| Definition | Symbol |
| Existence doubtful | |
| Sounding of doubtful depth | |
| Reported, but not confirmed, sounding or danger | |
| Sounding in true position | |
| Sounding out of position | |
| Least depth in narrow channel | |
| No bottom found at depth shown | |
| Drying heights and contours above chart datum | |
| Natural watercourse (in intertidal area) | |
| Area swept by wire drag. The depth is shown at Chart Datum. | |
| Kelp | |
| Sandwaves | |
| Spring in seabed | |
| Rocky area | |
| Coral reef | |
| Dangerline | |
| Depth cleared by wire drag sweep or diver | |
| Safe clearance depth. Obstruction over which the exact depth is unknown, but which is considered to have a safe clearance at the depth shown. | |
| Rock awash at the level of Chart Datum | |
| Underwater rock over which the depth is unknown | |
| Rock which covers and uncovers, height above Chart Datum, where known | |
| Underwater rock of known depth | |
| Breakers | |
| Wreck | |
| Foul area, not dangerous to surface navigation, but to be avoided by vessels anchoring, trawling, etc (e.g. remains of wreck, cleared platform) | |
| Navigation light on stranded wreck | |
| Obstruction or danger to navigation | |
| Stumps of posts or piles, wholly submerged | |
| Submerged pile, stake, snag or stump (with exact position) | |
| Fishing stakes | |
| Fish trap, fish weir, tunny nets | |
| Fish haven, with minimum depth | |
| Marine farm |
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