Danger messages: storms, force 10 winds and severe icing (SOLAS V/31–32)
1The lesson in plain words
Under SOLAS V/31 every master must report certain dangers to ships nearby and the authorities. V/32 says what each message should contain.
The duty
SOLAS regulation V/31 binds the master of every ship, not only VOS ships. If you meet dangerous ice, a dangerous derelict or any other direct danger to navigation, a tropical storm, sub-freezing air with gale-force winds causing severe ice accretion on the superstructure, or winds of force 10 or more for which no storm warning has been received, report it by all means at your disposal to ships nearby and to the competent authorities.
Form and cost
The form is not fixed: plain language, preferably English, or the International Code of Signals. Send it as a safety message to ships in the vicinity and to the nearest coast station or authority. These messages are free of cost to the ship. Operating the radio equipment is covered in the communication units.
Tropical storm content
SOLAS V/32 asks you to report a tropical cyclone when you have good reason to believe one is forming or near. Give UTC, date and position. Add available observations: pressure with unit and correction status; change over three hours; true wind direction and Beaufort force; sea state; swell amount, true direction and period or length; and true course and speed. While affected, further reports are desirable hourly if practicable, at intervals of no more than three hours.
Force 10 and icing
For winds of force 10 or more with no storm warning, meaning a storm other than a tropical cyclone, send similar content without the sea and swell details. For severe icing, give time and date, air temperature, sea temperature if practicable, and wind force and direction. Ice and derelict reports give what you saw and its position. Avoiding the storm itself is in Tropical revolving storms.
2Key data
- Triggers (V/31)
- Ice, derelict, other danger, tropical storm, icing, force 10 unwarned
- Who reports
- The master of every ship, VOS or not
- Form
- Plain language (preferably English) or the Code of Signals
- Storm follow-up
- Desirable: hourly if practicable, at least every 3 hours
- Cost
- Free of cost to the ship
3Key points
- 1
V/31 is mandatory for every master, unlike VOS reporting.
- 2
Non-tropical force 10+: report if unwarned. Report suspected tropical cyclones even if warnings have been received.
- 3
Icing reports need sub-freezing air and gale-force wind causing severe accretion.
- 4
Tropical storm: position, time, pressure (corrected or not), wind, sea, swell, course and speed.
4Frequent mistakes
Wrong: Danger messages are only for ships in the VOS scheme.
Right: SOLAS V/31 binds the master of every ship.
Wrong: Wait until you are sure a tropical cyclone has formed before reporting.
Right: SOLAS asks you to read the duty broadly: report when you have good reason to believe one is forming or near.
5Practice case & exam keys
At 0600 UTC on 12 January, at 48°30′N 025°10′W, you meet non-tropical true wind WNW force 10 without a storm warning. Corrected pressure is 978.4 hPa, down 6 hPa in 3 hours. Your true course is 080°, speed 9 knots. What do you report?
Show the answer
This is a V/31 trigger: non-tropical force 10 with no storm warning received. Send a danger message to nearby ships and the competent authority: “Storm. 0600 UTC 12 January. 48°30′N 025°10′W. Barometer corrected 978.4 hPa, falling 6 hPa in 3 hours. True wind WNW force 10. Course 080°T, speed 9 knots.” Use the observed values supplied; do not invent missing readings.
Exam keys
- V/31 triggers: dangerous ice or derelict, other direct danger, tropical storm, severe icing, unwarned force 10.
- Message: plain language or Code of Signals, to nearby ships and competent authorities.
- Further tropical-storm reports are desirable while affected: hourly if practicable, no more than 3 hours apart.
Finish this unit
When you've read it, match the terms, then answer three questions. Get them all right to finish the unit; opening the page alone doesn't count.
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