Final answer:
A safe water mark that can be passed close aboard on either side is painted with red and white stripes and is lighted with a Morse code 'A' light.
Step-by-step explanation:
A safe water mark that can be passed close aboard on either side is painted with red and white stripes and is lighted with a Morse code 'A' light. The red and white stripes make the mark highly visible and easily recognizable to mariners. The Morse code 'A' light also helps in providing additional visual identification of the mark.