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by Bernd Kohler - The Netherlands ikarus342000.com

Part One - Part Two

In the previous article I was outlined the theory of the rig. Here some ideas how the rig can be made and how it is handled.

Handling

See drawing below. Lets presume the sail is furled. Open the furler, clew and peak control jammers.

Pull at the same time at the clew control and peak control rope. The sail will unfurl. Set the clew taut and fix the rope with the jammer. Now set the upper sail with the peak control to the necessary tension and close the jammer. Tension the furler rope a bit and close the jammer. Depending on you use a stabilized boom or not, loosen the topping lift.

Set the main sheet as required for the course, wind direction and wind force. Set the twist in the sail as required by rotating the mast. In very light wind try to catch the upper wind better by reducing the twist in the sail. In situations with a lot of wind you can spill the wind in the top by rotating the mast a bit more in the face of the wind.

Set the main sheet as required for the course, wind direction and wind force. Set the twist in the sail as required by rotating the mast. In very light wind try to catch the upper wind better by reducing the twist in the sail. In situations with a lot of wind you can spill the wind in the top by rotating the mast a bit more in the face of the wind.

Furling the sail or reducing sail area - set the topping lift if applicable. Loosen the peak jammer, loosen the clew jammer and pull on the furling rope to reduce sail as required or complete. Hold the peak and clew rope at tension to roll up the sail as small as possible. You can furl reef the sail in any wind direction with a bit of experience. When setting the sail for the first time, connect the tack directly to the furler drum. Connect the head directly to the swivel. The bolt rope has to be Dyneema rope formed into eyes at the head and tack.

Set the sail with the halyard rope. Again, I prefer Dyneema. Set as taut as you can. When you have a halyard winch use these. But setting taut by hand is normally sufficient, depends of course of the size of the main. To set the luff taut use the turnbuckle on the furler. This is more efficient as any winch.

Types of Wishbone Gaff Rigs

The picture below shows the wishbone gaff with rotating mast. We have used a different set up. We used a hinge in the wishbone gaff and controlled the gaff over the main stays on. The control ropes are then going from the wishbone gaff to a small swivel block on the stay to the deck. Again, a small block leads the rope to a jammer near the cockpit.

Here isthe rig on an ECO7.5. Mind the blocks for the wishbone control are to low. But this was a first set up and is corrected by now. The picture gives a good impression how the rig looks.

Realisation of the Rig

I can give here only some general ideas how to build the rig.

When you start use Aluminum tubes which you can buy almost everywhere. For a main sail up to about 30m² the dimensions I give in part 1 are valid. Slide the upper part in the lower tube. Use aircraft quality Monel rivets with a diameter of 8 mm. Use also Epoxy glue. Use a AL. Rod which is rounded on the bottom. Glue with plywood disks in the mast base. For the wishbone we use stainless steel tubes (start with a diameter of 30 mm). Make a pattern for the shape of the wishbone legs. Bending stainless steel is not difficult, but fill with dry sand before applying heat for bending. A blacksmith who can help you would be handy. The ends can be hammered flat as shown. Again, heat till red.

The mast top can be made from 3mm stainless steel sheet. The shape shown is only an idea. Same for mast base. Do not worry that the goose neck fitting is behind the "turning point" of the sail. The opposite in this way the sail is more flat on the wind where you need a flat sail and more full before the wind. When you would like to refit your boat and have already the normal mast, use the second system. This is what we where using on our PELICAN catamaran. The sail is under high load in this rig. So, a radial cut sail will be the best. Chamber for multi hull main sail 4 or 5 % of the corde of the sail. This will give the best performance. Do not skimp here. The sail will be a bit expensive. But when you need or wand a main sail with the same performance as this rig with all his (expensive) battens, batten cars, reefing blocks etc. you are better of with the wishbone gaff rig.

Copyright © 2013. All Rights Reserved, by B. Kohler.

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