Lateral Special Marks Ireland IALA-A Buoyage System

Lateral Marks (Go To Top) Mouse over chart to enlarge, click on chart for large map. Lateral marks indicate the sides of a channel, and under the IALA-A System when returning to port, green marks are kept on your starboard side and red marks are kept on your port side (Green Right Returning). If lateral marks are lighted, their lights are green (starboard side) or red (port side) in Region A.
This green buoy with the letter “A” is left on our starboard side as we motor up the Firth of Clyde Channel in Scotland, passing to the west of Great Cumbrae Island. View Chart - Red Arrow #5 -- 270 KB
This red mark has a continuous quick flashing red light (Q. R) and marks the port side of the channel when entering Castletown Bearhaven (Castletownbere) harbor in Bantry Bay, Ireland. View Chart - Red Arrow #1 -- 224 KB
This red beacon with the can-shaped topmark is passed on your port side to stay clear of a rocky area called “The Dangers” when entering Glandore Harbor, Ireland. View Chart - Red Arrow #3 -- 254 KB
Here is a red beacon with a can-shaped topmark positioned near “Colt Rock.” It should be passed on your port side when using the West Entrance to get to Castletown Bearhaven (Castletownbere). West of the mark is an anchorage which is near Dunboy House Ruin. View Chart - Red Arrow #2 -- 224 KB
Special Marks (Go To Top) Mouse over chart to enlarge, click on chart for large map. These yellow marks denote a special feature or area, such as a military zone, traffic separation scheme, pipelines, spoil areas or a scientific buoy. If these marks have a topmark (optional), it will be a yellow X. Lighted marks will have a yellow light. This buoy with the letter “B” marks the intersection of the Firth of Clyde Channel and Skelmorlie Channel. Both of these channels fall under Rule 9 (Narrow Channels) of the International Regulations for Preventing Collisions at Sea (1972). Skelmorlie Channel is a northbound channel for vessels with a draft of more than 15 meters (49 feet). View Chart - Red Arrow #4 -- 270 KB
Safe Water Mark. This example shows a Safe Water Mark identifying the middle of a channel and has a long flash. This mark indicates navigable (safe) water on all sides of the mark. Color: Red and white vertical stripes Shape: Sphere or buoy with a red spherical topmark In the US, Safe Water Marks may not have a topmark. Characteristic: Letter(s) Light: White light, if lighted. If the mark is used to identify an offshore approach to a channel or major port, it will have a light flashing the Morse Code (Mo) signal for the letter "A" (1 short flash followed by 1 long flash). View Chart - Red Arrow #3 -- 270 KB
Isolated Danger Mark This mark is placed near an isolated danger with navigable water all around. It is infrequently used in the US. Color: Black and red horizontal bands Topmark: Two black spheres Light: If lighted they display a group of two white flashes every 10 seconds. View Chart - Red Arrow #ID -- 180 KB

Range (Go To Top) Mouse over chart to enlarge, click on chart for large map.

A range is a pair of markers used to determine a line of position. In this example, if you line up the two markers, it will guide you down the middle of the entrance to Castletown Bearhaven (Castletownbere) harbor, Ireland.

View Chart - Red Arrows #R1 & #R2 -- 224 KB

When the front (bottom) marker is to the right of the rear (top) one, you are to the left of the range. You should turn right (starboard) to get onto the
range line.

The two range markers are in line,
which indicates you are on the
range line.

When the front (bottom) marker is to the left of the rear (top) one, you are to the right of the range. You should turn left (port) to get onto the range line.