put a 360 degree white at your stern. This complies with international colregs. Actually, the masthead light is a compromise. On boats shorter than some specified length (which I forget), the stern light can be omitted. By adding a stern 360 you are in full compliance with colregs for larger vessels.
PS. Hello from Juneau AK. We have been on a cruise for the last month. Went up the inside passage. After visiting Glacier Bay National Park and Sitka we will be heading south.