Most collisions at sea happen at night, and most of them involve something the watchkeeper never saw: an unlit wooden fishing boat, a half-submerged container, a net buoy, a channel marker gone dark. Radar helps, but small wooden and fiberglass targets return weak echoes, and the most dangerous objects sit low in the water. The human eye, even with night vision habits and a spotlight, is the weakest sensor on the bridge.
This case looks at how a coastal workboat operator added dual-spectrum thermal-visible vision to its fleet’s bridges — and what it changed for night transits and crew safety.
Project Background
In 2024, the marine operations manager of a workboat company on the southeast China coast — eleven vessels running crew transfers, survey support, and supply runs to offshore aquaculture zones and a wind farm under construction — reviewed two years of incident reports. The pattern was uncomfortable: three near-misses with unlit small craft inside twelve months, a night transit aborted after floating debris damaged a propeller, and one man-overboard drill that showed how slowly a crew could relocate a person in the water at night even in calm conditions. The fleet’s night toolkit was the industry default: radar, AIS, a hand-held spotlight, and a searchlight on the larger vessels. Small wooden boats without AIS were effectively invisible until close aboard. The company funded a fleet trial: gyro-stabilized dual-spectrum thermal-visible camera systems on the wheelhouse tops of four vessels, with AI detection for navigation hazards and a dedicated man-overboard alarm mode.
Pain Points of the Traditional Approach
- Radar is blind to the targets that matter most at night. Small wooden and fiberglass boats, floating debris, and persons in the water return little or no usable echo — the classic radar hole in coastal night operations.
- AIS only sees cooperative targets. A vessel without a transponder — common among small coastal craft — simply does not exist on the AIS display.
- Searchlights illuminate a cone, not the sea. A spotlight checks one bearing at a time, destroys the crew’s night vision, and announces the vessel’s position and attention.
- Man overboard at night is a race nobody wins unaided. Once a person is in dark water, visual relocation depends on luck, sea state, and how fast the alarm was raised — minutes decide outcomes.
The Thermal Imaging Solution
Each fitted vessel carries a gyro-stabilized dual-spectrum unit above the wheelhouse: a 640×512 LWIR thermal channel paired with a low-light visible camera, feeding a display at the helm. The thermal channel renders the night sea as a readable scene — unlit boats, buoys, floating debris, and swimmers all stand out against the water by their temperature difference, in total darkness and through haze that defeats the eye.
Edge analytics run two watch modes. In navigation mode, the system detects and tracks heat signatures ahead and to the sides, flagging closing targets with bearing and range cues so the watchkeeper can alter early instead of late. In man-overboard mode, armed whenever crew work on deck at night, the camera sweeps the water around the vessel and raises an immediate alarm on a person-shaped thermal signature in the water, slewing to hold the contact so the helm sees exactly where to steer. Because the system is fully passive, it adds nothing to the vessel’s own signature and never blinds the crew with light.
What the Thermal Solution Changed
- Unlit craft became routine detections, not surprises. Across the first operating season, the four fitted vessels logged dozens of night detections of non-AIS small craft at ranges that allowed early, gentle course alterations — no further near-miss reports.
- Debris strikes stopped. The thermal watch repeatedly picked up half-submerged logs and net material in time to avoid them; the following season recorded no propeller or hull damage on fitted vessels.
- Man-overboard response became a procedure instead of a search. In drills, the alarm-and-slew workflow put the helm’s eyes on the person in the water within seconds, and the time to return alongside was cut by more than half.
- The unlit-channel transit risk profile improved enough to matter to insurers. The fleet’s night-operation restrictions were relaxed for fitted vessels, adding usable working hours to every charter.
Module Selection Notes
Marine duty demands a dual-spectrum unit with sealed, corrosion-resistant housings, gyro stabilization for a moving deck, and thermal sensitivity that picks a person’s head out of wave clutter. The FUSION LV0625A visible + LWIR dual-spectrum EO/IR module is the fleet-fit core for this application; where automatic target tracking is needed at the sensor, the NEXUS LV0619B EO/IR AI tracking module adds onboard AI. See the maritime application page for navigation and man-overboard deployment patterns.
Equipping a fleet for night operations or adding man-overboard detection? Talk to our engineers about dual-spectrum selection, stabilization, and bridge integration.
