Optimist Tuning Tips

 

(1) Parts of the Optimist

 

Step One:  Set you mast rake according to your weight and the sailing conditions -this is a highly personal measurement which effects power and pointing. The following table should be used as a starting point for your rake. From that starting point you should adjust the rake to suit your personal sailing style (are you a "footer" or a "pointer"?), the wind conditions you will be sailing in, the sea conditions and your spars (are they stiff or bendy?).

Generally, your rake should be adjusted so that the boom is parallel with the water when sheeted for optimum upwind sailing.

Weight (kgs) Mast Rake (mm)
Under 30 2768-2794
30-35 2794-2819
35-40 2819-2845
40-45 2845-2858
45-50 2858-2870
50-55 2870-2883
Over 55 2896-2908
 
(2) Parts of the Sail

 

(3a) Head
(3b) Tack

 

Tips on tying on the sail.
  1. Tie the Head of the sail first.  Start by lining up the top sail grommet and the top mast eye.  Tie around the entire mast passing through the top sail grommet and the top eye strap. Next, tie from the top sail grommet through the lower eye strap. This tie should not be tight, it should only prevent the first tie slipping over the top of the mast. (see illustration (3a))
  2. Tie the Tack next. The tack uses two corner ties, one to secure it to the mast and one to secure it to the boom. (see illustration (3b))
  3. Tie the Clew last. A common mistake is tying the clew directly to the lip on the end of the boom, this is incorrect. The clew should be tied around the boom so that it slides freely.
  4. Now that the corners are ready, use the Sail Ties  to finish tying the sail. The ties along the mast should be tight, with no more than 3mm. between the sail and the mast. The ties along the boom should have a space of about 6mm. between the sail and the boom.
Rig your boom bridle.
  1. Locate the two Boom Bridle Buttons on the top side of the boom, each is about midway to center on either end. Attach the Boom Bridle  to the boom by tying around the boom on the outside of each button. (see illustration (4))
(4) Outhaul and Bridle

Rig your control lines.

Locate the Boom Vang Button near the jaw end of the boom. Use the Vang line to tie around the boom so that the button prevents the line from sliding toward the mast. Then tread the line through the vang cleat on the mast , from the bottom to the top.

Tuning Tip - The vang controls the luff tension upwind and leech tension off the wind.


>5 knots :Use the Mainsheet to trim for your upwind boom position, then cleat the vang at that spot. If the wind is puffy, trim for the median wind speed but, leave a small slack in the vang. This will give you added leach control upwind

8 to 12 knots : Trim until the boom is centerline and 5 to 8 inches off the transom, then cleat the vang. In puffy conditions, trim for the median wind speed or slightly less.

15+ knots : Trim until the boom is 0-3 inches from the transom, then cleat the vang. If the leach is stalling, ease the vang slightly or loosen the clue tie.

 

Now rig your Outhaul. Tie a stopper knot in the end of the line. From the back of the boom, thread the line through the hole in the lip of the boom end, through the sail grommet, then back out the hole in the boom end. Now run the line through the cleat located on the side of the boom.

Tuning Tip- In medium air, the outhaul should be trimmed with pronounced scallops along the foot. The clue should be 3-6 cm from the end of the boom. In heavy air the outhaul should be tightened so that the scallops are removed. However, it should never be so tight that a hard crease in the foot is induced. In light air it should be eased to a maximum of about 7 or 8 cm from the end of boom.

 

The next sail control is the Sprit Halyard. Locate the Sprit Halyard Block on the front side of the mast. Run the Upper Sprit Line through it and tie a small bowline (loop) in one end. To the other end, tie the Micro Block. Now locate the Lower Sprit Line and tie one end to the bridge of the Sprit Halyard Cleat. Next, run the free end of the lower sprit line through the Micro block and through the sprit halyard cleat. (see illustration (6))

Tuning Tip- When rigging, slight wrinkles should appear from the sail's peak to the tack. In light wind these wrinkles should be very small, in heavy wind the sprit should be tightened so that the wrinkles become pronounced. In any wind speed, the sail should be perfectly smooth at the median or predominant wind speed on any leg of the course. As a result, slight wrinkles will sometimes appear from the top of the mast to the clue in puffs and from the peak to the tack in lulls. In medium and strong winds, especially with light sailors, err to the side of wrinkles from the top of the mast to the clue, as this will open the leach, rather than stall it. Generally, it is better to lose pointing and gain speed by opening the leach rather than losing both pointing and speed by stalling the leach.

(5) Boom Vang
(6)
Sprit Halyard
 
Rig the Main Sheet.

Start by securing the Boom Block to the boom bridle with the trigger snap. The trigger snap is your quick release system for the sail.

Tie one end of the Main Sheet  to the boom block becket (the white nylon part). Run the free end through the small hull block from back to front, through the boom block from front to back and through the large ratchet block. (see illustration (7)) Make sure that the ratchet block "clicks" when the main sheet is tightened and locks when the main sheet is released. If you prefer to turn off the ratchet, you can do so by adjusting the slide on the side of the block.

Tuning Tip- The Mainsheet controls boom position, it is a balance between pointing and speed. Upwind, the sail should be trimmed to the leeward comer of the transom for most conditions, further in for heavy air, further out for light. It is usually better to give up maximum pointing for increased speed.

Finally, secure the Mast Tie Down! This is the most important line on the boat.  To secure the Mast Tie Down, tie around the mast and over the vang cleat. It is very important that this line is always tied, and tied tightly. (see illustration (8)) Failure to secure this line will result in a dismasting during capsize and can seriously damage your Optimist.
(7) Main Sheet
(8) Mast Tie Down

On the water adjustments

Luff Telltales- In light wind, out of tacks or while footing for speed, steer so that the luff telltales are flying straight back. In medium wind with flat water or light chop, steer so that the windward telltale is partially stalled, and the leeward telltale is flying straight back. In heavy wind (when you can no longer hike the boat perfectly flat), steer so that the windward and leeward telltales are somewhat stalled. A luff should only be carried when feathering in very heavy winds. Before carrying a luff, you should consider raising your centerboard slightly to depower the boat.

Leach Telltales- Because of the limited control the vang offers on an Optimist, the leach telltale is mostly an indicator of mainsheet trim. Generally, it should be steaming straight back with the curvature of the leach. If it is stalling to windward, you are under trimmed. (The luff telltales will almost always be a better indicator of this) If the leach telltale is stalled far to leeward, you are either carrying too much vang or are over trimmed, either way the leach is stalled.

Boom Preventer - It is important to have a preventer attached to the jaws of your boom, which when slipped over a stop on the front of the mast will limit the booms ability to slide downward when heavy vang tension is applied
which will have a large effect on its shape. Not only will the preventer keep the bottom of the mainsail from being pulled past the band, it will also properly control the tension of the luff of the sail in conjunction with the vang and sprit. In medium winds the luff should have "neutral" tension under pressure, no horizontal wrinkles or vertical wrinkles. In light winds, one or two twists should be added to produce very slight scallops under pressure. In heavy winds, twists should be let off to produce a vertical wrinkle in the luff, however, that wrinkle should disappear under pressure.
 As the wind increases and in heavier chop, it is best to increase the tension on your luff by allowing the boom to slide down the mast slightly until the luff is completely smooth with no wrinkles whatsoever. A method to facilitate properly adjusting the tension of the luff of your Optimist main, is to take twists or turns in your preventer lines before slipping it over the stop on the front of the mast. Set the length of your preventer so that there are no turns when the luff is at its tightest position (boom is at its lowest) and then take progressive turns in the preventer to reduce the tension in your luff for lighter winds. Poor pointing can often be attributed to luff tension being too tight. If pointing is a problem, check to be sure that you have slight wrinkles off each luff grommet.  On the other hand, if you find you are pointing really high and the boat seems to stall easily, then perhaps your luff tension is too loose and you need to remove a twist or two on your preventer and allow the boom to slide down slightly thereby tightening the luff.

Centreboard Position

Upwind the centreboard is usually kept all the way down, flush against the top of the case. However skippers under 35kg may find that in heavier winds, raising the board 75-200mm can help them sail the boat flatter and with more neutral helm. Actually helm balance is the key, moreso than the actual measurement of how high the board is above the top of the case.

As the mast is raked further aft in heavy air, the board should be progressively be raised so the boat is sailed with a very light helm.

For all sailors, it is best to move the centreboard right forward in the case in light to medium winds, and to slide it right aft in heavy winds. In medium winds, position it in the middle of the case.

Broad reaching, the board should be nearly 500mm above the case.

Downwind be sure to pull your board up to reduce wetted surface area and more important, balance the helm. When sailing dead downwind, with the boat heeled well to weather, the board should be pulled up so that there is barely an inch sticking out below the bottom of the boat. On a beam reach, the board should be pulled up so that the top of the board is nearly 300mm above the top of the centreboard case.

Tip:  use a waterproof marker to record these positions on your centreboard with  so you will be able to consistently use the same board settings during the race.