1 - Compass rose legibility
The choice of compass rose is crucial to clear, precise reading of information. Three types of rose are available: flat, conical and cylindrical. The flat rose, ideal when the compass is below the helmsman's line of sight, offers excellent readability thanks to the magnifying glass effect created by the liquid. On the other hand, the conical or cylindrical rose, readable at eye level, is more versatile, allowing frontal reading. The choice will depend on the position of the compass and the size of the boat.
The diameter of the rose is also important, as it determines the size of the characters (numbers) that indicate the course. The apparent diameter of the rose should be proportional to the size of the boat and the reading distance. For a 6 to 9-meter boat, a diameter of 75 to 81 mm is recommended. For 8 to 12-meter units, a 100 mm compass is more appropriate. Over 12 meters, a steering column compass is preferable for yachts with a rose of at least 135 mm. The further the helmsman is from the compass, the larger the diameter of the rose should be to ensure optimum reading.
2 - Stability
Unlike electronic instruments, magnetic compasses operate without electrical energy, ensuring unfailing reliability. Comprising more than a dozen parts, some of them borrowed from the watchmaking industry, an approved compass undergoes several rigorous tests before being put on the market. Among them, vibration, stability and precision tests are crucial to guarantee its effectiveness.
The stability of the magnetic compass on a boat is essential for safe and accurate navigation. A stable magnetic compass provides reliable indications of direction, essential for navigation, especially on the high seas where visual cues are absent.
3 - Mounting option
There are several mounting options for a magnetic compass on a boat. The choice of mounting method depends on various factors, including the size and type of boat, but above all on the available space.
Pedestal or column mounting. The compass is mounted on a column or foot fixed to the boat's floor. This is often the case on sailboats fitted with wheel steering. Installed in this way, the compass is clearly visible to the helmsman.
Flush-mounted on a bulkhead. The compass is integrated into the dashboard, navigation console or cockpit bulkhead. It's well protected and easy to read.
Mounting on gimbal or yoke. The compass is mounted on a gimbal system which allows the compass to remain horizontal despite the boat's inclination. This keeps the compass horizontal, improving reading accuracy, but can make you seasick when trying to read it.
Bracket mounting
Portable or removable mounting. The compass is mounted so that it can be easily removed and moved. This is the case with Plastimo's Iris model, which can also be used as a bearing compass.
