|Here are two links to information. The first is a photo of INMA's boom with lazy jacks that also act as a topping lift. The second link is to a discussion on lazy jacks. |
The rig of the US built RL24s may have a heavier mast than the Australian RLs (looking at the photos). In Australia, most RL24s have masts with very light tips that should not be loaded with the forces of the topping lift. Most sailers run the spinnaker halyard back and secure the boom acordingly.
The latter yachts with roachy main sails do not run backstays and a topping lift could not clear the sail. INMA has a roachy main so I decided to rig a lazy jack that was strong enough to act as a topping lift when rigging. For the boom tent, I still rig the spinnaker halyard.