Which way do wooden booms taper????

pvb

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I was out at a friend's house for supper yesterday, and there in the garden was the wooden boom off his much-loved traditional wooden boat (which has been in restoration for the majority of the 13 years since he bought it!). Anyway, I took a look at it, and was intrigued to see that it tapered at the gooseneck end. This seemed rather odd to me, but my friend insisted that all wooden booms taper at the gooseneck end. He couldn't offer any explanation for this, and agreed with me that it seems to defy mechanical logic. Any ideas??
 

Mirelle

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Is it a roller reefing boom for a bermuda rig mainsail or mizzen? If so, it should have a more or less even taper from the clew end to the gooseneck, with a reduction of 1/12 or so in diameter over the length. This is to prevent the clew drooping when the sail is rolled.

Gaff roller booms do not have this feature, because a gaff sail rolls differently, but a gaff boom for roller reefing may taper evenly from the middle towards the ends to flatten the sail as it is rolled. Only a slight taper is called for in this application.

A points reefing boom for a laced foot sail will normally be parallel over its length, but may taper a little at the gooseneck end to accomodate the build up of sail luff rope when reefed.

A boom for a loose footed sail will have quite a pronounced taper from the middle towards both ends, but the outboard end may appear to taper less because of the bee blocks and reef combs.
 

AndrewB

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For roller reefing ...

A far lighter though less elegant solution is to have a wedge screwed to the aft half of the boom. This is necessary anyway with ali booms.

A temporary expedient is to wrap a towel into the back part of the sail as you reef.
 
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Further details of an answer to your question can be found in John Leather's excellent book "Gaff Rig" page 25 including diameter to length ratios etc.
 
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