Foreign Courtesy/Visitor Flag - Australia
Dimensions: 12" x 18"
This small craft courtesy flag is constructed as the specified "civil ensign" of Australia in proper design and proportion. It's made of Nylon with brass grommets. Note that the civil ensign or Merchant Flag of any country is not necessarily the national flag of that country.
As a gesture of courtesy, visiting cruisers should fly the specified courtesy flag of their host country when they enter and operate in its waters. Generally, cruising yachts under 60 feet select 12" x 18" or 12" x 24" flags. Larger yachts may want 16" x 24" or larger flags. There is no size requirement, so if you prefer the look of a larger flag, then fly it, but make sure that it clears a 360° fly from your spreader halyards (sailboat/powerboat) or bow (powerboat) or that flag will soon be in tatters.
As noted in Chapman's Piloting & Seamanship, a visitor flag is normally NOT hoisted until the vessel is properly cleared by customs and immigration. Until clearance is complete, fly the yellow Q (quarantine) flag.