5 and 6 Inch Compasses

Choosing a 5 or 6 inch compass answers a precise need for visibility and precision. On medium to large vessels, where the distance from the helmsman to the instrument can be significant, the card diameter guarantees quick readings without undue effort. These instruments often deliver superior stability thanks to well-compensated magnetic masses, reducing oscillations caused by wave motion.

When selecting a compass, you must carefully consider the installation position. A compass of this size requires a large mounting surface, typically in a console or on a pedestal, and must be kept away from ferrous masses or electrical wiring that can deflect the magnetic field. Checking the housing material and the UV resistance of the dome is a step we always recommend, given that the instrument will be exposed to sunlight for the entire working life of the boat.

Our role at Nautiba is to assist you in making the right choice. We don't just supply parts; we verify that the selected model is suited to your installation type, avoiding technical complications during fitting. We review the details together, such as the mounting surface inclination and the presence of compensators, elements that make all the difference during final calibration.

A correct installation always requires a compensation phase once the instrument is mounted on board. Remember that nearby AIS transmitters, GPS antennas, or electric motors can drastically affect accuracy. If you have doubts about compatibility between your boat type and the chosen compass model, our technical support is available to evaluate the specifications before your order is fulfilled.

Criteria for a correct choice

• Check the useful space for flush mounting: a 6 inch compass requires considerably greater depth and hole diameter than standard models.
• Check the support material compatibility: some compasses are designed specifically for flush mounting, others for bracket or pedestal mounting.
• Make sure the card readability suits your helm position: a tilted reading can cause parallax errors.
• Evaluate the presence of internal compensation systems, useful if the installation is close to metallic components or electrical systems.

What does magnetic compensation involve?

Compensation neutralizes deviations caused by on-board ferrous masses. It is a procedure carried out after installing the compass, using correcting magnets to bring the needle as close as possible to true magnetic north.

Does size affect accuracy?

The card diameter primarily affects the ease and speed of reading. A larger card is more stable and readable at a distance, making the instrument well suited to more spacious helm stations or extended passages.

Why is the dome material important?

The dome must be UV-resistant and scratch-resistant to maintain transparency over time. A poor-quality material can yellow or cloud over, making the compass impossible to read in direct sunlight.

Can I mount the compass near the GPS display?

It is inadvisable. Electronic devices generate electromagnetic interference that can deflect the compass needle. A minimum safe distance must be maintained, usually indicated in the technical manual for each specific compass.