[/quote]

Maybe the intention is to leave reasonable headroom under the sail.

If the luff length is not limited, the highest aspect ratio (best performance) is achieved using the entire mast length for the luff. This reduces the headroom necessary for kids to move on the tramp, making the boat uncomfortable, less fun and potentially unsafe. [/quote]

Luiz,
yes there may be a performance gain, so Im all for that but I seriously doubt its unsafe....the opposite in fact because there is no boom to whack them on the head.

Attached pic is of the boomless rig on one of the LR2's which gave a ton of room to to get thru safely.
Cheers
RG