Jonathan's jib boom topping lift for a BRe is mentioned as one of his favourite modifications - see his library article
http://www.swallowyachtsassociation.org/?p=1087It is also useful for a BR20 and any other boat with a jib boom and self tacking jib. It keeps the shrouds under tension when the jib is furled and allows adjustment to jib leech tension, which is particularly helpful in light winds.
I used to use my spinnaker halyard for this but (very occasionally) needed that for the spinnaker. I have now adopted Jonathan's system of attaching a permanent topping lift directly to the jib halyard, just above the furler swivel, using a Barton high load eye - see the first photo below. The blue parrel ball is to prevent the topping lift (and any other string) from getting tangled up in the furler swivel.
Jonathan leads his topping lift straight down to a Clamcleat screwed to the end of the jib boom but on a BR20, this space is already occupied by the Clamcleat for the jib outhaul. The solution is to use a trapeze Clamcleat instead, allied to another Barton high load eye which is attached, in turn, to a loop around the bottom of the boom. This arrangement also gives some mechanical advantage. See the second photo.
This version of the topping lift does not seem to interfere with the swing of the jib from side to side. Employing the spinnaker halyard for the same purpose sometimes made the jib hesitate to swing in light winds, no doubt because the geometry was a bit different. The topping lift is exactly parallel to the jib leech, which seems to help.
There's plenty here to keep a knitting circle occupied.
