When we start a project, whether it is for an Optimist or a Farr 45, the basic principles of sail making apply.

To make fast, easily-used sails is always the goal-but getting there can be easier said than done. In the end, the only way you know if you've got it right is hours of two-boat testing. Virtual tools can be helpful but are currently a long way from providing the answers.

Lets take a Hyde-dominated fleet as an example- I won't count Lasers or RS's in this!! I think Kerr 11.3 would be a good example.

Where to start?

You take a look at the boat and its stats. Then, if possible, go for a sail with the existing sails, taking plenty of photos and video. Look at wind speed and polar's to see if we are sailing the boat 'on the pace'.

Back at the loft, we digitise the sail camber (this may only confirm that the sails on the boat are rubbish, which means that any other data that has been collected is rubbish). If this info is of any use we would then compare the shapes to our standard 'moulds'(the term used by our soft ware to describe the mathematical 3D modelling).

Next, we look at data from other similar boats-looking at sail shapes and profiles and comparing the boat's resistance to heeling (stiffness). Now we are starting to get a picture of the correct shapes to use. At this stage we can also look at the very specific data collected from the boat, such as mast stiffness and bend, luff sag and so on.

Getting the luff curve right is the most important part of the design process; no matter how good the general sail design is, if the luff curve is wrong the sail can never produce its full capability. Our design software is professionally written by software producers and is commercially available- it is not written in-house by ourselves-would you buy a Photoshop or Excel-type program from a keen photographer or accountant? The software enables us to look at mast bend 'that changes mould shape', so it has the same effect as bending the mast whilst sailing. We can then asses sail shape under different conditions, and check the virtual sail against the real thing for further development purposes. In the end as long as your software is up to the job-it's the way you use it.

Our standard moulds are updated as we become convinced that we have made a step forward. To make these steps, we must trial ideas and observations. With the use of digital photos, we compare the differences between our sails and those of our competitors, assessing any weaknesses in the sails. Weaknesses both in ease of use and straight-line speed-the two are not always married. Based on this information, we then decide the direction in which to take the development.

Using all the information gathered, we compare where we think we should go with the sail shape to our library of sail shapes from other types of boats-we also discuss any other developments that have taken place that may have a bearing on any changes planned.

The material used will also have a huge bearing on the sail shape-- the firmer the cloth, the flatter the sail will be on any given mould shape.

The way the boat is sailed also affects the shape of the sails-a boat that is sailed hard on the wind will have flatter straighter-exited sails, compared to one that is sailed more freely using more twist.

Sail development tends to be a matter of iteration, with revolutions only taking place when new materials are introduced or big rule changes take place. Modern sailcloth is pretty stable stuff, which means it is getting lighter, but we as an industry are held back our size and most materials available to us are from other industries-pentex fibre was developed for car tyres for instance. As such, we get our materials second hand and late, which to some extent stifles development for the whole industry.

Although we usually only hear about development at the top end of the racing market, much development goes on in other areas. UV stabilisation in both laminates and wovens is now common place, the softening of films is adding to both lamination quality and flex life, and improvements in weaving and finishing technology along with the mixing of yarn types is adding durability to cruising fabrics. And as you will read in other areas of this site, we take the development of cruising sails as seriously as that of our racing sails.

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