It is amazing just how few of us understand the Laser Rig. This article is for all those of you who think the Laser sail is awful. Well actually I think it is remarkable just how good it really is considering the two pieces of aluminium tubing it is set on. The sail itself has to fit when the mast is straight (downwind) and bent (upwind) and look reasonable on both – try that with a Mylar sail and I’m sure you would get very frustrated.

Lets imagine the job of the sail-maker in trying to develop an all round performance sail on a two-piece Laser mast for Up Wind sailing.

So let’s assume that we have a rig that is fairly bendy. The material for the sail needs to be flexible enough to cope with the large changes of mast bend – typically a 3.8 ounce Dacron for a Laser Sail. For every upside there is a downside, and Dacron’s downside is that its flexibility means that the shape set by the sail-maker is not so stable through the wind range. The draft is easily blown ever-more backwards with increasing wind strength and age. This instability of the sail cloth is commonly thought of as a disadvantage. However, if know what you are doing with the sail controls – then you have the ability to optimise the shape of the sail for any venue and condition – probably more so than a stable sailcloth.

The Job of the Sail-maker –

The sail-maker controls the position of the draft of the sail with the position of the camber built into each of the seams. He also controls power in the sail in two ways:

1. The depth of the seams – this is simply the perceived fullness of the sail.
2. The luff curve – this is commonly miss-understood. The luff curve is the sail-makers best guess of the amount and position of the bend the mast will take up in use. Not so difficult for the Laser sail designer since most masts are in the boat at the same rake.

The sail-maker can also control the position of the camber of the sail with the position of the points of maximum depth. Typically the maximum depth in the sail is 1/3 back from the front edge, assuming the mast has assumed the bend set by the luff curve.

So let us imagine that the sail-maker has made a ‘perfect’ sail for a medium wind condition for our Laser– then let us look at the ways in which we can use the sail controls to give it best performance in both the light and strong winds.

Perfect:

So perfect means the sail is perfectly balanced with the sailor – the leach of the sail opens when a gust of wind hits the rig, and closes to almost stalling as the wind lulls. The draft of the sail is 33% back in the sail giving the sailor an easy to sail ‘luff’ (nice smooth entry) and giving the balance of power over the centre of wetted surface area giving a little weatherhelm in normal conditions. If the draft were too far back, then the sailor would experience unmanageable weather helm, and if too far forward, the sailor would experience lee helm. The sideways mast bend would normally open the leach and reduce pointing ability, but the sail-maker has added extra closure to the leach on each seam, to match the sideways bend of the mast.

Now let us look at the same sail in light winds:

In light winds we must assume that the sailor is not bending the mast sideways under the force of the wind – so each seam closure now helps hook the sail and give ever more drag (camber of the reverse side of the sail that is visible from behind the boat). The luff curve in the sail now acts as a pocket of fullness next to the mast which when sheeted out with the mainsheet makes the leach look even more hooked! Sorry but it can look really difficult! If we had spreaders we could induce a little more pre - bend and away you go! But for us we have to be a little more resourceful.

We can reduce the leach tension by using lots of kicker (vang) tension. The kicker acts in both the pushing direction into the mast as well as the pulling direction through the sail. The kicker will induce the mast to bend the same amount with less of it through tensioning the leach – therefore less leach tension.

By sheeting the main to block to block, tensioning the kicker a little and then releasing the sheet – you have a reasonable luff to steer to and a leach that is not too hooked. The sheet should be relaxed and the kicker should hold the blocks about8" apart. Luckily for us the size of the unsupported part of the sail is relatively small which reduces the hooking aspect of the sail.

Strong Winds

As the wind strength increases, the centre of effort quickly moves back in the sail which creates excessive weather helm and drag from the sail. Just push your hand into the back of the sail and watch the shape change. This can be counteracted with the use of the Cunnigham control which drags the fullness back to the front of the mast, if you do not believe me, look at the sail with Cunningham on and no kicker – gives a big wrinkle at the luff. If used too soon – this can have disastrous effects on the pointing ability. This is because the Cunningham control tensions the front of the luff of the sail, making it closer to the tension of the leach, so making the leach relatively less tight and more prone to open. Another way of looking at it would be to say that the front of the sail has pinched some of the tension from the leach.

Very Strong Winds:

Assuming the power from the sail increases with the wind – there needs to be another way to ease the tension in the leach to. Commonly the sailor would experience a shacking effect from the sail with too much fullness. You might immediately try to flatten the sail with the outhaul. First use megga Cunningham to re position the fullness to the front of the sail and use extreme kicker to again reduce the leach tension as in light winds. Use kicker alone and you will be in the soup! Without the Cunningham to pull the fullness forward, the weather helm will be uncontrollable. This is because the luff curve will have been all used up by the use of the excessive kicker, the draft will have moved even more backwards, and now Cunningham is your only saviour. A good indication of too much kicker/too little Cunningham in a Laser is that the boat wants to tack all the time – and the rudder is always heavy. I remember when I first started sailing the Laser occasionally, I would put on a what I thought was a lot of Cunningham and spend the beats fighting the boat, trying to stop it heading up into the wind. I could not believe how hard it was to sail! It was only when I sailed them full time that it became clear that the Cunningham required was extreme.

Returning to Medium Winds/Marginal Hiking Winds:

In medium winds we have bend provided by the mainsheet (aft bend) and sideways bend provided by the wind – countering the weight of the sailor.

To get the most out of your rig if you are in the marginal hiking area you probably need a sail that is very difficult to the one designed for the light and strong winds. So a sail maker makes a compromise on the ultimate performance of the marginal hiking sail so that it is made more easy to use in the strong and light winds. This is the case for the Laser Sail so it is important to remember to use the sail controls in marginal conditions to get the best out of the sail.

• Mainsheet is king

• Expensive carbon tiller

Differences between sea sailing set up and puddle set up. Generally speaking sailing on the sea has many more waves than lake sailing. Even when it is very windy – the waves on the lake never really seem to slow the boat down. I like to liken sailing on the sea to driving over a ploughed field and sailing on a lake to driving down a motorway – To drive over a ploughed field you would select 1st gear – perhaps 2nd, and you would be concentrating on accelerating the car from its almost stopped state from climbing each bump. Whereas driving on the motorway is easy to maintain top speed in 5th so long as you do not slow down too much in traffic. There is no need for 1st and 2nd – it’s the top speed that’s important.

Relating this to sail can be described by the differing set ups of a Laser.

Sea sailing - More twist and fuller luff for punching through waves:

• Cunningham – use a little from the moment the wave pattern begins to build up (12-14 knots) lots of it. (15 – above) – megga lots!
• Kicker – Light – the normal set up (8" between the blocks) medium – no kicker at all. Windy – very lots so the boom goes out rather than up.
• Outhaul – set deep – 8" between the sail and the cleat on the boom for most conditions before the use of the Cunningham.

Lake Sailing - Top speed is easy to maintain so set the boat up to pinch:

• Cunningham – used sparingly, until overpowered and the boat is unbalanced.
• Kicker – Used in the light and strong winds as normal.
• Outhaul – 6.5" from sail to cleat before the use of the Cunningham.

Remember the following:

Light winds-

Try to reduce the leach tension and loose some of the luff curve bag in the sail – kicker sheet. With the Radial Mark 6 - there is excessive fullness near the mast - so go for even more kicker tension (mind your head).

Medium/Marginal Hiking Winds-

Mainsheet is king – holds the leach most tight without bending the mast. However, the new Radial Mark 6 has the fullness too close to the mast to sail with mainsheet alone, and unless you use lots of vang, the leach has no return, as the sail is too flat at the leach. Using the vang moves the fullness back enough to give leach return and a better angle to steer with. Found this out originally at the Radial World Championships at Garda. Found myself alongside the current world champion and wondered why he had a bent boom. We were both in point mode - with my Mark 5 - I had the kicker slack, outhaul tight and no cunningham, semi hiking. When he got to the mark - he released his vang - and I realised that the boom was not bent - just that he had loads of vang tension!

Use Cunningham sparingly unless the wave pattern has built up.

Strong Winds

Use Cunnigham to pull the fullness back into position.

Kicker to reduce the tension of the leach for the same bend. In 35Knts plus use no kicker or mainsheet tension – just let the leach go!