Boom not Bust

Boom not Bust Download a pdf version

The next item on the agenda is booms. Those of you with sprit rigs, bawleys and Drascombes can skip this article with impunity. For the benefit, I hope, of the rest of us, I am going to look in a simplistic way at the engineering of booms in this article, and the implications for the fittings and arrangements in the next. As with many aspects of the rig the boom, its design and fittings are ideally considered all of a piece.

Bits for Booms

Bits for Booms

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A reader of the last article on booms said that it was a bit inconclusive: he was trying to size a boom and couldn't. So before I move on to the details of boom fittings, here is a little guidance. There is a helpful table in the most recent edition of Skene's Elements of Yacht Design which gives sizes geared toward Bermudan yachts, so you may need to be careful about using it exactly. Alternatively, there is a rule of thumb which says that the boom, at least at the gooseneck end, should be around 65-75% of the mast diameter. How do you know what the mast diameter should be? Well, try the guidelines suggested in the second masts article which gave a consistent set of answers by a variety of methods. Alternatively, if your mast is OK in service, use that diameter!

The subject of this article is mainsail reefing. I’m just dealing with mainsails because I am still on the subject of booms, in case you were beginning to lose the plot of this series!

Reefing is rather like waking up in the middle of the night wanting to go to the toilet. However much you might wish it, you can’t go back to sleep, but instead spend precious minutes in a sort of “shall I, shan’t I?” routine. By the time you finally get up, you are thoroughly awake and wish you'd just got up in the first place. So it is with reefing; if you find yourself wondering if it is a good idea to reef, you are usually better off to do so. The temptation to press on has cost me at least one No. 1 Genoa, and two memorable entrances into harbours whose successful outcome was a lot more to do with luck than judgement. A key factor in the decision - of going to the toilet or reefing - is how easy it is to do. Hence the popularity of en-suite bathrooms and the purpose of this article.

Different ships, different saddles

In the good old days when gaffs lay at an angle of 45 to 50 degrees to the mast, the prime function of the gaff saddle or jaws was to accommodate the thrust of the gaff on the mast, and stop the thing falling off sideways. If you wanted to improve windward performance, you set a topsail. “Modern” gaffers tend toward the view that if you peak the gaff up higher and higher it goes better and you don’t have to muck around with topsails - the logical extension of which is Bermudan rig. It is not the place here to argue the pros and cons of high peaked gaff rig. But from the point of view of the fittings, as you peak the gaff up two things happen.