Preparing for Heavy Weather

Reading the Warning Signs

Heavy weather rarely arrives without warning. The barometer, the sky, the sea state, and the forecast all provide advance notice — often 12–24 hours ahead. The sailors who get caught are the ones who ignored the signals or didn't check.

Barometric pressure is the single most reliable onboard indicator. A falling barometer means deteriorating conditions. The rate of fall matters more than the absolute reading: a drop of 1–2 mb/hour is moderate and worth watching; a drop of 3+ mb/hour means a significant system is approaching fast. A rapid fall of 5+ mb/hour is a storm warning in itself.

Sky signs: High cirrus clouds moving in from the west or southwest often precede a warm front by 12–24 hours. A halo around the sun or moon (caused by ice crystals in cirrostratus) is a classic heavy weather precursor. Towering cumulus building rapidly in the afternoon suggests thunderstorms within hours.

Sea state changes: Long, low swells arriving from a direction different to the local wind indicate a distant storm sending energy your way. The swell may arrive 24–48 hours before the storm itself. If the swell period is long (12+ seconds between crests), the generating storm is large.

The forecast: Check marine weather forecasts at least twice daily on passage. NOAA Weather Radio, Navtex, SSB weatherfax, satellite phone GRIB downloads, and VHF weather channels all provide information. Cross-reference multiple sources — a single forecast can be wrong; three agreeing forecasts rarely are.

Pre-Storm Deck Preparation

Once you've decided that heavy weather is likely, the deck preparation should begin immediately — while conditions are still manageable. Every task done in moderate conditions saves a dangerous job in 30 knots and steep seas.

Secure everything on deck. Anything that isn't permanently attached can become a projectile or go overboard. Dinghy painter doubled and checked. Liferaft lashings confirmed. Jerry cans, fenders, and spare lines stowed below or lashed to pad-eyes. Winch handles in their holders. Cockpit cushions below.

Close and secure all hatches and ports. Every opening is a potential flooding point. Dorade vents should have their cap covers fitted or the vent boxes sealed. Forehatch dogged shut — not just latched, but positively locked. Companionway washboards ready to insert fully.

Check the bilge pumps. Run both the electric and manual bilge pumps to confirm they work. Clear any debris from the strum boxes (intake filters). In heavy weather, water will get below — the question is how fast you can get it out.

Rig jacklines. Flat webbing jacklines run from the cockpit to the foredeck on both sides. They should be rigged tight enough that a person clipped to them with a short tether cannot reach the rail. Inspect the attachment points — pad-eyes and the jackline hardware itself.

Reef early. If you think you might need a reef in an hour, put it in now. Reefing in moderate conditions takes five minutes. Reefing in 35 knots with a flogging sail takes twenty minutes and risks injury.

Crew Briefing and Watch Planning

Before the weather arrives, the entire crew must know the plan. A crew briefed in advance operates calmly; a crew surprised by conditions panics.

The heavy weather briefing should cover: What weather is expected and when. What sail plan will be used. What the watch schedule will be. Where the safety equipment is (harnesses, tethers, flares, EPIRB). What the emergency procedures are (MOB, flooding, dismasting). Who does what if the skipper is incapacitated.

Watch schedules in heavy weather should be shorter than normal. Four-hour watches in calm conditions become two-hour watches in heavy weather — fatigue accumulates far faster when the crew is braced, cold, wet, and stressed. The off-watch crew must sleep, eat, and stay warm. A crew that has been awake for 36 hours makes catastrophic decisions.

Assign specific roles. The helmsman steers. The watch leader monitors weather, sail trim, and navigation. The standby crew is dressed and ready to come on deck within 60 seconds. Everyone knows who is responsible for what before it becomes difficult to communicate over the noise.

Pre-cook hot food. Once the boat is in heavy weather, cooking becomes difficult and dangerous. A thermos of hot soup, pre-made sandwiches, and easy-to-eat snacks should be prepared before the weather arrives. Dehydration and low blood sugar make seasickness worse and impair judgment.

The Shelter-or-Ride-It-Out Decision

The most consequential decision in heavy weather sailing is made before the weather arrives: do you seek shelter or ride it out at sea?

Arguments for seeking shelter: If a safe harbor is within reach before conditions deteriorate, going in is almost always the right call. A boat in a well-protected harbor with good holding ground is safer than any boat at sea in a storm. The key qualifier is 'before conditions deteriorate' — running for shelter in a full gale, entering an unfamiliar harbor in poor visibility, or crossing a bar in heavy surf are all far more dangerous than staying at sea.

Arguments for staying at sea: If you have sea room — open water to leeward with no coast to be driven onto — staying at sea in a well-found boat is a viable and often safer option than attempting to enter a harbor in deteriorating conditions. Offshore, the dangers are waves and wind; near shore, the dangers include rocks, shoals, breaking surf, and other vessels. Many of the worst disasters in sailing history involved boats that ran for shelter too late.

The decision framework: (1) How much time before conditions deteriorate? (2) Can I reach a safe harbor in that time? (3) Is the approach to that harbor safe in the forecast conditions? (4) Do I have adequate sea room if I stay out? If any of questions 2 or 3 are 'no', stay at sea. If question 4 is 'no', you must seek shelter — early.

The worst option is indecision. Boats that neither commit to shelter nor commit to sea-room often end up on a lee shore with no good options. Make the decision early, commit fully, and execute.