Before a crossing, every detail counts. Rigging, engine, electronics, safety: a detailed checklist to prepare your boat thoroughly.
Summary
A crossing should never be improvised. Even on a boat that is considered reliable, the majority of accidents at sea are linked to simple failures, which can often be detected before departure. Neglected rigging, clogged fuel lines, worn-out batteries, or poorly configured electronics are among the recurring causes of abandonment or diversion. Preparing a boat for a crossing, whether it is a challenging coastal or offshore voyage, involves methodically checking each critical system, point by point, without relying on appearances. This checklist is not theoretical. It is based on concrete feedback, sea rescue statistics, and the practices of professional sailors. The goal is not to achieve zero risk, which does not exist, but to drastically reduce the probability of avoidable breakdowns and increase the ability of the boat and crew to manage an incident far from any immediate assistance.
Rigging, the leading cause of abandonment in offshore sailing
Checking the standing rigging
The standing rigging is constantly working. It wears out silently. Before a crossing, no cable, rod, or crimp should be assumed to be sound.
Each component must be inspected visually and mechanically. Critical points are the crimping, areas near the end fittings, and deck passages. The presence of broken wires, cracks, or corrosion is an immediate warning sign. A shroud that is more than ten years old, even if it has no visible defects, should be considered suspect for a long crossing.
Turnbuckles must turn freely, without any sticking. Pins must be secured with cotter pins or wire. A seized turnbuckle is a turnbuckle that cannot be adjusted or removed in an emergency.
Checking the running rigging
The running rigging is subject to dynamic stress. Halyards, sheets, and tows must be inspected along their entire length. Areas that pass through winches, blockers, and sheaves are a priority.
A halyard with a flat spot, an open sheath, or localized hardening must be replaced. During a crossing, the loss of a mainsail halyard can immobilize a boat. It is strongly recommended to carry at least one spare halyard ready to be attached.
Pulleys must turn freely. A stuck pulley quickly wears out a rope and can fail without warning under load.
The engine, the modern sailor’s life insurance
The fuel system, often underestimated
Most engine failures at sea are related to fuel. Before departure, drain the decanters, replace the filters if their age is uncertain, and purge any water in the tank.
Hoses must be flexible and free of cracks. Clamps must be tight and in good condition. A diesel leak at the dock often becomes a serious breakdown at sea.
It is essential to take at least two sets of engine filters on board, as well as the tools needed to change them while sailing.
The cooling system and transmission
The water pump turbine must be recent. A turbine that is more than a year old on a heavily used engine is an unnecessary risk. Check that the spare turbine is on board.
The water hoses must be inspected, as well as the exhaust elbow, a critical part on marine diesel engines. A corroded elbow can puncture without warning.
On the transmission side, the shaft, stuffing box, and rotary joint must be checked. A slow leak at the dock can become uncontrollable at high speeds.
Electricity and batteries, the lifeblood of modern warfare
The actual capacity of the batteries
Before a crossing, it is important to know the actual usable capacity of the battery bank, not its theoretical capacity. A five-year-old battery may have lost more than 30% of its initial capacity.
It is essential to check the voltages when the batteries are empty and when they are under load. A rapid drop in voltage under load is a sign of a tired battery. An electrical failure during a crossing often leads to a loss of navigation and communication.
Connections must be clean, tight, and protected. Oxidation is the silent enemy of electricity on board.
Charging methods
Alternators, solar panels, hydrogenerators, and shore power chargers must be tested individually. It is common for alternators to no longer charge properly at low speeds.
Actual charging currents must be checked, rather than relying solely on indicator lights. A faulty regulator can overcharge or undercharge the batteries.
Navigation electronics, only useful if you know how to use them
Essential instruments
Before departure, each instrument must be tested in real conditions. The GPS must display a consistent position. The log and depth sounder must give plausible values. A faulty sensor is often ignored until the critical moment.
It is recommended to have at least two independent means of positioning, for example a main GPS and a tablet with offline mapping.
The autopilot, a key element during the crossing
The autopilot is the most heavily used piece of equipment. It must be tested under load, under engine power and under sail. An autopilot that struggles to hold a course at 6 knots can completely fail at 8 knots in rough seas.
Mechanical fastenings, arms, jacks, and lines must be inspected. A mechanical weakness is often more critical than an electronic fault.
Safety, beyond regulatory compliance
Personal safety equipment
Each life jacket must be checked. CO₂ cartridges must be full. Automatic release systems must be up to date. A worn or too short lanyard must be replaced.
It is advisable to require life jackets to be worn at night and in rough seas, without question.
Collective equipment
The life raft must be serviced and accessible. Its service date must be checked. There must be a sufficient number of flares, and they must not be expired.
The manual bilge pump must be in working order. Many pumps are seized due to lack of use. They must be tested in real conditions.
The hull, appendages, and structural weak points
The hull and through-hull fittings
Each through-hull fitting must be operated before departure. A stuck valve is a useless valve. Double clamps must be tight and in good condition.
Porthole and panel seals must be inspected. A slow water leak can become critical over several days at sea.
The rudder and appendages
The rudder play must be checked. Excessive play is a warning sign. The anodes must be in place and thick enough for the planned duration of the voyage.
Spare parts and tools, true autonomy
A crossing requires critical parts to be taken on board: filters, belts, turbine, bulbs, fuses, simple sensors. The tools must allow you to actually dismantle what you plan to repair.
A good indicator is simple: if a breakdown comes to mind, you must have the means to deal with it on board.
Human preparation, often overlooked
A well-prepared boat with an exhausted crew is still a vulnerable boat. Sleep, watch schedules, and the distribution of roles must be planned in advance.
Each crew member must know how to start the engine, use the VHF, operate the autopilot, and locate safety equipment. In a difficult situation, improvisation can be costly.
Long-distance sailing begins at the dock
Preparing for a crossing is not an administrative formality. It is methodical work, sometimes thankless, but always rewarding. Miles traveled without incident are almost always the result of hours spent checking, testing, and correcting before departure.
The sea does not forgive technical shortcomings. It reveals weaknesses with relentless precision. A rigorous checklist does not make you invincible, but it transforms a lucky sailor into a prepared sailor. And when crossing, this difference is rarely abstract.
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