Junk Rig

I know, I know! It’s been almost three weeks since I posted anything. Ithere have been many things happening, but nothing much to do with drawing or with my boat so I thought I would spare you the drivel. I am editing my book. 100,000 words to edit, am about halfway through and needing (so far) to completely rewrite about 3-4000 of them. The rest are looking pretty well chosen (thank goodness!).

In boat news I got my copy of Hasler and McLeod’s Practical Junk Rig. Basically THE definitive tome on all things to do with Chinese style rigs. They are notoriously easy to sail, cheap to make and require minimum of stresses on both the hull and the sail. Perfect, no?

Thing is that my boat plans do not come with a junk option so I had to design one. It took all day and about eleven slightly different sails to arrive at the perfect configuration. I initially thought that you just plonk a siutable piece of cloth on a stick and call it a sail. Sadly it is about a hundred times more complicated and involves several things including your LWL, CLR, CE, rake and displacement (ballast in my case). You can see I am deliberately being cryptic.

Basically it is very important that the ‘average’ centre of pressure from the wind on the sail is more or less directly above the centre of lateral resistance of the hull. If not then your boat will not easily sail in a straight line, sacrificing speed and handling. If the point is too high above the boat then you will easily capsize, too low and you miss the swiftest winds. The height of your mast depends on the depth of your hull, so a little boat can’t have a tall mast because the mast will fall off and/or my boat will tip over in a gust. Finally the mast has to be the right proportions fore and aft of the mast to allow space for the rigging, and the right height above the boat to not hit you or trail in the water.

Anyway brace the contents of your various sphincters for the finished article!

 

image

I know…amazing…

Anyway, the important thing is I have plenty of sail (15 sq ft) and my CE is above my CLR, and my mast is a decent 19/20 ft. It should go like a scolded cat even in light breeze but I will have to reef early or risk taking a dip.

I was tempted by many things, extra masts, funky sail shapes, but I am going to keep it simple, this time.

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