Preparing for a Storm When You're in Dock

Why act early

A forecast of strong wind or a named storm is not the time to invent a plan. Most boats that survive dockside storms do so because someone acted early: longer lines, less windage, working bilge pumps, and a clear decision about whether anyone stays aboard.

This guide is for boats already in dock (marina slip, quay, or floating pontoon).

First principle: people before boats

Experienced cruisers who have lived through typhoons and hurricanes repeat the same point: prepare the boat thoroughly, then get off if the risk is serious. You can replace gear; you cannot replace a crew. Follow marina evacuation orders. If you stay aboard for a lesser blow, never go on deck in unsafe wind without a harness and a spotter.

Why dock prep is about force, not "more rope"

Windage (side area to the wind)

Wind pressure rises fast with speed. Teaching texts often use a rule-of-thumb like this for illustration: at about 60 knots (Beaufort 11), pressure can be on the order of ~17–18 kg per square metre of exposed area. For a roughly 36 ft monohull, total windage (hull, cabin, mast, rigging) might be around ~55 m² beam-on versus ~32 m² head-to-wind—so the sideways load can be hundreds of kilograms higher than pointing into the wind. Exact numbers vary by boat; the lesson for dock prep is simple:

• Point the bow into the expected wind/waves when you can choose orientation.
• Strip windage (sails, covers, dinghy, loose canvas) so the boat is not a sail against the dock.

Surge, buoyancy, and sudden loads

Even without wind, rising and falling water plus waves create huge vertical and shock loads. At the dock that translates to:

• Lines that are too short will snatch or snap as the tide/surge rises.
• Lines that are too tight with no stretch will transfer every impact into cleats and hull fittings.
• Wind against current (or against a fixed dock) can create violent yaw and shock—think in tonnes of peak load in extreme cases, not tens of kilos.

Chain and stretchy nylon behave differently under shock: stiff setups peak high; arrangements with elasticity and weight hanging in the catenary (where appropriate) reduce peak load. At a dock you usually use nylon dock lines + snubbers, not bare wire.

Before the storm: marina and slip check

1. Ask the marina — Must boats evacuate? Are there designated storm berths or mangrove/hurricane-hole options?
2. Structure — Are piles, cleats, and pontoons sound? Floating docks can lift off piles in extreme surge; fixed docks can punch hulls if freeboard disappears.
3. Neighbours — A poorly secured boat next door is a hazard to you. Coordinate early.
4. Orientation — Prefer bow into wind/waves; avoid presenting the beam to the fetch if you have a choice.

Lines: build a "spider web"

Goal: keep the boat centred in the slip, free to rise with surge, without slamming the pontoon or the piles.

• Double (or triple) up breast lines, bow, and stern.
• Add spring lines (forward and aft) so the boat cannot surge fore-and-aft into the dock.
• Use cross-ties where the slip layout allows, so loads share across both sides.
• Prefer tying to pilings as well as (or instead of) only dock cleats—cleats and finger pontoons fail more often than piles.
• Lines should be long enough for surge (guidance often heard: on the order of boat length for key storm lines—adjust to your slip). Short lines = snatch loads.
• Spread load across many strong points; do not hang everything on one cleat. Confirm cleats have proper backing plates.
• Add snubbers / shock absorbers on primary lines.
• Fit chafe gear everywhere a line crosses a fairlead, pile, or rail (old fire hose, leather, dedicated chafe sleeves). Chafe is a top reason lines fail mid-storm.
• Have spare lines ready on deck or in the cockpit locker.

Liveaboard practice often looks extreme on purpose: a dozen lines, spider-webbed to piles, is normal for named storms—not overkill.

Fenders and contact

• Deploy many fenders, including oversized ones, covering contact zones with the pontoon and neighbours.
• Consider fender boards if your marina uses exposed piles.
• Check that fenders stay in place as the boat rises and falls.

Reduce windage and secure the deck

Strip or stow anything that acts like a sail or can tear free:

• Unbend or tightly furl and remove sails when practical; cover and lash if they must stay.
• Take down bimini, dodger canvas, cockpit enclosures when you can store them.
• Secure or remove dinghy, solar panels, life rings, cockpit cushions, loose gear.
• Lash the boom; arrange halyards so they do not flog for hours.
• Close and dog hatches; consider blanking dorades/vents if green water is likely.
• Stow below; remove valuables, documents, electronics, meds, and portable fuel if you are leaving the boat.

Systems that sink boats in marinas

Many marina losses in storms are mundane: dead batteries and failed bilge pumps, not dramatic dock collapses.

• Charge batteries fully; assume shore power will fail.
• Test automatic and manual bilge pumps; clear debris; keep paper and debris from clogging strainers.
• Know seacock positions; follow your boat's storm checklist (do not blindly close everything if it conflicts with bilge or engine needs—know your boat).
• Fuel for a generator if you rely on one; spare dry clothes sealed in bags if anyone remains aboard.

Surge planning

• Estimate extra water height (storm surge + tide + waves).
• On floating docks, lines to fixed piles may need length and adjustment so the dock can rise without hanging the boat or tearing fittings.
• On fixed docks, watch for pilings punching the hull if freeboard drops—extra fenders and careful positioning matter.
• If surge risk is extreme, discuss haul-out or relocation with the marina early (yards can book out).

Should you stay aboard?

Astrolabe Sailing's summary of advice from cruisers who faced Typhoon Haiyan is blunt: in port, do everything you can for the boat, then get off—it is not worth risking your life to "save" it in extreme conditions.

Quick checklist (dock)

• Marina policy / evacuation plan known
• Bow into wind/waves if possible
• Doubled lines + springs + cross-ties; loads on piles
• Chafe gear + snubbers
• Extra fenders
• Sails/canvas/dinghy windage removed or lashed
• Hatches secured; deck clear
• Bilge pumps + batteries verified; shore power assumed lost
• Spares: lines, fenders, flashlights, dry bags
• People: leave if ordered or if risk is high

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