clew

Unique Aramid frame panel lay out

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Tested in heavy shorebreaks!

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Overlapping panel reinforcements at clew and tack

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Overlapping batten pockets

The battenpockets are made by overlapping the panel below and above to both sides of the batten pocket rather than joining the panels with a single seam in the middle and slapping the batten pocket on top. This gives a double seam and a fully symmetrical profile. Both seams are double stitched.

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Double seams

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Double ring clew

Use both rings for the average position.
This is also stronger for if there is a heavy shorebreak.
The top ring can be used for light wind+taller sailors,
the lower ring for high wind+short sailors.

 

A BIT OF SAIL THEORY

There are a few basic guidelines for sails (or any foil really):

-a sail converts wind into power by bending the airflow. So the more bend, the more power.

-The lee side of a foil delivers 2/3rd of the power. So important to keep the lee side smooth.

-The first 1/3rd of a foil delivers 2/3rd of the power. Or better said: mast length is more important than boomlength or surface.

Wave sails can get shape either through batten rotation or seam shaping.

-Batten rotation:
Pro: Depowering and less drag down the line
Contra: smaller windrange

Batten rotation allows the sail to become flat without wind so the sail can depower when needed. But, as battens them selves want to stay straight, such sails require more wind to power up. Also the stability of the sail then relies only on batten profiling, with a reduced top end control as a result. When set full, a rotational sail can be hard to rotate and become even more unstable, also the mast pocket does not line up with the sail well anymore, losing efficiency.

-Seam shaping:
Pro: big wind range
Contra: depowering and drag down the line

Seam shape pre-bends the battens and has more low end power as the wind does not need to bend the battens to get shape. Also the stability does not only rely on the batten profile but also by the shape of the sail itself with a higher top end as a result. As the shape is always there, the battens are derotated all the time, the sail does not depower well and drags more when going down the line.  When set flatter, a sail with only seam shaping has the batten tips not lining up with the mast pocket, creating a bump on the leeward side creating a loss of power. Sail rotation is also harder and power delivery more jerky.

Witchcraft sails are designed to use a combination of both seam shaping and batten rotation to create the best of both worlds:

-There is good low end power as the battens are halfway pre-bent.

-As the battens them selves want to become straight, the sail still depowers very well.

-As the profile stability is held by both seam shaping and batten profiling there is a very good top end control, even when set full.

-As the mast pocket lines up with the sail at all times, there is increased efficiency and soft batten rotation throughout the settings range.

-The higher aspect ratio also makes the sail more efficient for its surface. Therefore you can rig a smaller and lighter sail with a shorter boom giving more manoeuvrability and liberty to move the sail more and faster in turns.

THE PROFILE DEPTH MORPHS THROUGH THE RANGE, THE SMALLER THE SIZE THE LESS SEAM SHAPE AND THE MORE BATTEN ROTATION.

In this way a smaller biggest sail can be chosen. Not only does being able to use a smaller sail save weight but also gives you a stronger rig. The smaller the sail the less loading a wave can put on the sail and a smaller sail exerts less leverage on your mast and boom, it’s a win win situation.
In the clew there are 2 eyelets to cater better for taller or shorter sailors or to finetune the amount of leach twist. Using both eyelets (see rigging manual) will give the average setting.

THE CONSTRUCTION IS ABOUT THE BEST POSSIBLE

We are experienced sail makers with many years of repairing sails. There is lots of Kevlar X-ply and all panels are layed out into the forcelines, similar to the new membrane sails but less cost intensive, much more puncture resistant and easier to repair if necessary. The batten pockets are made with overlapping panels, creating a symmetrical sail shape and giving a double seam for extra strength without costing extra weight.

All important seams are double and running along the stress lines and are not put across stress lines for optical reasons. Like this the seams actually work as tendons. Also at the clew and tack, the joining panels widen again to overlap and create the reinforcement by the panels itself rather than needing all reinforcements being stuck on.

We chose our own seam tape with very strong and durable adhesion and does not suffer from contact with water or UV light.

WE AVOIDED THE USE OF THE SUPER THIN SCRIM

Our philosophy is that a WAVE sail should handle being washed frequently by waves up to 2m easily and the occasional bigger wave as well. It should not break but neither should it lose its crispness. But we saw the thinner scrims getting stretched quite quickly after just a few weeks in small to medium sized waves. So the scrims we use are medium thick and use stronger types of fibres such as Pentex and Kevlar.