[tdw]

I have absolutely no idea about the "Islander Excalibur" though from the pics that google throws up she looks like a fairly typical prod sailor of her day.

As to whether you could or should circumnavigate in one I offer no opinion but if you spent a few months sailing up and down the coast near your home port you might just find out for yourself whether you have a suitable craft for this planned voayage around the planet.

Indeed, said craft might also find out is she has a suitable skipper.