The short answer
Before replacing a pilot's course computer, inventory everything from helm to display: actuator type and effort, voltage and current, rudder sensor, attitude, heading, wind, speed, networks, controls, protections and manual-recovery procedures. For every element you keep, demand an interface proof — reference, signal, range, protocol and failure behaviour. Madintec's boxes can ease a conversion, but brand compatibility or the presence of NMEA 2000 is not enough. The audit's output must be a "kept / replaced / to test" bill of materials, a target diagram and a test plan — not a list of adapters chosen after the fact.
Photograph and reference what exists
Start without unplugging anything. Photograph every box, connector, protection and terminal with its label readable. Record references, version numbers, voltages and available diagrams. Draw the cables as actually routed, even if the original plan says otherwise. Identify the course computer, power unit, actuator, rudder sensor, compass or motion sensor, wind vane, displays, remotes and interfaces. Note what works, intermittent faults and parts already replaced. This baseline lets you compare the target Madintec system without confusing a similarly named product with the device actually installed.
Audit the steering mechanics
The pilot must move the rudder or steering system through its full range with the required effort and speed. Record steering type, quadrant, tiller arm, linkages, end stops, stroke and maximum angle. Look for play, hard spots, leaks and flexing. For a hydraulic ram, identify volume, pressure, pump, valves and bypass. For an electromechanical actuator, record stroke, force, speed, voltage, current and duty cycle. Our hydraulic vs electromechanical guide helps structure that comparison.
Do not keep an actuator merely because it works at the dock. You must demonstrate it is compatible with the target MAD Controller and suited to the boat's loads at sea.
Measure the electrical architecture
Record nominal voltage, protection ratings, cable gauge and round-trip length, grounding point and connection condition. Measure voltage at the computer and at the power unit at rest, then under load. A refit can increase computing, network or control needs without changing actuator current; conversely, keeping an old pump can impose a draw the new unit cannot drive. Treat electronics supply and steering power separately. Provide an accessible cut-off and compliant protection on each circuit: the pilot must be isolatable without killing unrelated essential equipment.
Qualify every sensor
For attitude and heading, note the actual source, protocol, rate and any other emitters of the same data type. For wind, identify NMEA 0183, NMEA 2000 or a proprietary link, plus the rate and the sentences or messages available. For rudder angle, record voltage, range, direction and geometry. The MADBrain brochure describes CAN, Ethernet and serial interfaces plus dedicated acquisition modules — several possible paths, each of which must be validated. Data visible on a display is not proof it is available at the rate and format the computer requires.
Classify every sensor: "documented compatible", "test required" or "replace". Avoid the "should work" category.
Map the networks and their boundaries
Draw NMEA 2000, NMEA 0183, Ethernet, proprietary CAN and analogue links separately. Mark terminations, power feeds, gateways and data direction. An interface crosses a defined boundary; it does not merge every network. On NMEA 2000, check the backbone, drops, both terminators and the current budget. On NMEA 0183, check talker, listener, electrical level, baud rate and sentences. On Ethernet, check addressing, switches and application compatibility. Decide which source is authoritative for each data type: two simultaneous headings or winds can produce unpredictable behaviour if the selection changes.
Define controls and manual recovery
List the stations: helm, cockpit, interior, wired and radio remotes. For each, note the required actions: engage, disengage, adjust, change mode, tack or gybe where provided. Verify the manual-recovery procedure and actuator declutching: it must be understandable by the crew and workable without hunting for an app. Add the behaviour on loss of remote, network or power. A more elegant interface is not an improvement if stopping the pilot becomes less accessible.
Build the target bill of materials
For every existing element, write the decision and its proof. Example: actuator kept after current/stroke validation; rudder sensor replaced; wind vane kept via MAD Interface Mast after NMEA 0183 checks; remote replaced; NMEA 2000 network brought back to spec. Add the often-forgotten items: cables, fuses, breakers, fittings, converters, brackets, waterproof boxes, software licence, commissioning and sea trials. The BOM must carry exact references and document versions. If a compatibility remains uncertain, plan a bench test or a measurement before ordering — do not turn uncertainty into a pile of adapters.
Commission in stages
At the dock, validate power feeds, networks, sensors, rudder angle, actuator direction and cut-off. Check the end stops without forcing. Test controls and manual recovery. In calm water, start at low speed under supervision. Validate heading mode, corrections and consumption. Then move to wind or performance modes with data already verified. Increase conditions progressively. Simulate controlled losses: sensor, network, remote and voltage sag. Record reactions and messages. Commissioning is complete when normal and degraded behaviour is documented for the crew.
The autopilot hub helps match component families to the target diagram.
Official sources
Madintec — MADBrain autopilot and integration; official French MADBrain brochure, archived in the Skysat documentation base on May 6th, 2026. NMEA — official information on the standards.
