Summary
Highlights
Captain Tom Tursi introduces the critical topic of storm avoidance for ocean sailors, highlighting its importance alongside avoiding other ships. He plans to discuss five specific case studies from ocean training cruises to illustrate decision-making processes and lessons learned during storm encounters.
Weather is constantly changing, and during long-distance sailing, conditions will not remain ideal. Sailors must be prepared to take calculated risks and avoid presuming favorable weather. Major weather windows (season and location) are planned using resources like ocean pilot charts and Jimmy Cornell's World Cruising Routes, while minor windows (daily/weekly) involve short-term departure decisions.
Ocean pilot charts provide historical statistical summaries of weather conditions for different oceans and months. They include information on wind roses (direction, duration, strength), current directions and speeds, and magnetic variation. Reviewing storm data, such as records of tropical cyclones and gale reports for the North Atlantic, helps in long-term planning for sailing seasons.
Hurricanes are intense low-pressure systems developing along the Intertropical Convergence Zone (ITCZ) in the North Atlantic, typically rotating counterclockwise. Key avoidance strategies include not crossing a hurricane’s forecast track and staying out of the dangerous semicircle (right side in the Northern Hemisphere). The Mariner's 1-2-3 rule helps delineate a cone of avoidance based on predicted storm positions and an increasing radius of uncertainty.
During a Norfolk to Bermuda trip, Tropical Storm Barry developed ahead, threatening to cross the vessel's path. Based on a voice weather forecast, the crew decided to turn away from Barry's forecast track, putting distance between them and the storm. By placing the wind on their starboard quarter while to the left of the storm's track, they successfully sailed away from the storm before resuming their original course.
Halfway between Bermuda and St. Thomas, Hurricane Olga formed 900 miles northeast and was forecast to move westward. With no port of refuge available in the open ocean, the crew decided to make maximum speed towards St. Thomas, betting that the storm would not turn south. Olga's southwest winds, however, cancelled out the usual easterly trade winds, requiring engine use. They successfully reached St. Thomas, entering through a wide passage to avoid dangerous breaking waves along the north side of the islands.
Departing Norfolk for St. Thomas, the crew faced an intense low off Cape Hatteras. They delayed departure initially. However, after committing to sea, the low intensified into Tropical Storm Sean and began moving towards them. They made the strategic decision to abort the passage and seek refuge in Beaufort, North Carolina, avoiding being caught in the Gulf Stream with opposing storm-force winds. After two days, Sean recurved northeast, allowing safe departure.
Tropical Storm Beryl was forecast to move southwest, then abruptly turn northeast along the U.S. East Coast, crossing the vessel's intended Norfolk-Bermuda route. Choosing to trust the forecast despite its unpredictability, the crew departed a day early to cross the cone of avoidance ahead of the storm. They performed extensive storm preparations at sea, including securing all loose gear, rigging storm sails, and notifying the Coast Guard. They successfully avoided the storm's core, experiencing only 35-knot winds.
Preparing to depart Norfolk for St. Thomas, an intense low was forecast to develop off South Carolina and intensify to hurricane force near Hatteras. The crew opted to depart a day early, on November 3rd, to get south and past the Gulf Stream before the storm developed. This allowed them to get "under" the developing storm, experiencing manageable westerly winds and smooth sailing towards their destination.
Key lessons include understanding basic weather patterns, grasping probabilities, knowing local conditions, and having alternative options. Preparing for the worst with comprehensive storm preps is crucial. Access to up-to-date weather data via various technologies (VHF, SSB, Navtex, email, satellite images) is essential. Finally, a knowledgeable shore-based advisor with extensive ocean sailing experience is invaluable for guidance.