Subsea Lighting for ROVs: Imenco, SubC, and DeepSea Power Compared

Subsea lighting is one of the most discussed and least systematically understood topics in ROV operations. Pilots spend years developing intuitions about which light arrangement produces usable video in turbid water, which color temperature makes corrosion visible on steel, and why two lights of nominally the same wattage can produce dramatically different results on camera. This guide covers the technology evolution from HID to LED, the three dominant manufacturers in the work-class ROV segment, and the practical selection criteria that matter when specifying or operating subsea lighting systems.

HID to LED: A Technology Transition

High-intensity discharge (HID) lamps — predominantly 150W and 250W metal halide units — were the standard subsea lighting technology from the 1980s through the early 2000s. HID subsea lights produced high lumen outputs (a 250W HID unit produces roughly 20,000–25,000 lumens) with good color rendering, but they required warm-up time of 90–120 seconds to full output, generated significant heat that stressed pressure housing seals, had limited lamp life of 500–1,500 hours, and were sensitive to voltage transients. The transition to LED lighting that accelerated from approximately 2010 onward addressed most of these limitations: LED lights reach full output instantaneously, generate less waste heat, have service lives of 30,000–50,000 hours, and are more tolerant of voltage variation. A modern 100W LED subsea light produces 12,000–18,000 lumens, matching a 150W HID system while consuming less power and generating less heat.

Imenco LED-6000 and Shark Series

• Imenco is a Norwegian subsea equipment manufacturer whose LED subsea lights are widely used on North Sea work-class ROVs; the LED-6000 series is their mid-range work light producing approximately 6,000 lumens from a 50W input
• The Shark series covers higher-output requirements — the Shark 12000 delivers 12,000 lumens at 100W; the Shark 24000 produces 24,000 lumens at 200W using a multi-LED array behind a single polycarbonate lens
• Depth ratings in the Imenco range extend to 4,000m for the standard series and 6,000m for deep-rated variants; the pressure housing is titanium with glass or sapphire lens options for abrasive environments
• Beam angle on standard LED-6000 is 60 degrees flood — appropriate for general video work; Imenco offers 30-degree spot and 90-degree ultra-wide flood versions for specific applications
• Connector interface: SubConn circular wet-mate connectors standard; Seanet wet-mate optional; the LED driver circuitry is internal and accepts 24–48V DC supply directly from the ROV power system
• Color temperature: 6,000K (daylight white) standard; 5,000K warm white available on request — the 6,000K output is preferred for video work as it produces neutral whites and accurate color rendering on steel and concrete structures

SubC Aquorea LED System

SubC Imaging — a Canadian company better known for their subsea camera systems — produces the Aquorea LED light series designed for integration with their camera platforms. The Aquorea uses high-CRI (Color Rendering Index greater than 90) LED arrays specifically selected to support accurate color video: a high CRI light source renders reds, greens, and yellows at their true values, which matters when inspecting coating condition, identifying marine growth species, or assessing corrosion products on steel. The Aquorea is available in 5,000, 10,000, and 20,000 lumen configurations with a color temperature of 5,600K. The 20,000 lumen unit draws 175W and is designed for paired operation flanking a main camera. SubC integrates their lighting and camera control into a single electronic interface that allows the pilot to adjust light intensity and camera exposure from the surface control system simultaneously.

DeepSea Power and Light Systems

DeepSea Power & Light (DSPL), based in San Diego, is one of the longest-established subsea lighting manufacturers and has supplied lights for manned submersibles, unmanned ROVs, and scientific platforms since the 1980s. Their LED product line includes the Multi-SeaLite and Rayfin camera-integrated systems. The Multi-SeaLite produces up to 30,000 lumens from a 250W LED array and is depth-rated to 6,000m. DSPL uses an anodized aluminum housing in the standard configuration and offers titanium for deep or corrosive applications. A distinguishing feature of DSPL products is their optical design precision — DSPL uses acrylic lenses machined to tight tolerances that produce well-defined beam profiles with minimal scatter at the edges, which reduces backscatter in turbid water compared to simple diffuser-type lenses. The Rayfin is a camera-plus-light integrated system with the LED array built into the camera housing alongside the imaging sensor, ensuring geometric alignment between the illumination cone and the camera field of view.

Beam Angle Selection: Spot vs Flood

• Flood beams (60–90 degrees) are the default for general ROV survey and inspection: wide coverage reduces sharp shadows, illuminates a broad field of view, and is forgiving when the pilot adjusts camera zoom or vehicle position
• Spot beams (15–30 degrees) concentrate light energy on a small area, increasing apparent brightness within the spot — useful for long-range illumination at 10–15m range in clear water or for detail inspection where the camera is zoomed to a small area
• In turbid or particle-laden water, spot beams can make backscatter worse by concentrating the light-to-camera return path through the water column; angled flood lights positioned outboard of center reduce backscatter by illuminating the subject from a direction that does not return directly to the camera lens
• For pipeline and cable tracking, a pair of spot lights aimed slightly downward at 30-degree angles on either side of the vehicle creates a triangle of illumination on the seabed that is effective for tracking along a structure at 3–5m altitude
• Paired flood-plus-spot configurations (one flood for ambient illumination, one spot for detail) allow the pilot to switch between overview and detail modes without repositioning the vehicle — common on larger work-class vehicles with four or more light positions

Color Temperature for Video Work

Color temperature selection affects what subsea video looks like and what information it can convey. At 5,500–6,000K (daylight white), video of steel structures shows accurate rust orange, true black on marine growth, and neutral grey on clean steel — colors that match client expectations for inspection deliverables. At lower color temperatures (3,500–4,500K warm white), whites appear yellow and blues shift green, which distorts color-based condition assessment. For biological surveys, a slightly lower color temperature around 5,000K is sometimes preferred to reduce the sterile clinical appearance that high color-temperature lights give to coral and invertebrate subjects. The camera's white balance setting interacts with the light source color temperature: always confirm the light color temperature and set the camera white balance accordingly before starting a survey dive.

Connector Types, Depth Ratings, and Maintenance

• SubConn circular wet-mate connectors (4-pin and 8-pin versions) are the most common interface on work-class ROV lights — they mate reliably at depth and are available from multiple suppliers; always flush connector faces with fresh water and inspect O-ring seats before mating at depth
• Seanet wet-mate connectors are preferred by some operators for their higher current rating (up to 30A vs 15A for SubConn 4-pin) — relevant for high-power 200W+ LED units
• Depth ratings are typically stated at 3,000m, 4,000m, or 6,000m; verify that your light's depth rating exceeds the operational depth plus a 20% safety margin
• Lens cleaning: polycarbonate lenses accumulate biological fouling and mineral deposits in service; clean with a soft cloth and mild detergent — not abrasive cleaners that scratch the lens surface and permanently reduce light transmission; inspect the lens for crazing or delamination of the anti-reflection coating
• Potting repair: LED subsea lights use epoxy potting compound to seal the LED array and driver electronics; potting cracks are a serious failure mode that allows water ingress; inspect for cracks or delamination at the potting surface visible through the lens, particularly at the housing edge
• Record light operating hours on each unit — LEDs degrade in output over time (typically 10–20% output reduction at 10,000 hours); replacing a light that has lost 20% output on a video survey improves deliverable quality at minimal cost