This is a channel marker, placed on the edge of a channel. Green markers will always have an odd number on them. If you are heading upstream it should be to your left. If you are heading downstream it should be to your right. It will be opposite a red marker or bouy with an even number on it. To aid in navigating, the term "red, right, returning" is used meaning as you return from open waters (head upstream), the red marker, bouy, sign etc, should be to your right. That means the green one, in your example with a 3 on it, should be to your left. If its on your right side, you are outside the cleared channel area.
Keep bouy on port side
This is a channel marker, placed on the edge of a channel. Green markers will always have an odd number on them. If you are heading upstream it should be to your left. If you are heading downstream it should be to your right. It will be opposite a red marker or bouy with an even number on it. To aid in navigating, the term "red, right, returning" is used meaning as you return from open waters (head upstream), the red marker, bouy, sign etc, should be to your right. That means the green one, in your example with a 3 on it, should be to your left. If its on your right side, you are outside the cleared channel area.
Since this is a Green Lighted Buoy sighted while approaching a harbour,this is a Lateral port hand side mark, IALA region B. To keep this buoy on your port side while travelling upstream.
Keeping it on your port, passing it to starboard, will prevent your running aground.
As you enter a harbor from the open sea, you see a lighted buoy bearing the number 3. How should you pass it?
That normally means that there is a beacon on the top of the tower - These beacons can be red to warn of the towers height - most tall obstructions on the perimeter and approach to an airport will also have a red light for pilots to see. Beacons can be used on the tower to show a pilot the type of airport they are approaching Some of the most common used are; White and Green - Lighted land airport Green alone - Lighted land airport White and Yellow - Lighted water airport Yellow alone* - Lighted water airport Green, Yellow, and White - Lighted heliport White, White, Green - Military Airport White, Green, Amber - Hospital and/or Emergency Services Heliport
entering a harbor from the open sea, ther is a lighted buoy bearing the number 6, how should i pass it
keep the bouy on your starboard side
This is what causes the so-called "phases" of the moon: although fully half of the moon is lighted, we can only see part of the lighted part. A person on earth hardly ever sees all of the lighted side of the moon. When he does, he calls the sight a "full moon."
One half of the moon, the side that faces the Sun, is always lighted. But we usually see only part of the lighted side (phases) as the Moon orbits the Earth. When the Moon is directly between the Earth and the Sun (a new moon) none of the lighted side, facing the Sun, is visible from Earth.
quarter moon
Red to the Right, Returning. Keep the red buoy to the right side as you enter the channel.