Serious light from one compact fitting
At the helm after sunset, clear information comes before theatre. I want to see the stern, understand which light mode is active and know that the electrical load has been planned before anybody reaches for a switch. The Bluefin LED Piranha P24 brings an unusually direct proposition: 12,000 fixture lumens, cobalt blue and diamond white from one compact surface-mounted fitting, priced at £666 including VAT.
This is a light-emitting diode (LED) fitting with a 130-millimetre diameter, an 18.5-millimetre profile and an aluminium body, backed by Registro Italiano Navale (RINA) maritime type approval. It runs on 12- or 24-volt systems, drawing 10 amps at 12 volts or 5 amps at 24 volts. A simple power toggle selects colour or strobe. Flood Marine also lists control from a multifunction display (MFD) or mobile device; I would specify that as a compatible controller-led installation and confirm the exact interface before the cable route and helm controls are finalised.
Bluefin LED Piranha P24 Dual Colour vs OceanLED X16 Colours vs Hella Apelo A2 vs Shadow-Caster SCM-10-EXT-CC
| Underwater light | Current price | Difference | Published output | Colour and control | Supply and maximum load | Mounting and body | Protection and stated use |
|---|---|---|---|---|---|---|---|
| Bluefin Piranha P24 dual colour | £666 | Reviewed model | 12,000 fixture lumens | Cobalt blue / diamond white; switch colour and strobe; compatible system control | 12 / 24 V; 10 A / 5 A | 130 mm aluminium surface mount; 18.5 mm profile; 18 mm cable hole | RINA type approved; active thermal, voltage, current and polarity protection; above/below waterline |
| OceanLED X16 Colours | £492 | £174 less | Up to 4,500 fixture lumens; 60° beam | Red, green, blue and white switching; OceanDMX app with optional control hardware | 9–32 V; 3.2 A at 12 V / 1.5 A at 24 V | Grilamid polymer surface mount; 12.5 mm cable hole; 3 m cable | Ingress Protection rating IP69K; above-water capable; two-year warranty |
| Hella Apelo A2 blue/white | £247 | £419 less | 3,000 white lumens; focused horizontal pattern | Blue / white, strobe and white Edge Light | 9–32 V; under 2.5 A at 12 V / 1.25 A at 24 V | 95 mm hard-anodised aluminium surface mount; 15 mm hole; 2.5 m cable | Ingress Protection ratings IP68 / IP69K; retailer limits this version to dry-stored hulls; five-year warranty |
| Shadow-Caster SCM-10-EXT-CC | £914 | £248 more | Up to 3,750 lumens; 120° beam | Ten red, green, blue and white (RGBW) LEDs; 12 switch colours or unlimited with Shadow-NET controller | 10–30 V; 42 W / 3.5 A at 12 V | 316 stainless steel; 254 × 61 × 13 mm; 20 ft cable | Ingress Protection rating IP68; gel-filled and thermally managed; three-year warranty |
Across the four, the P24 is the strongest overall purchase because its 12,000-lumen output is more than twice OceanLED’s published figure and more than three times the Hella or Shadow-Caster figures, yet it costs £248 less than Shadow-Caster. OceanLED and Hella reduce the entry price, while Shadow-Caster adds a broad colour palette, but none matches Bluefin’s combination of dual-colour usefulness, concentrated output, aluminium surface-mount construction, RINA approval and straightforward switch operation. I see £666 as the clearest route to serious white-and-blue illumination without making added control hardware the heart of the system.
Brightness with a purpose at the helm
Fixture lumens are the manufacturer’s output figure at the light, not a promise about what every transom will look like. Water clarity, mounting depth, hull colour, angle and the number of fittings all change the visible result. Even with that proper qualification, 12,000 is a substantial published figure from a 130-millimetre unit. I would expect the P24 to create a more authoritative pool of light than the lower-output alternatives when the installation is matched carefully to the hull.
Diamond white is the practical mode for checking the water immediately behind the boat, illuminating a boarding point or giving the stern a clean working light. Cobalt blue changes the atmosphere without forcing an owner into a full-colour controller on day one. The strobe option is selected through the same simple toggle sequence. I like that hierarchy: the basic control remains intelligible in the dark, while a more integrated helm or phone interface can be considered as the lighting system grows.
A compact fitting still needs a proper circuit
The surface-mount format keeps the hull work contained. Bluefin specifies one 18-millimetre cable-entry hole and three mounting screws, with the driver built into the fitting. That is much less invasive than a large through-hull body, though it still deserves accurate marking, suitable bedding and a cable run kept dry and protected on the inside. I would follow Bluefin’s template and installation manual rather than use the light itself as a drill guide.
The load is the important planning number. Ten amps on a 12-volt supply is significant for a single light; on 24 volts the stated draw halves to five amps. Cable size, fuse or breaker rating, switching capacity, voltage drop and the battery budget should all be calculated for the full run and the number of fittings. I see that demand as the electrical cost of the P24’s output. Once the circuit is designed around the published maximum, the helm control can remain calm and predictable.
Protection that earns confidence below the waterline
Bluefin builds in over-voltage, over-current and reverse-polarity protection, along with active thermal rollback. The last item matters because an underwater light can also be used above the waterline, where cooling conditions differ. The electronics can reduce output to manage temperature rather than relying on the operator to judge heat by eye. I value protections that work quietly behind the interface, particularly on a circuit exposed to charging voltages and long cable runs.
The aluminium body gives the P24 a compact, solid mounting face, and Bluefin states that it is suitable above or below the waterline and carries RINA maritime type approval. Hull material and isolation remain part of a competent installation, especially where dissimilar metals can meet. I would have the installer confirm compatibility, sealant and fastener choice for the exact transom. That care supports the product’s strengths and protects the boat around it.
Simple control now, useful growth later
A switch-controlled light is easy to understand because the power sequence moves between white, blue and strobe. There is little menu learning at the point when clear feedback matters. If the boat later adopts compatible lighting control, Flood’s listed MFD and mobile options give the P24 a route into a more coordinated system. I would confirm controller compatibility and available functions as a package, since the light itself should not be mistaken for a network gateway.
That distinction keeps expectations tidy. The P24 works as a powerful dual-colour fitting with ordinary switch logic, and control equipment can add the richer interface. OceanLED follows a similar optional-controller path but begins with far less published output. Shadow-Caster offers deeper colour choice at a higher price and lower lumen figure. Hella provides a compact dual-colour lamp, though the compared retailer limits its aluminium version to dry-stored hulls. Bluefin keeps the central benefit visible: a great deal of useful light from one low-profile unit.
Erin’s verdict
I would choose the Bluefin P24 when the brief is strong, clear stern illumination in white and blue, with a control sequence that remains understandable at night. The 12,000-lumen rating, 12- or 24-volt operation, protective electronics and small cable opening make a convincing system, provided the circuit and mounting are specified with the same care as the light.
My verdict gathers output, usability and future control into one confident choice. The P24 outshines the compared alternatives on the published figures, undercuts the most expensive one and leaves room for compatible helm or mobile control later. View the Bluefin LED Piranha P24 dual-colour light at Flood Marine.
About this review
I used Flood Marine’s live product page, Bluefin LED’s official product information, technical sheet and installation manual, official OceanLED, Hella marine and Shadow-Caster material, and the named UK retailer listings. Prices were checked on 14 September 2026. This is an editorial assessment rather than an instrumented performance, durability or sea test. I am Erin McKee, an independent reviewer, and this article was not written by Flood Marine Services.
