Adding a boom vang
A vang used primarily for sailing off the wind can under go tremendous loads for a boat of this size and larger. If you plan to purchase a rigid vang and use it to support the boom in lieu of a topping lift as well, it should have a beefy fittings at the connection points of the boom and mast. NEVER use self-tapping or self-threading fasteners for any of this hardware, use only machine screws into tapped holes. When tapping holes into thin walled aluminum, always use the designated drill size and a forming tap, that is to say, a tap that has no flutes but actually cold forms the thread which doubles the strength of the tapped hole. I would recommend a Hall or Performance rigid vang and buy the suggested fittings from the vang manufacturer to suit the profile or shape of your boom and mast, they’re available in a wide variety shapes.