Why are these two fittings on my mast?

[Roy M]

The bar traversing the mast section is actually a bolt contained inside a tube, called a compression post. Its function is to hold the tangs that attach to the mast and the tube keeps the mast section from squishing (hence compression tube) when the nuts attaching the tangs are tightened. If one disassembles the hardware (as one would do if overhauling and repainting the mast), one would find the hole on one side is bigger than the hole on the other. This allows the compression post (bolt) to be withdrawn with the compression tube still frozen with galvanic crud. If the bolt head is on the wrong side of the bigger hole (guess how that happens), one has to hacksaw off the bolt head to extract the compression post. It's a royal pain, but then, it adds a certain drama to mast overhauls. Every sailor should get the opportunity to overhaul their mast just to know what the various parts actually do and how screwed up things can get from folks who didn't have a clue doing the work. Sorry, my rant is over, but it was very satisfying while it lasted (for me, at least).

[artisanmach]

Solent or inner stay, I have the same set-up in my boat. on my last haul out I added fittings for running back stays and ran the halyard internally.