04 June, 2011

Lateen me and let's go Dhow

I've been researching sailing rigs on the internet. Without a background in sailing stuff across the water,  'tis a hard navigation .  But my preference is shifting toward, what's called in the scene, a lateen sail.  You can't get much simpler than a lateen.

Often seen as an archaic sail rig, the major lateen usage today is in the Indian Ocean -- the Dhow -- and in the Pacific , the Proa.

The proa is also referred to as the 'crab claw' sail

This aint fancy rigging as lateens are well short of the demands of the Sydney to Hobart but this is the sail that peopled both oceans with humans . It got them where they were going, despite its limitations.

Proa
Dhow

Inasmuch as I'm acquainted with the business, the main difference between the two sails is that the dhow does not utilize a bottom spar as the sail cloth  is allowed to run free and is lashed to the rear of the boat. In contrast the proa has sharply defined profile stretched between two spars.

Generally the proa is a more efficient way to harness the wind than the dhow. However, the way I see it the simplicity of the dhow and the fact that it has only one diagonal spar is an immense advantage when 'sailing' a small craft such as mine. (That's the assumption anyway).
The lateen sail on the dhow looks triangular to the casual observer, but in fact it is quadrilateral and is correctly termed a settee sail. Was sail is made of several cloths, sewn parallel to luff and leech. Different types of sail were made according to the requirements: a sail wanted for reaching would be made less flat and with a fuller luff than a sail wanted for beating.
The lateen yard was normally very long in proportion to the mast and hull, and was sometimes made of more than one piece of timber. In this case, it was fitted with a strengthening piece, along the middle. Two holes were them made so that the halyard type could be secured to prevent it from slipping along the yard. On a yard of very great length a second strengthening piece would be fitted along the middle of the first.(ref)
The dhow also stows away easily and is , I'd hoped, quickly reefed. Nonetheless, despite its seemingly crude nature -- a sheet hung from a clothesline -- it works .

Know your sails: Settee: middle top row. Lateen: top row right

So in way of summation: I guess the reality is that while the lateen is in the rigging ballpark, the detail lies with the Settee. The illustration above (click on image to enlarge view) gives you a profile comparison between sails. Inasmuch as I know the drill, beside the question of surface area, the profile of a sail impacts on its efficiency to harness the energy of the wind.

That said, I'm after a rig that will skim me acros the shallow waters of Moreton Bay and with that perspective, I came upon  images of sailing boats (sample below) from the Sandgate Yacht Club which gives you some of the context I'm engaged with. The photographs are probably from the inter war years  and they illustrate a penchant for  'plenty of sail' . I'm very familiar with Bramble Bay area and note that these craft are being sailed close in to shore, up against the mud flats that lead into the Boondall Wetlands.Shallow waters indeed.
How prescient is that? I'm one bay away -- on Decepion Bay -- keen to learn to  do the same.