Reply To: OKDIA AGM: draft agenda
the booms are allowed to be 70mm deep as a minmum. Most are way more and some are tapered through the aft band as outside of that it is basically free area. Or has been treated as such anyway. Some were too tapered and being less than 70mm +/- 20mm had a can or something similar stuck in the end to make them comply.
This change makes booms that are rounded at the front so they do not hit the mast legal. That is basically all it is doing. If a boom was never legal it cannot be grandfathered as that can only apply when a rule makes something illegal that was previously alright. As the measurement includes sail track it really only affects the front end where this has often been cut away.
hope this explains it