Saturday, May 26, 2012

Dhowtful Rigging

Living in Abu Dhabi, I have seen many dhows - air-conditioned dinner-cruise boats, fishing boats and racing dhows.  The only ones with working sails are the racing dhows and there are 3 active classes in the region - 1 mast 22 ft and 43 ft and 2 mast 60 ft classes. Beautiful things to see with the billowing white sails rakishly angled.  And a very healthy antidote to the ubiquitous shopping malls and other amenities that are a mockery of Arab culture.

Even today the dhows are all made without any plans - just the watchful eye of an experienced builder, almost all of whom are from southwest India. The modern racing dhows still use wood for the hull, but aluminium or carbon fiber is used for the spars. Sails are modern materials. There is no keel although they use sandbags to lower the centre of gravity.  And race starts are not exactly ISAF Rules - before the start, all sails are down. At the start signal - traditionally flares and smoke - crews rush to raise the sails (manually) and they are off.

The sail is a lateen sail - a modern version of which is used on a Sunfish - and dhows can set an incredible amount of sail. One author gives the example of a dhow with a 20 meter mast which can have a single sail of 650 square meters. A Volvo Ocean Race boat has a mast of 29 meters (from a point 2.5 meters above waterline) with a maximum Main Sail Area and Headsail area of 175 square meters each and spinnakers of 350 meters each.  So the Volvo Ocean Racer's three largest sails including kite are on a higher mast and have only slightly more sail area than a dhow's single sail - which is on a boat without any keel at all, let alone a canting keel.

How does the dhow rigging work?  I snapped the photo above at the Volvo stopover and was mystified - one mast with the long boom (in two pieces) with the sail attached to it and to the bowsprit - all inside the shrouds.  I couldn't work out how they managed to get the sails up, let alone tack or gybe, and end up looking like this:

Can you figure it out?  No fair googling.  Answers tomorrow.

1 comment:

  1. Nice post.

    Looks like a 4,000 year old design for an asymmetric kite.

    100 Races


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