A visual signal does not just need to be bright. Its light has to reach the observer while the vessel is moving, which makes beam geometry one of the most important parts of the optical design.
Beam angle describes the spread of light from an optical system. Horizontal and vertical angles can be different, particularly where the designer wants broad coverage across the horizon without wasting as much energy above and below the useful viewing zone.
Concentrating light into a narrow angle can produce a very high peak candela figure. The drawback is that the user has to keep that narrow beam on the observer. That can be difficult from a small vessel that is pitching, rolling and yawing.
If the same available light is spread over a very wide area, more observers may fall within the beam but the intensity in any one direction falls. Optical design is therefore a balance rather than a race for the widest or narrowest possible beam.
At sea, the horizon is the main search plane. Wider horizontal coverage can help as the vessel changes heading, while a more controlled vertical spread concentrates output where surface vessels and low-level search assets are likely to see it.
UltraFlare Daylight uses a 45 degree horizontal display and 15 degree vertical display. The full-size unit has independently measured peak luminous intensity above 40,000 candela. The purpose of the optics is to combine useful angular coverage with strong directional intensity rather than simply producing an unrestricted glow.
In bright conditions, contrast is difficult to achieve. Concentrating useful output into a controlled viewing sector can help improve conspicuity, but real-world visibility still depends on background, weather and line of sight.
Read what candela means and our daylight visibility guide for the other parts of the picture.