Offshore passage planning: the checklist that matters

Passage planning guides usually stop at the weather routing. The things that actually decide whether a crossing is pleasant are more mundane: who stands which watch, how much water you carry, and whether the crew know their man-overboard jobs before they need them.

The weather window, honestly assessed

Pick the window for the crew you have, not the boat you have. A forty-foot cruiser will take almost anything; a crew of four with two first-timers will not. Look at the first seventy-two hours in detail — that is when seasickness, sleep debt and doubt all peak at once — and be more conservative about the departure than about the middle of the passage.

Write down the conditions that would make you turn back or divert, before you leave, while you are still capable of being sensible about it.

Crew and watch planning

Decide the watch system before departure, not on the first evening. It affects provisioning, berth allocation and who sleeps where, and changing it at sea costs you a full day of everybody being confused.

Set out who leads each watch, who must not be alone on deck at night, and who is seasick-prone and therefore needs waking earlier. Then check what the rota does to the person who comes off worst — see watch systems compared and crew fatigue.

Water, food and fuel

Three litres of drinking water per person per day is the working figure, plus a margin of at least twenty per cent, plus an untouched reserve for a slow landfall. Water is the one to be generous about; everything else can be eaten cold.

Plan fresh food for about six days and dry or tinned after that, and cook the first two days' meals before departure — nobody wants to cook on day one, and nobody should have to.

The safety brief nobody enjoys

Do it alongside, in daylight, with everybody on deck and nobody in a hurry. Lifejackets fitted and lights tested by name. Tethers and where to clip. Flares, liferaft, grab bag, EPIRB, seacocks, bilge pumps, fire extinguishers, engine kill. Then the awkward ones: what happens if the skipper is incapacitated, and who takes over.

Written cards per person work better than a speech, because on day four nobody remembers a speech.

Documents and records

Ship’s papers, insurance, crew list with passport details and next of kin, and clearance requirements for where you are going. If the boat is commercially operated, or the crew are paid, you will also need rest-hours records — see hours of rest.

Start the log at departure and keep it properly. It is evidence, it is a navigation tool if the electronics fail, and it is the only thing that will tell you what actually happened on day six.

The jobs nobody remembers until day three

Preventers rigged both sides before the first night, not during it. A jackline that reaches the foredeck. Lee cloths on the sea berths. A torch in every berth. Somewhere to put wet oilskins that is not the saloon. A bucket with a lanyard. And the courtesy flag, which you will not find in the dark at anchor.

Route, waypoints and the decision points

A route is not a line on a chart, it is a series of decisions with dates attached. Mark the points where you commit — where you can no longer divert to the harbour you passed, where you must be by a certain date to keep a weather window, where you cross a shipping lane and want to be awake and sober about it.

For the classic trade-wind crossing that means the decision to go south before turning west, the point where you stop being able to reach the Cape Verdes, and the approach to the far side where landfall in darkness becomes a real question. Write them down with a date beside each and the crew will understand the passage rather than just following it.

Gear, spares and the failures that end passages

Passages are ended by a small number of failures, in a predictable order: autopilot, standing or running rigging, steering, watermaker, engine cooling, and chafe. Chafe deserves its own line because it is the only one that is entirely preventable and the one most likely to happen on a long downwind run.

Carry spares for what you cannot improvise: autopilot ram or drive belt, impellers, filters, halyard and sheet lengths, a bolt-croppers-and-spare-shackles kit for the rig, and enough sail-repair material to make a tear survivable. Then walk the boat every morning looking specifically at anything that moves against anything else.

Communications and weather at sea

Decide before departure how you will receive weather and how often, and tell the crew — an uninformed crew invents forecasts. Satellite messengers and small terminals now make daily GRIB files and a routing update routine rather than exceptional, but the discipline matters more than the equipment: same time each day, same person, written on the log page rather than remembered.

Agree what you will send home and how often, because a family expecting a nightly message will call out a rescue coordination centre over a flat battery. One scheduled message a day, and a stated rule that silence for forty-eight hours means nothing more than a technical problem, saves an enormous amount of trouble ashore.

Costs, clearance and the paperwork of arriving

Clearance requirements change and are enforced unevenly, so check the current position for your destination rather than relying on a cruising guide printed three years ago. Have crew passport details, a printed crew list, insurance documents, ship’s registration and any radio licence in one folder, and a scan of all of it somewhere reachable if the folder gets wet.

Budget for arrival as well as passage: berthing, clearance fees, agents where they are mandatory, and flights home for crew who are leaving. A crossing on a shoestring that arrives with no money for a berth is not a saving.

Questions skippers ask