Sub-surface Lightship Keying Format
| Position | Field Description |
| 1 - 28 | Lightship name (e.g. Diamond Shoals); left justify, blank filled |
| 29-34 | Latitude (e.g. Diamond Shoals = 350530; degrees, minutes, seconds) |
| 35-41 | Longitude (e.g. Diamond Shoals = 0751930; degrees, minutes, seconds) |
| 42-45 | Year |
| 46-47 | Month |
| 48-49 | Day (01-31, plus 99 = monthly mean) |
| 50 | Water depth indicator (1 = feet, 2 = meters) |
| 51-54 | Depth of water; right justify, zero filled (e.g. 0200 feet or 0055 meters) |
| 55 | Temperature indicator (1 = Fahrenheit, 2 = Celsius) |
| 56-58 | First level (surface) temperature; right justify, decimal implied, zero filled |
| 59-61 | Second level (30'/9m) temperature; right justify, decimal implied, zero filled |
| 62-64 | Third level (50'/15m) temperature; right justify, decimal implied, zero filled |
| 65-67 | Fourth level (100'/30m) temperature; right justify, decimal implied, zero filled |
| 68-69 | Fifth level (150'/46m) temperature; right justify, decimal implied, zero filled |
| 70-72 | Sixth level (200'/55m) temperature; right justify, decimal implied, zero filled |
| 73-76 | Salinity o/oo (surface level) |
| 77-80 | Salinity o/oo (near the water column bottom; e.g. Diamond Shoals 180-200 feet / 53-55 meters) |
Note: blank fill if value is missing. Exact depth that the temperature was sampled will be documented in the metadata (published data from which the data were keyed).