Compact Offshore Preparation Guide for Cruising Catamarans

Extended bluewater passages place continuous stress on vessel systems and crew. This guide condenses essential checks, spare parts and routines into a compact plan designed to keep systems reliable and risks manageable while offshore.

Begin with meticulous pre-departure planning and paperwork. Plan your route with waypoints, alternates and weather windows; leave no less than two alternates per critical waypoint. Calculate expected daily mileage and identify opportunistic bunkering options. Gather vessel registration and flag papers, crew passports and visas, insurance certificates that confirm bluewater and third-party liability coverage, radio license, ship’s papers and destination permits. Stock a fully equipped offshore medical kit with prescription meds, antibiotics, sutures and, if trained, IV fluids, create a written medical plan, and ensure at least one crew member is trained in first aid and sea-sick prevention.

Systems and engineering work reduces the chance of failures. Service engines with full oil and filter changes, fuel filter replacements and cooling system checks, inspect belts and mounts, and run engines at cruising RPM for extended tests. Carry spare fuel filters, belts and critical consumables. Inspect propulsion seals and props, verify thrusters if fitted, and perform a full capacity check on house and start batteries. Verify alternator and charging capacity to recharge daily loads and confirm solar arrays are clean and connections secure. Test all navigation electronics, nav lights, bilge pumps and domestic circuits, label circuits and create a simple electrical diagram and troubleshooting sheet.

Water, sanitation and fuel planning matter. Service the watermaker and carry a membrane spare for long passages, check pumps and plumbing, and plan for greater than 1.5 to 2 liters of water per person per day with redundancy. Calculate fuel consumption and add contingency reserves of 20 to 30 percent beyond planned use.

Safety and survival equipment must be current and practiced. Service liferafts within their certificate period and rehearse deployment, test and register EPIRB and PLBs, confirm battery expiry dates, and ensure communications include satellite options such as Iridium GO! or satellite phone, SSB and VHF DSC with programmed numbers. Maintain a posted fire-fighting plan and practice MOB and abandon-ship drills at sea.

Rigging, sails and deck gear need careful inspection and spares. Check standing rigging tension, chainplates, spreaders and shroud terminals, service running rigging and winches, and carry a small splicing kit, extra shackles and blocks. Prepare a heavy-weather sail plan including a storm trysail or storm jib.

Practical onboard living items include menu planning with non-perishable backups and watermaker redundancy, a critical-spares kit with items such as fuel filters, impellers, alternator belt, starter solenoid, raw-water pump and refrigeration parts, and tools including a multimeter and wiring diagram. Seal galley and stores for vermin control.

Short pre-departure checks within 24 to 72 hours include oil, filters and belts; full tanks and tested transfer pumps; battery state-of-charge and load tests; sail and rig checks; liferaft and EPIRB service and testing; functioning satellite comms; stocked provisions and labeled spares; and physical and digital copies of documents and insurance. Discipline, redundancy and practiced crew routines provide the best defense against equipment-failure cascades offshore.