Evidence to Preserve After a Boat or Ship Accident

The best evidence in a marine casualty case often exists for only a short time. Voyage data recorders run on a loop. Radio recordings are kept for limited periods. Phones get replaced. Logs get "cleaned up." By the time a lawsuit is filed, some of the most useful material may already be gone.

If you take one thing from this post, let it be this. Send a preservation letter in the first days, and name the specific sources you want kept.

Electronic sources

Voyage data recorder (VDR). Required on many ocean-going ships and larger passenger vessels. It can capture bridge audio, radar images, positions, heading, speed, rudder and engine orders, alarms, and VHF traffic. It is the closest thing a ship has to an aircraft's black box. It also records over itself. Older units may hold as little as twelve hours on a continuous loop. Newer standards require longer storage, but the clock is still running from the moment of the accident. The crew should save the data right away, and a qualified technician should download it.

AIS. Position, speed, course, and heading reports from the vessels involved and others nearby. Data can come from shore receivers, satellites, commercial providers, and government archives. Different sources have different gaps, so it is often worth pulling more than one.

ECDIS and radar. Electronic chart systems and radars may log tracks, settings, alarms, and screen captures. What was saved depends on the equipment and how it was set up.

Engine and alarm logs. Many vessels record engine orders, machinery alarms, and system faults automatically. In a loss-of-power or steering case, these are central.

Bridge and deck video. Increasingly common, especially on passenger vessels and at terminals. Video systems often overwrite quickly.

Radio recordings. VHF traffic recorded by the Coast Guard, vessel traffic services, port authorities, and sometimes the vessels themselves.

Phones and personal devices. Call, text, and data records for the people on watch. Carriers keep some records only for limited periods.

Small-boat electronics. GPS units, fish finders, and engine computers on recreational boats and jet skis can store tracks and speeds.

Paper and administrative sources

• Deck log, engine log, and bell book (the originals, not copies)
• Course recorder output where fitted
• Passage plan and pilot card
• Crew list, watch schedule, and rest-hour records
• Safety management system procedures and checklists in effect at the time
• Maintenance records for the equipment involved
• Training records for the people involved
• Coast Guard and NTSB reports, and the CG-2692

Conditions

Weather observations, tide and current data, and river gauge readings for the time and place. These are public and do not usually disappear, but pulling them early helps build the first timeline.

How to preserve it properly

How the data is collected matters as much as getting it. A VDR download done carelessly, or AIS data exported without its source information, invites a fight about reliability later. Good practice includes:

• Forensic downloads by technicians who know the equipment
• Documented chain of custody
• Recording the vessel's clock offsets, since equipment clocks rarely agree
• Photographing equipment settings before anything is changed
• Keeping the original files, not just printouts or screenshots

Why the expert should be involved early

A maritime expert who comes in during the first weeks can tell counsel which sources exist on that type of vessel, which ones overwrite fastest, and what to ask for by name. That is worth more than any opinion written later from an incomplete record. Once the data is gone, nobody can bring it back.

About the author

Captain Mitchell S. Stoller is a Master Mariner Unlimited, former Exxon tanker master, and former Los Angeles Harbor pilot. About Captain Stoller