom, and a fourth single block for the cleat assembly. (While some boats have a 5:1 main sheet, this 6:1 arrangement requires much less strength, yet can be trimmed as quickly as needed); and

a cam cleat assembly mounted on a pedestal aft of the bridge so that stray lines won’t catch in the turning block there (see Figure 10).

The main sheet should cleat conveniently enough to encourage relentless adjustment. You may not need a ratchet block after you learn to use the cleat without looking at it. The Harken cleat assembly is one that allows you to choose a cleat angle you like. If you still want a ratchet, mount it as the aft block on the boom, where it can’t "eat" other lines when you trim it.

Mount the boom blocks far enough aft so that the net force of the mainsheet when trimmed is perpendicular to the boom. This prevents the boom from transmitting unwanted fore-aft pressure to the mast. Also, cluster the blocks within 30–40cm inches on the boom. Otherwise, you’ll lose much of the system’s mechanical advantage when you need it most—to trim hard.

Mark the sheet about 70 inches from the becket (see Figure 10) with an indelible mark or a colored whipping from an unused line (better because it won’t fade) so you can reproduce trim from one beat to the next. A double mark about 55 inches from the becket will provide extra "visibility at a glance."

From the becket, feed the sheet (1) forward-to-aft through the middle boom block, (2) aft-to-forward through the double block, (3) through the forward boom block, then (4) forward-to-aft through the double block, etc. Otherwise (i.e. if both parts of the sheet travel through the double block in the same direction), the sheet may jam in the double block when trimmed while slack.

Tie down the main sheet’s aft end so it won’t knot or tangle.

JIB SHEET SYSTEM

Components include:

cleats mounted on the bridge "table";

cheek ratchet turning blocks mounted on the side tanks athwartships of the cleats; and

free-standing turning blocks that fix the fore and aft sheeting angle.

Offset each cleat to its own "weather" side so you can differentiate it at a glance (look closely at Figure 8, page *0). Bolt them through a 1½-inch thick support to elevate them above the bridge-table surface. With this arrangement:

both the helmsman and crew can easily cleat and uncleat the sheet, independently or together, upwind and down, in light air (when both are huddled down in the boat) and heavy air (when both are hiked out in alignment with the sheet); and

the crew can leave the jib cleated until he or she has come in from the trapeze, confident that it will easily release, even in heavy air.

Commodore-sized "Jumbo" clam cleats in combination with a 35 ft. long 9/16 inch diameter one-piece sheet, with a figure-eight knot through the jib at each end, have become the most popular arrangement because:

the large cleats provide good "targets";

the sheet will hold reliably unless the cleats are worn (aluminum cleats last much longer than plastic, incidentally);

the sheet will release reliably, even when "ripped" out of the cleat under strain; and you can differentiate the sheet at a glance because it’s larger than any other line on the boat, and it can be of a color different from any nearby line.

Mount the ratchet blocks inboard-outboard to avoid interference with the spinnaker sheets. Through-bolt them to backing plates (e.g., phenolic) for strength. (Many manufacturers build in these plates.) Note: The ratchets in some brands engage only under load, allowing a released sheet to shoot out through the block against the pawl quickly and without unnecessary wear.

The exact locations of the free-standing blocks depend upon mast rake, jib tack position, and the length of the jib leech. (Most jibs are cut up to four inches shorter on the leech than the class rules allow to accommodate proper mast rake.) As proper positioning of these blocks may vary from sail to sail, you may need to provide initial adjustability by through-bolting one-foot-long tracks to the cockpit tanks. Mount their aft ends athwartships of the chainplates and use backing plates. Later, under sail, you can slide the blocks along these tracks until you find the best position (see page 21 for additional discussion).

SPINNAKER SHEET SYSTEM

Components include:

a 12 ft. long ¼-inch diameter twing line with bullet blocks at each end, running through cleats and eyestraps mounted on deck just forward of the chainplates;

turning blocks through-bolted to backing plates near the gunwales, athwartships of the aft edge of the hatch opening;

outward-facing cheek clam cleats mounted on the aft deck at the corners of the cockpit;

cheek ratchet turning blocks through-bolted to backing plates inboard and aft of the chainplates;

cam cleats at the inboard edges of the tanks, aligned fore-and-aft to match the ratchet blocks, mounted on thin inserts to allow easy, but never accidental, cleating from the trapeze; and

a one-piece ¼-inch diameter sheet long enough to allow a comfortable amount of slack when played from the trapeze. The length of a one piece sheet should be [74 feet] – [2 x the fore-and-aft distance between the forward turning blocks and the chainplate] + [4 x the distance of the aft deck block aft of the after edge of the hatch cover]. 72 feet is about right, depending on its path around the boat. Boats with spinnaker launchers need approximately six feet more.

The ratchet block locations enable the crew always to face forward when playing the spinnaker, even in light air, and keep the sheet from fouling when the crew is out on the trapeze. Mounting the ratchet blocks forward also enables the crew to turn the ratchets on and off, and the sheet will transmit more "feel" than it could if it had to turn 180 degrees through aft-mounted ratchets.

The aft cleats are so located that the helmsman can use them without looking (after hoisting and gybing when using his/her legs to steer. Also, he/she never sits on the sheet because of the "hiking pad.") Later, the crew can simply pop the sheet out of the "skipper’s" cleats by trimming it normally.

TRAVELER SYSTEM

A self-contained "automatic" traveler incorporating cleats on the traveler car is now commercially available, e.g., from Harken. The leeward cleat in this system automatically releases the traveler line when the windward cleat grabs it. Most people who try it wonder how they ever managed without it.

"Normal" traveler systems typically consist of:

a 20–25ft. long 5/16 inch line;

clam cleats mounted on the aft face of the bridge approximately one foot inboard of the edge of the side "tank." A metal or wood "bracket" provides flexibility in installation;

a car mounted on a track extending to the side deck on both sides (as the class rules require);

"guards" (e.g., wood carved to fit) that keep the main sheet from catching on the end of the track, and optional shims that elevate the ends of the track; and

turning bullet blocks at the end of the track.

You want the traveler to work as conveniently as the main sheet. You can use your back muscles, not your arm muscles, when you trim the traveler if you mount the cleats inboard as described above. Most boats use a 2:1 traveler. You can also use 3:1, which requires much less strength.

CONTROL LINES

Key principles are:

make all lines "endless" or tie them down so they can’t knot, suck through bailers, etc.; and

avoid gaining mechanical advantage where blocks can catch and interfere with one another (e.g., along the cockpit floor).

Controls that the helmsman may want to adjust when hiked out should lead to the sides of the aft face of the bridge, e.g.:

mast straightener (gains 2:1 at the bottom of the mast lever);

cunningham (gains 4:1 along the aft face of the mast); and

vang (gains 2:1 at the bottom of a 3:1 lever vang, or 6:1 via turning blocks).

Controls that the helmsman doesn’t normally adjust when hiked out may lead to the center of the bridge, e.g.:

mast bender (connected directly to the bottom of the mast lever);

topping lift (connected directly to the pole hook); outhaul (4:1 gained internal to the boom);

jib halyard fine adjustment (3:1 for luff tension); and

forestay (16:1 via a magic box for rig tension).

Select ¼-inch color-coded line for all controls, e.g., the center controls on the bridge are (left to right) mast bender (orange), topping lift (green), outhaul (blue), jib halyard fine adjustment for luff tension (red), and forestay for rig tension (white); the outside controls are mast straightener (orange) and cunningham (blue); and the lower cleats on the aft face of the bridge are for the vang (blue).

THE COMPLETE TEMPEST

On a poorly equipped Tempest, racing isn’t really fun. You don’t get used to awkward fittings; they merely become more irritating with time. On a well-equipped Tempest, however, nothing wears out the crew or functions poorly. You don’t worry about endurance. Some of the details that make such a boat are listed below.

FOR THE HELMSMAN

A means of adjusting vang tension from a hiked out position, arranged to enable instant release to prevent broaching on windy reaches.

Backstay — The mast should be able to survive without one, and if your sails are cut properly, you may not need one for sail trim. However, a backstay gives an invaluable "reference in the sky" for sail trim when racing, and many people use a backstay for this one reason.

A clothesline reel for retracting the spinnaker halyard when it’s hoisted. If you don’t have one, tie the end of the halyard to any fitting in the boat so that the only knots that can form are slip knots.

A masthead fly — Some top boats don’t have them because their owners never look up that high. Other boats don’t use them because they get tangled in the hoist during launching. But they’re useful when you’re trying to select the proper trim for the spinnaker guy, and some have stationary rays that you can use to judge gybing angles.

A forward-mounted compass — While the Germans use a bracket aft of the partners, other boats have a surface-mounted compass—no recessed hole (it’s illegal)—on the foredeck just forward of the mast on the centerline. These arrangements (1) enable both skipper and crew to sight along the center lubber line and (2) keep the compass in the skipper’s field of view. If you find these locations too distant to see clearly, however, you can mount a single compass at the bridge or twin compasses on the side decks. Beware, however, of misleading readings due to the proximity of the keel!

A non-slip tiller extension — There are many ways to eliminate "white knuckle steering" on cold wet days. Spiral-wrapped rubber tape (e.g., tennis racket handle tape) is an effective and durable solution. Wrap it starting at the universal joint, stretching it as you work your way out to the end and taping it at short intervals with electrical tape.

A means of keeping the tiller from scraping the lazarette cover — When this is a problem, a small piece of neoprene wedged between the tiller and rudderhead assembly can be a simple solution.

Padded hiking straps — Inserting the webbing through foam pipe insulation will keep your ankles from chafing. The insulation can abrade, however, so you may have to sew a cloth cover over it.

A centerline foot stop screwed through the deck between the mainsheet cleat and the aft bulkhead (see Figure 8, page *) can keep you from sliding down into the bilge when the boat heels over too much.

Hiking pads — 3/4-inch foam dipped in vinyl (a technique used to make athletic padding) secured by velcro to the tanks with their outside edges along the path of the spinnaker sheets as shown in Figure 8, page * will give the helmsman a luxurious feeling and prevent him from sitting on the sheet.

A means of opening the leeward bailer from the windward side can save you from having to dive into the leeward bilge after a wave has come over the bow. Lead a small line leading aft from the bailer, then across the aft cockpit bulkhead to a cleat the skipper can reach. Run a shock cord forward from the bailer for automatic closing.

A weed stick, e.g., a light fishing pole that the crew can stab into the water to scrape off weeds from the keel or rudder; not often needed, but vital when it is.

FOR THE CREW

A trapeze harness that’s comfortable all day, in any weather. Every brand of harness doesn’t fit every person. A good one will support your back, both down low and in the shoulders when you lean back into it, without binding in the crotch. If you have one that does bind, try loosening it. And in any case, don’t be content with an uncomfortable one.

Easy-to-hold trapeze handles — Good ones virtually grab you! Their diameter is easy to grip and they provide maximum friction. Poor handles such as smooth, small diameter tubes will cause you, as crew, to mistrust your grip: you won’t want to go out without hooking up or to unhook before coming in. Use twine, friction paint (such as Liquid Carpet) or grooves (made in plastic handles with a soldering iron), and wear gloves to maximize friction.

Trapeze rings at the proper height (see dimensions in Appendix E). As crew, you can balance best when you hang low over the side, out of the wind, nearly hitting the waves, as if in a hammock. A too-high trapeze ring will tempt you to move forward or try to support too much weight with your legs, which will be tiring.

Twing lines (see Figure 11), which most people find easier to use than reaching hooks. You’ll need one or the other to lead the guy low around the shroud so the crew can use the trapeze without interference and so the pole won’t "sky" on windy reaches. If you have reaching hooks, don’t change unless you decide you like twing lines better. But if you’re starting from scratch, these are as easy to install as reaching hooks. If you mount the twings forward of the shrouds, the crew can brace a wrist against, the shroud when holding the guy in trim (see also pages 25 and 30).

Spinnaker pole stowage on the boom (e.g., large hoops aft that make an easy "target," and forward rings into which the crew can clip the end fitting), so you don’t have to shove the pole under the bridge before taking down the spinnaker.

Features that simplify spinnaker pole handling. There are a vide variety of devices in use, such as:

a downward-opening topping lift hook that "pops" back into the pole’s eyestrap when pulled over the top of the pole;

easy-opening end fittings with jaws that the crew can unhook from the mast ring by pulling down;

diamond stays that lead through the spinnaker pole ring on the mast (rather than straight down from the spreader tip to their termination point on the mast) so the pole won’t spring inside the diamonds when the crew removes it from the mast under load;

halyard cleats that grip automatically when the spinnaker is fully hoisted (by either the skipper or crew); and

spinnaker sheet cleats that enable the skipper and crew to exchange control without distracting one another.

PREPARING THE RIG

A new boat will be ready to race as delivered. When you need to rerig yours, however, here are some points to consider.

THE MAST

Construction — The class rules control the mast’s total weight, tip weight, taper, flexibility, and placement in the boat, but not its construction. Virtually all masts, however, are a stock aluminum section from Ian Proctor Metal Masts, Ltd., and, while there are some superficial variations, all post-1970 masts are functionally identical.

The class rules are very permissive regarding rigging. They state only that standing rigging must be "of circular section" and that a standing forestay shall be rigged "... on the centerline of the hull ahead of the luff of the jib and capable of supporting the mast with the sails lowered."

Forestay arrangements — Two forestay arrangements are popular. Before 1972, when many boats had roller reefing gear, a heavy wire inside the jib luff tensioned the rig under way, and a low windage (1/16 inch wire) forestay was led aft to a cleat or terminated in the bow compartment where a shock cord took up the slack.

This light forestay arrangement had two disadvantages, however. First, the jib halyard exerted a mechanical advantage of nearly 2:1 on the mast, causing unnecessary and disadvantageous compression bending that could be restrained only at the level of the partners. Second, when the jib was being hoisted in any breeze at all, it would sag back into the mast, which itself would be lurching around if the forestay wasn’t tight. There had to be a better way.

Olympic gold medalist Valentin Mankin of the Soviet Union found it. Ignoring the notion that windage must be minimized, he got rid of his heavy halyard and luff wire, hanked his jib onto a heavy wire forestay, and tensioned his rig with a control that pulled this forestay down. He used his light jib halyard to adjust luff tension.

Today, this heavy forestay arrangement has become universal on new boats, and sailors with older boats often convert to it when they replace their standing rigging, so it’s the one discussed in this guide.

Before you begin, depending on what you plan to accomplish, you’ll need a nicopress tool and sleeves, a coathook, a tape measure, a screwdriver, appropriate wrenches, a plumber’s "snake," and a fid if you intend to splice the halyard tails in place.

You’ll also need a work space large enough to allow you to rotate the mast, which should be supported only near its ends. Supporting it near its ends on sawhorses will prevent the diamond spreaders and backstay crane from interfering when you try to roll the mast over.

Installing the standing rigging — Several feet down from the top of the mast is the place where the jib and spinnaker halyards enter the mast through sheaves, usually called the "hounds." Older masts used external "tangs" to attach stays here. All masts made since about 1971, however, contain a heavy stainless steel pin that runs all the way through the mast from one side to the other (see Figure 12). This arrangement very effectively achieves its purpose of minimizing windage. Unfortunately, it can also make rigging installation tedious in the extreme!

Your objective is to insert the pin through loops in the ends of all standing rigging (except for the backstay), having first inserted each loop inside the mast. Notice that one end of the pin is secured with a nut. When you remove it, you may find the pin runs through an aluminum sleeve that you can punch out with a screwdriver. With the sleeve out, you can see a weldment inside the mast with its own hole for the pin. Running the forestay between the halves of this weldment and attaching it to the pin will be fairly easy. But attaching the main shrouds, diamond stays, and trapeze wires on each side of this structure may not.

Fortunately there’s a trick. While aligning three wire loops on each side of the weldment may be difficult, only two should be fairly straightforward, so why not (1) make the diamond stays and trapeze out of one long piece of wire with a loop nicopressed near the middle, or (2) nicopress the trapeze wire to the main shroud outside the mast. Just be sure that all the loops are big enough to fit the pin/sleeve!

Now you’re ready for assembly by inserting the pin back into the mast, passing through all the wire loops along the way. To do it from starboard to port with the mast lying on its starboard side, insert the starboard shroud in the triangular hole below the pin hole until it’s visible through the pin hole from the port side. Similarly, insert the diamond and trapeze wires (remembering that the diamond should emerge through the triangular hole forward of the shroud, and the trapeze should emerge aft of it).

Now, skewer these loops with a screwdriver from the port side. Then push the pin/sleeve in from the starboard side, displacing the screwdriver, until they reach the weldment in the center of the mast. (Since you may lose track of the loops during this process, pull hard on the starboard wires when you’re done to be sure you’ve captured them all.)

Next, install the forestay between the two parts of the weldment, and then the portside rigging using the same technique. These should be much easier.

Finally, replace the nut and tighten it against the sleeve. Since you want it never to come undone by accident, use Loctite or peen it in place when you’re done.

Completing the diamonds — You can attach the bottom of the diamonds (1) to a pin through the mast similar to the one just discussed, (2) to tangs mounted low on the mast for this purpose, or (3) to a "magic box" that will make them adjustable (in which case you’re on your own).

With either of the first two options, install a turnbuckle on each diamond and unscrew it all the way. Then, run each diamond through the spinnaker pole ring to the bottom tang. Next, remove the spreader end fittings and pull one diamond out to the end of its spreader. If the turnbuckle is properly tightened, this should bend the mast sideways, but you should experience no difficulty until you try to repeat the process on the other side. Brace your foot against the mast and slide the second diamond along the spreader and over the end, crossbow style. Success? If yes, the turnbuckles are too loose; tighten them and try again!

When you’ve got both sides in place with the tightest possible tension, check for side-to-side mast bend by sighting up the mainsail groove. Tighten the looser turnbuckle until the groove is exactly straight.

Rigging a preventer — On a Tempest, a preventer is a light wire, line, or shock cord run between the diamond spreader tips and the main shrouds (see Figure 4, page 4). Its purposes are 1) to keep the spinnaker halyard from catching behind the spreader during takedowns (not a problem if your boat has a spinnaker launcher), 2) to keep the trapeze wire from wrapping around the main shrouds, and 3) to restrain the middle of the mast from flexing forward when the boat hits a wave, dumping power. (2) and 3) are not problems if you use swept-back spreaders attached to the shrouds.)

Many people use a shock cord because they’re not sure of the proper length, but this can only accomplish the first two purposes mentioned. Light nylon "parachute cord" with a finished length of 11 inches is less elastic and has less windage. Although wire is theoretically best, nobody uses it.

To minimize windage, you’d want to crimp the shock cord or nicopress the wire. Maybe this is really why people just use line: they merely tie it in place with a clove hitch around the spreader end fitting in front, and then tightly around the main shroud at equal height.

Completing the shrouds and trapeze wires — Proper shroud length is listed in Appendix E. If you use turnbuckles, you’ll need to measure only approximate length before cutting the shrouds. To be certain, you can extend the turnbuckles and then err slightly on the long side.

Proper trapeze length also is listed in Appendix E. You must choose between continuous and independent (see Figure 13) trapeze arrangements. If a factory-rigged Mader boat is available, you can copy it exactly. Note, however, the variation shown in Figure 13 that can prevent your sleeves from catching in the block.

Installing halyards — Masts are usually delivered with lead lines installed. You can simply tape your halyards to them and—carefully, so the tape won’t let go—pull them through.

When you’re starting from scratch and no leader is available, however, you’ll have to use a plumber’s "snake" to thread the main halyard. Or, if other halyards are already in place, just tie the new halyard to one of them and pull it through.

At all costs, prevent the halyards from twisting around one another. Take the plug out of the base of the mast and look up inside it if you’re not sure. Also, the main halyard must run aft of the internal weldment at the hounds, so it won’t groove the weldment in use and eventually jam.

As soon as you’ve nicopressed the bottom loop in each main and jib halyard wire, tie on the halyard tails or splice them on to minimize the tendency to jam in the sheaves. For minimum drag/weight, use ¼-inch double braided line with the core removed, and eye splice it back through itself. 

Adjust the height of main halyard’s hook/stop on the mast so that the shackle lies just below the masthead black band when the halyard is hoisted. Don’t forget a stopper knot.

Topping lift — It’s possible to mount the topping lift externally: just run a wire with a hook on the end of it through a block screwed to the forward side of the mast up near the spreaders, then back down to a line you can cleat near the partner. However, as this arrangement creates more windage and crew confusion than an internal one, most boats have exit blocks at this location. The topping lift enters the mast here, then exits via a sheave near the heel of the mast. A bullet block on an eyestrap screwed into the plug in the heel will work perfectly well if all other sheaves are already being used.

Backstay — The backstay is simply a light wire attached to a backstay "crane" at the top of the mast, which keeps the backstay from fouling the leach of the mainsail when you tack. The bottom of the backstay should end in a bullet block, through which runs a 2:1 control line leading forward to cleats on the aft deck near the cockpit. While you can use a shorter control line, a 17 ft. length will enable you to secure the tiller when the boat is moored.

THE BOOM

The vang and mainsheet normally attach to slides that can be tightened in place along a track on the underside of the boom. Mount these slides with the wingnuts forward so the spinnaker sheet won’t catch on them when it runs under the boom. The vang slide should be about 60cm from the forward end of the boom. The boom needs little other preparation, except that a rubber doorstop screwed into the aft end will keep it from chewing up the deck when you drop the mainsail.

PREPARING NEW SAILS

THE MAINSAIL

Telltales — You don’t need many telltales on the main, and you shouldn’t spend much time watching them, because the "backstay rule" (see page 22) should tell you what you need to know about trim. As shown in Figure 15, however, 125mm telltales about halfway back along the top batten can tell you when flow is beginning to detach from the leeward side of the sail, and ten-inch telltales flying from the top two batten pockets can guide you in mainsheet and vang trim on reaches.

Batten Pockets — Even with the backstay crane, the backstay on many boats can come in contact with the roach of the mainsail. As the top two batten pockets must slide inside it during a tack, any protruding seam or pocket opening can cause a hangup, so you don’t want a "butt-joint" batten opening on the top two pockets. Instead, you want an overlapping opening, as shown in Figure 15.

Windows — The large mainsail and jib windows should be roughly at horizon level when the boat is sailing upwind in heavy air.

The size and position of the small window on the mainsail, however, are more critical. In heavy air, the crew must be able to see the spreader through the upper forward corner of this window while out on the trapeze. In light air, the skipper must be able to see it through the lower aft corner. 

A good window will be about 160mm from the luff of the mainsail (less than 150mm is illegal) with its lower front corner 2200mm from the center of the tack cringle. In size, 325mm high by 275mm wide is about right.

Sail numbers and letters — The class rules call for 38cm (i.e. 15-inch) numbers with a projected space between them at least 70mm (i.e. three inches) wide, which class measurers interpret to mean a clear strip from the top of the numbers to the bottom. Three inches is safe. The mainsail letters and numbers are usually placed midway between the middle two battens, and the class insignia is centered over them halfway to the head of the sail.

THE JIB

The jib leech on a Tempest is difficult to make so that it won’t flutter. Many sailors prefer a "hot-knifed" leech rather than a leech tape. If excessive flutter proves to be a problem, the sailmaker should be willing to install a leech line.

Telltales should be about 125mm. Attach them where they won’t snag on any nearby seams. Mount a set in the window panel, another set two panels up, and a third set two panels farther up.

Double pairs in the two lower positions will be visible to the skipper under most conditions, and provide for more certain reading.

The spreader-to-leech distance is the key to jib trim. This is visible only through the mainsail window under most conditions, however, and can be extremely difficult to read, especially in flat light. You can solve this depth-perception problem by making five dissimilar black marks on the jib leech at two-inch intervals, with the bottom one where the jib touches the spreader (see page 22).

Common practice is to use a one-piece jib sheet with a figure-eight knot through the sail at each end. Hence, the jib clew cringle should be large enough for both ends of a 7/16 inch one-piece sheet to pass through, but small enough to hold the knots.

Most sailmakers cut the jib leech shorter than the class rules permit so the jib can be trimmed with the usual mast rake. But in the process, some are not careful to avoid making the jib foot round too deep! It must not extend more than 140mm below the line L1–C1 specified in the class rules. There are other tolerances to meet, too.

Unless one sailmaker made all your jibs, their luffs probably won’t be equally long. When there’s a significant difference between the longest and shortest, your jib halyard may not be adjustable enough to fit them all. Fix this by shortening the halyard a few inches and then attaching a permanent wire pennant to the head of all your jibs. The pennant length plus jib luff should, of course, be the same for each.