Avoiding action near a tropical cyclone
1The lesson in plain words
If you are caught near a storm, find your quadrant, then put the wind where it carries you away from the centre: in both hemispheres.
Planning comes first
In seasonal basins, sail outside the main season and keep clear of forecast storms. At 6 knots a yacht covers 144 miles a day; at 15 knots a storm covers 360. The actions below, from NHC and Bowditch, are last resorts. The angles select an initial course. While storm direction and speed stay steady, hold that compass course as the wind shifts, as sailing conditions and sea room permit. Monitor and reassess; do not rely on outrunning a cyclone.
Northern hemisphere
Confirm your quadrant by advisory; trends are clues. Dangerous semicircle, ahead (wind veering, pressure falling): put the wind about 45° on the starboard bow and make the best speed you can; sail close-hauled (as near the wind as practicable) on starboard tack. Navigable semicircle, ahead (wind backing): put the wind about 135° on the starboard quarter. On the track, ahead (steady wind, pressure falling): put the wind about 160° on the starboard quarter and run into the navigable semicircle.
Southern hemisphere
Mirror the north; confirm your quadrant from the advisory. Dangerous semicircle, ahead (wind backing, pressure falling): wind about 45° on the port bow, best safe speed; a yacht initially close-hauled on port tack. Navigable semicircle, ahead (wind veering): wind about 135° on the port quarter. On the track, ahead (steady wind, pressure falling): wind about 160° on the port quarter, into the navigable semicircle. Behind: keep wind on the starboard side north, port side south; adjust course and speed for the best ride and monitor the track.
If you must heave to
Heave to on the tack that lets the shifting wind draw aft, towards your stern. North: starboard tack in the dangerous semicircle, port tack in the navigable one. South: port tack in the dangerous semicircle, starboard tack in the navigable one. Never run with wind and sea on the quarter in the front of the dangerous semicircle: that carries you towards the centre. Storm tactics has its own unit.
Don't cross the T
Crossing ahead of a storm's track is the classic fatal mistake: a breakage or a loss of speed leaves you in its path. Passing behind it is far safer, even if the route is longer. Re-plot after every new advisory, every six hours.
2Step by step
When a storm threatens
- 1
Get the latest advisory; plot the centre, track and 34-knot radii.
Your position relative to the storm decides everything that follows.
- 2
Start logging true wind and pressure now; keep recording while you act. Do not delay avoiding action.
Trends help check your plotted position; they take time to establish.
- 3
Use the advisory to establish your quadrant; cross-check with observed trends.
The northern and southern rules are mirror images; mixing them is fatal.
- 4
Choose the indicated initial course and make best safe speed. While storm direction and speed stay steady, hold that course as the wind shifts, as sailing conditions and sea room permit.
The wind angle selects the course; keep monitoring the track and reassess when storm motion or sailing conditions change.
- 5
Never cross ahead of the track; pass behind if you must cross.
Damage or lost speed ahead of the storm leaves you in its path.
- 6
Re-plot with every new advisory and adjust early.
Tracks change; a small early change beats a large late one.
3Key data
- North, dangerous, ahead
- Wind about 45° on the starboard bow, best speed
- North, navigable or on track ahead
- Wind about 135° (160° on track) on the starboard quarter
- South, dangerous, ahead
- Wind about 45° on the port bow, best speed
- South, navigable or on track ahead
- Wind about 135° (160° on track) on the port quarter
- Heave to (north)
- Starboard tack dangerous; port tack navigable
- Heave to (south)
- Port tack dangerous; starboard tack navigable
4Key points
- 1
North, dangerous semicircle: wind on the starboard bow. South, dangerous semicircle: wind on the port bow.
- 2
Navigable semicircle or on the track ahead: run with the wind on the starboard (north) or port (south) quarter.
- 3
Heave to on the tack that lets the shifting wind draw aft, towards your stern.
- 4
Never cross ahead of a storm's track; pass behind it.
- 5
These are last resorts: in seasonal basins, plan outside the main season and keep clear of forecast storms.
5Frequent mistakes
Wrong: In any hemisphere, put the wind on the starboard bow in the dangerous semicircle.
Right: Starboard bow is the northern hemisphere rule. In the southern hemisphere it is the port bow.
Wrong: Run before the wind to escape fastest, wherever you are in the storm.
Right: In the front of the dangerous semicircle, running carries you towards the centre. Keep the wind on the bow there.
Wrong: Cross quickly ahead of the storm to reach the other side.
Right: Don't cross the T. A breakage or loss of speed would leave you in its path; pass behind it.
6Practice case & exam keys
In the North Atlantic, the latest advisory places you ahead and to the right of a north-west-moving hurricane. The true wind is veering and pressure is falling. Your 12 m sloop can sail close-hauled in the present 30 knots. What do you do?
Show the answer
You are ahead of the centre in the dangerous semicircle. Start with wind about 45° on the starboard bow, close-hauled on starboard tack, at best safe speed. While storm direction and speed stay steady, hold the selected compass course as the wind shifts, as sailing conditions and sea room permit. Do not run off. Re-plot each advisory; if you must heave to, use starboard tack.
Exam keys
- North, dangerous semicircle: wind 45° on the starboard bow; sailing yacht close-hauled on starboard tack.
- North, navigable or on the track ahead: wind on the starboard quarter, best speed away.
- South, dangerous semicircle: wind 45° on the port bow; navigable or on the track: wind on the port quarter.
- Don't cross the T: never pass ahead of a storm's track.
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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