Quick answer
Delta is the International Code of Signals flag for D. Its single-letter message is: “Keep clear of me; I am manoeuvring with difficulty.” Its identifying pattern is yellow–blue–yellow horizontal stripes. The meaning is listed in the Hong Kong Marine Department’s Examination Guidebook; the colour sequence appears in the Singapore government-hosted signal chart.
| Item | Description |
|---|---|
| Code letter and phonetic name | D — Delta |
| Identifying pattern | Horizontal stripes in yellow, blue and yellow order. |
| Single-letter meaning | The signalling vessel is manoeuvring with difficulty; other vessels should keep clear. |
| Overall proportions | No exact hoist-to-fly ratio is established here. |
| Stripe dimensions | No numerical stripe-height specification is established here. |
| Colour standards | The consulted identification evidence names yellow and blue; it does not establish exact textile, Pantone, RGB or hexadecimal values. |
Construction and colour notes
The government-hosted identification chart supports the yellow–blue–yellow horizontal arrangement. This record does not treat that chart as a dimensioned manufacturing standard. Exact dimensions, stripe fractions, fabric requirements and colour tolerances remain unverified.
No common manufacturing ratio is asserted without a supporting specification. Screen colours would be approximations unless tied to a documented colour standard; a drawing made from the descriptive pattern alone would be an editorial reconstruction. Neither should be presented as an official construction specification.
Code context and history
The International Code of Signals provides complete messages for safety-related communication at sea, including situations where language differences make communication difficult. The IMO publication overview explains that the 2005 edition incorporated amendments through December 2000 and that its later presentation introduced minor editorial improvements. These are milestones in the Code’s publication history, not evidence for the adoption date of Delta’s individual design.
Delta is documented in the contemporary government signalling references cited here. The evidence consulted does not establish when its yellow–blue–yellow design first entered service.
Other maritime code flags
Explore Alpha, Bravo and Charlie.
Sources and evidence scope
- Hong Kong Marine Department, Examination Guidebook, Chapter 12: D / Delta single-letter meaning. Relevant indexed text consulted; the full PDF could not be retrieved.
- International Code of Signals (1969), chart marked updated to 1 August 2025, hosted on file.go.gov.sg: D, Delta and yellow–blue–yellow horizontal stripes. Relevant indexed text consulted; no dimensional specification verified.
- International Maritime Organization, International Code of Signals, publication overview: purpose and edition history; not a source for Delta-specific adoption dates or construction dimensions.