Re: Is the halyard the only support for the boom
No one has mentioned another option for holding up the boom at anchor: a boom crutch. Hoisting the sail generally lifts the boom up off it, so removing it is simple. It also provides a piece of wood that might come in handy in some emergency situations. (Jury rudder/tiller/bumper board/splint for boom...) A boom crutch is obviously not helpful for reefing, but a spring-loaded rigid vang has worked for us since 1997 w/o replacing any springs, and we've done a reasonable bit of reefing when we've needed to.