SAIL Magazine's Sailing Tips
by Michael Tamulaites,
The Jib-trim Series, Part I
The first elements of sailing are raising and trimming your sails. If you're a hardcore racer who thinks you've got this step licked, I'll see you on the race course, but for most of us there is always something to learn.
I'm going to start explaining sail trim where it begins, the jib. Many sailors try to trim the main and jib as separate entities. Aerodynamicists know, however, that for best overall sail trim you have to start with the jib and then go to the main. The airflow relationship between the two is key. In order to trim the jib correctly it has to be raised correctly.
Step 1-- halyard tension: There are two jib/forestay combinations on most boats--jib hanks on a bare forestay, or a luff tape/boltrope that slides into a headstay foil through which the forestay leads.
Hank-on system: Once your jib is hanked on to the forestay and you're in open water, raise the halyard. Tighten the halyard until there are vertical wrinkles along the luff of the jib, right behind the forestay. While sailing on a close-hauled course, with the jib trimmed for upwind sailing, ease the halyard (make sure it has at least two wraps on the halyard winch before uncleating) until the vertical wrinkles just disappear. You've eased the halyard too much if the sail begins to "scallop" between the jib hanks. If you've eased to much halyard, ease the jib sheet a couple of feet or more and ask the helmsperson to sail close enough to the wind to luff the front half of the jib and then re-tension the halyard with the halyard winch.
Headfoil system: Again, start by pulling the halyard up until vertical wrinkles appear and sail away on a close-hauled course. Ease the halyard until the vertical wrinkles just disappear. If horizontal wrinkles appear behind the forestay, the halyard has been eased too much so you need to ease the jib sheet, have the helmsperson head up and re-tension the halyard and start again.
The Jib-trim Series, Part II
Last week I explained how to properly tension the jib halyard with either hank-on or headfoil jibs. This week I'll explain why we start with the halyard tight and then ease it and if we have to adjust the halyard while sailing, why it's better to pull the halyard back up all the way with the front half of the jib luffing and then ease it back down to proper tension.
When working with any load, it's best to make the load as light as possible. The least amount of load on the halyard in any given breeze is when the sail is luffing. So when you first raise the sail is the best time to tension the halyard to its maximum height which occurs when vertical wrinkles appear behind the headstay. The maximum load on the luff of the jib occurs when you are sailing close-hauled. In order to decrease this load to adjust the halyard it's best to ease the sheet, have the helmsperson head toward the wind, and then with the front of the sail luffing, tension the halyard.
The second reason you over-tension the halyard then ease it down rather than set the sail with too little halyard tension than try to raise it, is friction. If when you are sailing on a close-hauled course in a decent breeze and you see horizontal wrinkles appearing in the sail behind the forestay, you know the halyard needs to be tensioned. If at this point, you wrap the halyard around a winch and crank merrily away, you will only tension the top portion of the sail. The wind pressure on the sail, combined with friction between the sail and the headstay makes it nearly impossible to evenly tension the whole luff without putting undue stress on the top of the sail and the winch. What you end up with is luff in the top of the sail being way too tight while the luff near the bottom of the sail is still to loose. The sail with this sort of luff tension is not pretty and it certainly is not fast.
If you don't want to ease the sail to tension the halyard, their are three solutions. In light winds, under 10 knots, try to simply raise the halyard. If the horizontal wrinkles disappear along the luff evenly, not just the top ones first, you're all set. Also in light winds you can overtension the halyard until there are vertical wrinkles, then ease it. Otherwise do what racing sailors do, tack. Set the winch up with at least three wraps, and be ready to tension the halyard. As you tack, and while the fib is going from one side to the other, it's luffing, so cranking the halyard up is easy. On the new tack, you can ease the halyard if necessary, to properly tension the luff.
When you ease off from a close-hauled course to a reach, there is less wind pressure on the sail so vertical wrinkles may appear again along the luff. Ease the halyard until the wrinkles just disappear. Remember, that before you head back up to a close-hauled course, over-tension the halyard so that you can ease it to proper tension after the jib is trimmed in.
The Jib-Trim Series, Part III
Now that you know how and why you adjust your jib halyard, it's time to learn the same for jib leads.
A sailboat under sail depends on its sails for power--that much is obvious. To give your boat as much power as possible in light to medium winds, say 0 to 12 knots, or to decrease power above 12 knots, you need to use the jib leads. They are your throttle as far as the jib is considered. Of course, as the wind picks up you may change to a smaller headsail, but you'll need to know how to control the power for that sail as well.
Start with telltales. They are the pieces of nylon, cassette tape, or, traditionally, yarn, near the luff of the jib. The best location for telltales are three sets of two (one on each side of the sail, starboard just above port so that you know which one is wiggling) located one-quarter, one-half, and three-quarters of the way down the luff of the sail from the head to the tack, and about two feet behind the forestay. With telltales in place and while sailing on a close-hauled course, it's easy to know where the jib leads need to be.
For maximum power you want both the starboard and port telltales in each set streaming toward the back of the boat, aft. If while sailing upwind, they are streaming back, your jib leads are in the right position, so have a nice sail.
If they're not streaming, here's the test. While sailing upwind, ask the helmsperson to head closer to the wind than close-hauled. As the inside telltales ( the starboard telltales when on starboard tack) start to lift, flutter upwards, notice which ones lift first. If the top telltales lift first, move the jiblead forward a hole or two on the track and try again. If the lower telltales lift first, move the jiblead aft a couple of holes. When all inside telltales lift at the same time, your jiblead is correct.
Once the jibleads are in the right position, meaning all the telltales streaming aft, and the jib halyard is correctly tensioned, your jib is set for maximum power while sailing upwind. Next week, I'll explain how to depower the jib and change jiblead postion while racing.
The Jib-Trim Series, Part IV
As the wind increases, you will want to depower your sailplan for the most comfortable, and in general, the most efficient sailing. Without changing your jib, here's how it can be depowered.
Physics I: When the jib leads are in the correct position, all telltales are streaming aft, the sail is at its most powerful--it's taking as much of the wind's pressure as possible and turning it into forward driving g force. The fastest way to depower your jib while maintaining your course is to ease the jib sheet completely. The sail will blow out so that it is luffing, much like a flag blowing in the wind. The pressure is released, the jib is providing almost zero power. As you start to trim the jib sheet you will see that the sail looks full first at the clew, then as you trim it in, the sail fills from the clew forward with the leading edge of the sail, the luff, the last part to stop luffing. Easing the jib sheet to depower is effective, but it is not efficient.
Physics II: The wind pushes on the jib which pushes the boat over, makes it heel. Imagine a model sailboat sitting in a bathtub. If you push on the top of the mast, the mast will act as a lever arm and heel the boat over a certain amount. Now if you push on the middle of the mast so that the lever arm is much shorter, with exactly the same pressure, the boat will heel much less. So another way to depower your jib is to cut off the top half. That way there will be less pressure (zero)on the top of the mast from the jib. Cutting the top of your jib off to depower is effective, but is not only inefficient, it's expensive.
The Jib-Trim Series, Part V
There are predominantly two jib-lead systems. Most racing boats and a growing number of cruiser/racers and even cruising boats, are equipped with a nearly friction-free jib lead (whether using hard nylon inserts or roller-bearings) running on a matching track with a block-and-tackle or winch system that allows you to adjust the jib lead under load. These systems are commonly called adjustable jib leads, but of course, most jib leads are adjustable, just not as easily. This is the fastest and most conveient method of moving jib leads.
It's also dramatically more expensive than the traditional system that incorportates a jib lead with a piston, either spring-activated or screwed into place, used on a T-track with holes to receive the piston and lock the lead in place, evenly spaced along its length. Each systm has its advantages and disadvantages. Choosing is a personal preference, but here are some thoughts:
The adjustable system allows you to easily move the jib leads while racing for the perfect trim, or for a sail change.
Four boats with roller-reefing systems, adjustable jib leads allow you to easily move the leads as the sail is rolled or unrolled to maintain a good sailshape.
Adjustable leads are relatively expensive and if the control line breaks, the leads will shoot aft. Most companies, however, have stoppers that can be slid behind the lead once it is sent to prevent the lead from shooting aft if the line breaks. Adjustable leads require a bit more maintenance in that there are more parts involved.
Traditional jib leads are less-expensive, but much less convenient. The load must be taken off the lead in order for it to be moved.
Long-haul cruisers might like the security of knowing that the lead will stay in place with no control lines to break.
Traditonal leads also require less
maintenance and help to minimize on-deck equipment that could trip you.
If your boat is equipped with "non-adjustable" T-track jib leads, there are a number of tricks to moving the lead, without luffing the sail. I'll tell you how in next week's Sailing Tips.
The Jib-Trim Series, Part VI
There are a number of ways to move T-track-style jib leads. In light winds, say 5 knots or less, the load on the sheet is minimal, so you can just move the lead. As the wind increases and the load gets to the point where it's not easy to move the lead (remember, the bigger the boat, the faster the load will increase) you can ease the jibsheet until the sail luffs or working in concert with the helmsperson you can ease the sheet some while the boat is turned closer to the wind to make the sail luff. Either way, with the sail luffing there is no load on the jib lead so you can move it. This method should not be used in winds much above five or six knots or boats much over 35 feet, because when the sail is luffing, the jibsheet is thrashing around. The thrashing sheet not only makes it hard to move the jiblead, the sheet may hit you which could be dangerous.
With the wind increasing beyond five or six knots or if you're sailing a bigger boat, safety is the primary concern when moving the jib lead, not speed--but there are some methods that provide both. If you're on starboard tack, and the jib lead is in the wrong place, the simplest and safest way to adjust the jib lead is to tack. This method is also best if you are racing around the buoys because you can wait to adjust the jib lead until your tactics say you should tack. Before tacking, move the new jiblead, in this case the one on the starboard side of the boat, to where you think it should be--one or two holes forward or aft of the jiblead in use on the port side of the boat. Then, after tacking, take a look at the jib. If you like the way it looks, the jiblead is in the right place. Now move the jiblead on the port side of the boat to the same position as the one in use on the starboard side and then tack back to starboard tack if that sends you in the direction you want to go.
If you don't want to tack, and can move an extra jiblead to the same track as the jiblead in use, whether forward of the working jiblead or aft, you can safely change the jiblead. Tie an appropriately-sized extra line to the jib's clew and lead it through the extra jiblead. Make sure that the extra jiblead is in a position that will allow you to move the working jiblead to where you want it. Then lead the extra line to a turning block and then to an extra winch, or just to the winch. If you don't have an extra piece of line you can use the bitter end, the tail, of the working jibsheet. If a winch is not available, lead it to an appropriately strong cleat and cleat it off. If the extra line is on a winch, trim it so that the working sheet goes slack. If the extra line is on a cleat, slowly ease the working sheet until it is slack. With the working sheet slack you can safely move the jiblead to where you want it, and then retention the sheet. Look at the jib and if you like the way it looks untie the extra line you were using so that if you want to tack it won't get in the way.
There are other ways to move T-track style jibleads, but these two methods work well and are safe. Remember, that a jiblead under load looks passive, but as the wind increases, the strain on the line increases. Always be careful when working with and around sheets under load.
In what will probably be the last piece on trimming the jib, next week I'll address various forms of changing the jiblead for proper sail trim when reaching and running downwind.
The Jib-Trim series, Part VII
When reaching, trim the jib nearly as you would when sailing close-hauled. You want all of the telltales streaming aft. But when you ease the jibsheet for a reaching course, you are effectively changing the location of the jiblead. It works like this. When the jib is trimmed in for closehauled sailing, the jibsheet pulls aft on the sail and down on the sail. By easing the jibsheet, a lot of the downward force is removed and the wind pressure on the sail causes the clew to rise and the leech of the sail to open, to become less tight. Without easing the jibsheet, moving the jiblead aft has a similar effect because the downward force on the jibsheet is decreased.
If you don't move the jiblead while reaching, all the sets of telltales will not stream aft at the same time. So as you ease the jibsheet you need to move the jiblead forward until all of the telltales flow aft at the same time, which indicates the best jiblead position, and therefore, the best sail trim. Remember previous sailing tips on how to safely move the jiblead.
As you sail further away from the wind to a beam reach and broader, you will want to move the jiblead outboard, to the rail, if possible, so that you ease the mainsail. Moving the jiblead to the rail will help to keep open the slot between the jib and the main to help maintain proper airflow. If your boat is equipped with an aluminum toe rail with holes in it, or a steak rail with a T track mounted on the top the task is made relatively easy. If your boat doesn't have such a toe rail you would need to mount a padeye in the appropriate position.
Use a block with a snapshackle or even a regular shackle and attach it to the aluminum rail or T track a little forward of where the jiblead is located. Tie an extra piece of line at least as strong as the jibsheet to the jib's clew, run it through the block on the rail and then to spare winch. If you don't have a spare winch, you can ask the helmsperson to luff the jib by steering closer to the wind, or you can luff the jib by easing the jibsheet and then lead the extra jibsheet to the primary cockpit winch. If the wind is strong, say above 10 knots, don't luff the jib to change the leads. Either tack and then relead the original jibsheet through the block on the rail and tack back, or drop or rollerfurl the jib and lead the extra jibsheet to the primary cockpit winch. You could also lead the jibsheet through the block on the rail and then to the primary winch.
As you turn downwind, you will not be able to trim the jib according to the telltales. Basically the jib will just hang limp and useless behind the main.