Our boat is US registered. While in Qld. (Queensland, Australia), we were stopped, and told that the dinghy
with its 15 hp o/b had to be registered, which was correct for Queensland
, if the boat was Australian registered (which requires Australian citizenship). However, since the dinghy is clearly marked as a tender
to a foreign registered vessel, it
is actually outside their jurisdiction. They don't like it, but eventually they "got it." The incident occurred prior to 9/11. Haven't been bothered much lately.