Oh, the flipper thingie ... you can leave it or remove it.
It was on the early comp-tip masts but was later discontinued. It's purpose is for aiding in lowwering the sail, by allowing the sail to pass over the hook,

My TheMightyHobie18 has one my P-19 doesn't ... I actually like it as I don't have to rotate the mast to lowwer the sail, just "haul" up letting the flipper to drop in place and then the sail drops cleanly.

So Here is my other secret ... hoist the sail until the ring is just below the hook (note: I have the Halyard wrapped around my body/waist and am pulling with my legs). At this point I close my eyes and gently apply pressure/pull on the halyard ... FEEL THE HOOK ...you will feel the ring make contact w/ the underside of the hook ... gentle pull the ring onto the hook ... DO NOT YANK ... you only need to take in 1"-2" of halyard once you make contact with the underside of the hook.

FEEL THE HOOK ... OMMMMMMM ... OMMMMMM (its a Zen thing)

HarryMurphey