2.13 Storm Warnings & Heavy-Weather Handling

Storm Warnings and Heavy-Weather Handling

When heavy weather is forecast, the Weather Service and the Coast Guard advertise it two ways: by the wind ranges in a broadcast advisory, and historically by visual display signals flown at coastal stations. You must recognize both.

Coastal Warning Display signals

The Coastal Warning Display (CWD) system uses daytime flags/pennants and nighttime lights. The National Weather Service formally retired the program, but the Coast Guard re-established displays at selected small-boat stations, and the signals remain standard exam material:

Memory hook: pennants for the lighter warnings, square black-centered flags for storm and hurricane; one = the lesser step, two = the next step up. The signals are displayed from about one hour before sunrise to one hour after sunset (with lights at night).

Reading the water and sky

Do not wait for the flag. A falling barometer, a backing or freshening wind, a hard line of dark cloud, and a confused or building sea all say heavy weather is on the way. Get ahead of it while you still have sea room and daylight.

Preparing the vessel

Before the weather hits:

• Get PFDs on everyone, especially passengers, and brief them on what is coming and what to do.
• Secure all loose gear; close hatches, ports and vents to keep water out and prevent downflooding.
• Reduce speed, and move crew and passengers low and near the centerline to lower the vessel's center of gravity and improve stability.
• Fix your position and know where deep water, shelter, and the nearest safe harbor lie while you still can.
• Check that the bilge pumps work and that fuel and battery are sound - you may be at it for hours.

Handling the seas

The heart of small-vessel storm tactics is how you take the seas:

• Take them on the bow at roughly a 45-degree angle - not straight on (which pounds the hull) and never on the beam.
• Never lie in the trough (beam-to the seas); a large beam wave is exactly what rolls a small boat over.
• Slow down so the bow does not bury and the hull does not slam as it drops off a crest.
• When running before a sea, watch for broaching (the stern thrown sideways and the boat slewed beam-to) and for burying the bow in the wave ahead; ease speed and steer to keep the stern square to the seas.
• If you can no longer make way, heave to (hold the bow up to the seas under minimal power) or stream a sea anchor off the bow, or a drogue off the stern, to hold the boat's attitude and slow the drift.

There are three classic ways to ride out a blow, and the right one depends on your boat and your sea room. Running off (steering downwind, often trailing a drogue to prevent broaching and control speed) puts the seas on the stern and eases the motion, but needs plenty of sea room to leeward. Heaving to holds the bow up near the seas and lets the boat make slow, controlled headway or lie nearly stopped - good for resting the crew. Lying ahull (no power, no sail, drifting beam-to) is generally the worst option for a small vessel because it exposes the beam to breaking seas. Whatever you choose, commit early: it is far easier to set up storm tactics before the sea builds than in the middle of it.

If you take another boat in tow, rig a bridle to spread the load, keep the towline long enough to let both boats ride the same part of a wave, and watch for shock-loading as the line snaps taut.

Anchoring and crossing a bar

If you must ride it out at anchor, veer plenty of scope (7:1 or more, more in a blow), use a snubber, and stand an anchor watch against dragging. But the single most dangerous place for a small boat in heavy weather is a breaking inlet or bar: an ebb current running out against an onshore swell steepens and breaks the seas. If you must cross, time the sets, ride the back of a wave, keep power on for steerage, and never let a breaking crest catch you on the beam. When in doubt, wait for slack or better conditions offshore rather than commit to a breaking inlet with passengers aboard.