The design of standard factory fitted single reefing system on our Sun Odyssey 34.2 left something to be desired as there was too much friction in the system which resulted in poor shaped reefs being pulled in.
However the same section Sparcraft/Isomat booms are fitted by Beneteau to a number of the mid sized Oceanis yachts (eg 321), which are fitted with "shuttle blocks" which float loose within the boom - as shown in drawing below:
This system can easily be retrofitted. It requires the jam cleat to be replaced by a pulley, a fixing cleat riveted in the boom end to tie-off the pennant, and the shuttle blocks installed.
I had my boom alerted by sailspar the UK Sparcraft agent. But if you have a pop-riveter and the parts it is a straight forward conversion.
The reef now goes in with far less friction and can be done almost completely by hand, winching only needed at the very final stage. Also the sail sets much better.
Note new rivets on leftside which support new bracket which pennant outhaul is tied.
Boom end modified with jammer replaced by new roller.