6.3 KiB
IALA Buoyage System — Complete Rules Reference
Source: IALA/AISM Publication R1001 (5th edition, 2010); IHO S-57 Object Catalogue; INT-1
Region Overview
| Region | Coverage |
|---|---|
| A | Europe, Africa, Asia (including Middle East, India, SE Asia, China, Australia, New Zealand) |
| B | Americas (North, Central, South), Philippines, Japan, South Korea |
The only practical difference between Region A and B is the lateral mark colour convention (red/green sides are swapped). All other marks (cardinal, isolated danger, safe water, special) are identical.
1. Lateral Marks
Lateral marks — Region A
| Mark | Colour | Shape | Topmark | Light rhythm | Light colour |
|---|---|---|---|---|---|
| Port hand (pass on port side) | Red | Can / Cylinder | Red can (if any) | Any (Fl R common) | Red |
| Starboard hand (pass on stbd) | Green | Conical | Green cone point up (if any) | Any (Fl G common) | Green |
| Preferred channel — port hand (modified port) | Red with green band(s) | Can | Red can | Fl(2+1) R | Red |
| Preferred channel — stbd hand (modified stbd) | Green with red band(s) | Conical | Green cone point up | Fl(2+1) G | Green |
Lateral marks — Region B
| Mark | Colour | Shape | Topmark | Light rhythm | Light colour |
|---|---|---|---|---|---|
| Port hand | Green | Can / Cylinder | Green can (if any) | Any (Fl G common) | Green |
| Starboard hand | Red | Conical | Red cone point up (if any) | Any (Fl R common) | Red |
| Preferred channel — port hand | Green with red band(s) | Can | Green can | Fl(2+1) G | Green |
| Preferred channel — stbd hand | Red with green band(s) | Conical | Red cone up | Fl(2+1) R | Red |
S-57 CATLAM attribute: 1=port, 2=starboard, 3=preferred_channel_to_stbd (vessel keeps to starboard = mark acts as port), 4=preferred_channel_to_port
2. Cardinal Marks (same in both regions)
Direction refers to where the mark is placed relative to the danger (e.g., a North cardinal is placed NORTH of the danger — pass to the north).
| Mark | Topmark | Colours (top→bottom) | Light rhythm | Light colour |
|---|---|---|---|---|
| North | 2 cones point UP | Black over Yellow | Q (60/min) or VQ (100/min) | White |
| East | 2 cones base-to-base | Black/Yellow/Black | Q(3) 10s or VQ(3) 5s | White |
| South | 2 cones point DOWN | Yellow over Black | Q(6)+LFl 15s or VQ(6)+LFl 10s | White |
| West | 2 cones point-to-point | Yellow/Black/Yellow | Q(9) 15s or VQ(9) 10s | White |
Memory aid for topmarks: cones point TOWARD the black portion.
- North = both black (top), cones point up
- South = both black (bottom), cones point down
- East = black both top and bottom, cones point apart (base together)
- West = black in middle, cones point together
S-57 CATCAM: 1=North, 2=East, 3=South, 4=West
3. Isolated Danger Mark
Placed ON or OVER an isolated danger of limited extent with navigable water all around.
| Attribute | Value |
|---|---|
| Colour | Black with one or more broad horizontal RED bands |
| Shape | Pillar or spar |
| Topmark | 2 black spheres (vertically in line) |
| Light | Fl(2) White |
| Light period | 5s typical |
S-57 layers: BOYISD (buoy), BCNISD (beacon)
4. Safe Water Mark
Indicates safe navigable water all around — used for mid-channel, landfall, or fairway axis marks.
| Attribute | Value |
|---|---|
| Colour | Red and white vertical stripes |
| Shape | Spherical (preferred), pillar, or spar |
| Topmark | Single red sphere |
| Light | Iso W, Oc W, LFl W 10s, or Mo(A) W — any white rhythm not used for other marks |
S-57 layer: BOYSAW
5. Special Purpose Mark
Not primarily intended to aid navigation — marks a special feature or area.
| Attribute | Value |
|---|---|
| Colour | Yellow |
| Shape | Any (optional X topmark) |
| Topmark | Single yellow X (optional) |
| Light | Yellow, any rhythm not already used by other marks in the area |
Uses: traffic separation schemes, spoil grounds, military exercise areas, cables/pipelines, ODAS buoys, recreation areas, ferry crossings.
S-57 layer: BOYSPP
6. Emergency Wreck Marking Buoy (EWMB)
Introduced by IALA 2006, for newly discovered dangerous wrecks before standard survey/marking.
| Attribute | Value |
|---|---|
| Colour | Blue and yellow vertical stripes (alternating) |
| Shape | Pillar or spar |
| Topmark | Single upright yellow cross |
| Light | Al.Bu.Y 3s (alternating blue / yellow) |
| AIS | AIS AtoN transmitter active if fitted |
| RACON | Morse "D" (— . .) if fitted |
Deployed in pairs when possible, one on each side of the wreck. Removed once proper marks or formal notices are in place.
7. New Dangers (S-57 / ECDIS)
A newly discovered hazard (shoal, wreck, obstruction) not yet charted or inadequately charted is marked by:
- One or more cardinal or lateral marks as appropriate
- Identical mark may be doubled for emphasis
- ECDIS may show a "New Danger" highlight
8. Fairway and Mid-Channel Buoys
On wide rivers, lakes, and channels a single line of buoys may be laid along the fairway centreline — these are safe water marks (red/white) or may be lateral depending on the traffic pattern.
9. Light Phase Descriptions — Standard S-52 / INT-1 rhythms used on IALA marks
| Rhythm | Typical period |
|---|---|
| Q | 1s (60/min) |
| VQ | 0.5s (100–120/min) |
| Fl | 3s–10s depending on group count |
| Oc | Equal or longer eclipse; period 4s–12s |
| Iso | Equal on/off; period 2s–8s |
| LFl | Flash ≥ 2s; period 10s typical |
| Mo(A) | Morse A (. —); period 6s |
10. S-57 Layer to IALA Mark Type Mapping
| S-57 Layer | Mark type | AidsMonitoring classify() result |
|---|---|---|
| BOYLAT / BCNLAT | Lateral buoy / beacon | LATERAL_PORT, LATERAL_STBD, LATERAL_PREF_PORT, LATERAL_PREF_STBD |
| BOYCAR / BCNCAR | Cardinal buoy / beacon | CARDINAL_N/E/S/W |
| BOYISD / BCNISD | Isolated danger | ISOLATED_DANGER |
| BOYSAW | Safe water buoy | SAFE_WATER |
| BOYSPP | Special purpose buoy | SPECIAL |
| LIGHTS | Light (point) | LIGHT_POINT |
| LNDMRK | Landmark | LANDMARK |
| RTPBCN | Racon | RACON |