The Gray Monk

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December 06, 2005

Lines of grace

The dhows of the Arabian Gulf come in a wide range of sizes, but all share the same basic design and shape. There are small ones for use by a single man for fishing which can be rowed or sailed, there are the larger versions capable of short seagoing voyages and used for fishing, short sea trading and pearl diving - and then there are large versions which trade across oceanic distances between Arabia and India. In the days of sailing vessels - in fact right up to the mid-twentieth Century - these sailing dhows used to trade along the East African Coast, and across the Indian Ocean/Arabian Sea to India, Ceyl;on, Burma, Thailand and down the Indonesian Island chain. Some still do, but now are powered by large diesel engines as the one in the phot below was until it was abandoned where you now see it.

An abandoned dhow shows the graceful lines and shallow draft which give these craft their speed and ability to sail swiftly in shallow waters around the islands.

The sailing dhows carried either a single mast on the smaller vessels or a double mast arrangement on the large ocen going vessels. The lateen rig is not the handiest if you need to drive the vessel to windward by means of a series of "tacks", which requires the ability to change the side on which the sials are "set" in order to make the most efficient use of the wind. This was a major disadvantage of the "square" rig common on European vessels during the age of exploration and expansion, but it was more efficient in that it allowed a rapid change of direction which did not, as in the lateen rig, require the sails to be struck, hauled over the top of the mast and the long angled yard, and then reset on the opposite tack, a manoeuvre possible only where there was plenty of sea room or the vessel could be brought to anchor while the change was made.

A beautifully detailed model of a twin masted trading dhow showing the arrangement of the twin masts and the manner in which the sails are set.

As I could not get to a place where there are reputed to still be some fully rigged dhows, I have had to resort to a photograph of a presentation model of the double masted rig. Even on this scale the simple grace of the lines of the hull and of the rig show its simple beauty. While European sailing vessels of the 16th - 19th Century lumbered around the world at an average speed of 4 - 8 knots (around 5 - 10 miles per hour!), the dhows could regularly notch up speeds of 10 - 15 knots (11 - 17 mph) sailing along the monsoon winds between India and Arabia and between Arabia and the East Coast of Africa. On a broad reach these craft have a distinct advantage with a good wind as the hull form and the shallow draft allow the bows to lift and the ship adopts a "planing" attitude which reduces drag and increases the speed which can be achieved. The deep hulled design of European ships required considerably more effort to achieve anything like the speds the dhows could reach.

The rather sadly decaying timbers of this abandoned dhow show the inherent strength of the hull design and its yacht like lines.

A remarkable feature of the dhow design is that it has not changed a great deal in over a thousand years. You will not find any drawings for the design in any of the "yards" where they are still built, the design is all done by eye and experience and they vary individually as a result in dimensions, hull form and size. All in all, a remarkably durable and efficient design which has stood the test of time very well indeed.

Posted by The Gray Monk at December 6, 2005 08:12 AM

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Posted by: Deirdre Dudley-Owen at September 24, 2007 06:11 PM

Posted by: martin at December 4, 2007 10:44 AM