Owl: my current junk-rigged boat

I thought I’d describe my current junk rigged boat and show some of the design features. The boat is called Owl because it is green (as per The Owl and the Pussycat).

The boat is a 11′ GRP clinker-style boat originally built in the early 1980s for a gentleman to take his kids out in. I suspect it was adapted from a standard hull – probably designed for rowing or fishing. It had:

  • A flat centreboard that is a bit far aft;
  • A rudder that only just touched the water;
  • A standing lug rig that wouldn’t go upwind, with heavy yard and boom that reduced stability and threatened to hit heads.

However it did have a free-standing mast and, without the lug-rig up, was extremely stable. A perfect candidate for a junk rig!

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Mast partners sorted!

Figured out how to secure the mast at the partners. The rear chock now is ornamented by two bits of aluminium:

  • A plate on the bottom at the back to stop the back rising when the chock is pulled towards the mast;
  • A lashing point on the top of the block.
Rear mast chock with aluminium bits

In use it works like this:

Mast lashed in position

This is quick and easy to set up and very secure. I can lift the bows of the boat by pulling on a line to the mast top without any sign of the mast or chocks moving. As with all these things, once you figure out how to solve the problem it is easy and obvious.

Mast update

Got the mast strengthener in today. I was assuming that it would just slide in; however it jammed after a bit probably due to grit somewhere. Every time I took it out and cleaned it up (filing off the scratches) it jammed again, so I hammered it in using a wooden mallet. Fortunately it went all the way in without jamming completely. Phew.

Strengthener in with the aid of 3-in-one oil and a big hammer

I put the mast foot back on with locktite thread lock on the screws – I don’t want them coming out under sail.

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Calculating junk rig sail camber

I want a cambered sail for the advantages it gives us – better performance particularly close to the wind. There are disadvantages for ocean travellers – the sail can flap about in light winds and swell – but these don’t affect a dinghy (hopefully!).

This is my approach to calculating how to make the sail. There are others, and there may be errors in my calculations – if you spot any please let me know.

If you want to skip the maths there is a spreadsheet that you can plug the basic figures into. The maths is just to explain what the spreadsheet is doing – for me as much as anyone!

Update: before you build anything from this please read subsequent posts:

These cover tweaking the edges of the cloth to get good shape in the forward part of the panel.

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