Electronics are the fastest-ageing part of a boat. With good care the hull and engine last for decades; navigation equipment has an economic life of ten to twelve years. On a listing that says "fully equipped", the age of that equipment is usually the invisible line in the budget.
This page sets out how navigation electronics are assessed in a survey and what to expect at each age.
Scope note: A survey documents whether equipment works, how well it was installed and how old it is. Software updates, calibration and fault repair are separate work, coordinated with an authorised dealer.
1. Life Thresholds
| Equipment | Economic life | What happens with age |
|---|---|---|
| Chartplotter | 8-12 years | Chart updates stop, the screen fades, touch sensitivity drops. |
| Radar (dome / open array) | 10-15 years | The magnetron weakens and range falls. Broadband radar lasts longer. |
| AIS receiver / transceiver | 10-12 years | Class A/B standards move on; older units may not meet current protocols. |
| Autopilot | 10-15 years | Hydraulic pump and drive tire; course computer and display fall out of step. |
| VHF (DSC) | 10-15 years | The MMSI registration must be verified; older DSC sets may lack a GPS feed. |
| Depth / speed / wind sensors | 8-12 years | Sensors foul, calibration drifts, readings wander. |
| Satellite communications | 6-10 years | Providers change networks; a unit can fall out of support. |
| Cameras and thermal imaging | 8-12 years | Sensors degrade, sealing weakens. |
2. What Happens in the Survey
- Power-up and display: each unit is run; does it display, does the touchscreen respond.
- Data flow: whether devices see each other on the NMEA 0183 / NMEA 2000 network; missing or dropped sensors.
- Aerials and connections: connector oxidation, water ingress, sealing at deck penetrations.
- Software version: current, and still supported by the manufacturer.
- Installation quality: how later additions were wired; unfused runs and domestic connectors are the most common finding.
- Power draw: total electronic load against battery capacity.
- Redundancy: what is left if the main system fails, compass, handheld VHF, backup GPS.
3. The NMEA Network: Where Trouble Starts
| Looked at | Why it matters |
|---|---|
| Backbone and termination | A NMEA 2000 network needs a terminating resistor at each end; without them, data loss looks like an intermittent fault. |
| Network power | Fed from a single point; dual feeds create conflict. |
| Mixed generations | Different makes and years on one network, incompatibility usually starts here. |
| 0183 / 2000 converters | Where old and new run together, an extra point of failure. |
| GPS source | With more than one GPS, which takes priority; conflicting position data is dangerous. |
4. Autopilot: Assessed Separately
- Course computer, display and drive unit working together
- Condition and sound of the hydraulic pump or linear drive
- Rudder feedback sensor calibration
- Emergency stop and manual takeover response
- On sea trial: actual course keeping and correction behaviour
5. Radar and AIS: Presence Is Not Enough
- Radar: does it turn, does it paint targets, do the range scales work. On a magnetron set the decline is gradual and the owner rarely notices.
- AIS: receiver only, or transceiver. Where there is a transmitter, the MMSI registration is verified against the vessel, on transferred boats the previous owner's MMSI often remains.
- Aerial placement: VHF and AIS aerials not shadowing each other; where a splitter is used, its condition.
Forgotten after transfer: MMSI and EPIRB registrations do not pass with the boat; they must be re-registered to the new owner. The survey asks about the state of these records.
6. Realistic Budget Figures
| Scope | Approximate budget |
|---|---|
| Single chartplotter replacement | €1,500-4,000 |
| Plotter + depth + speed/wind | €4,000-9,000 |
| Autopilot (drive included) | €3,500-9,000 |
| Adding radar | €2,500-7,000 |
| Full electronics refit (12-15 m) | €12,000-30,000 |
Figures vary with brand, installation labour and the state of existing cabling. Where the existing runs can be reused, cost drops markedly.
7. What to Check When Buying
- Ask the age. "Fully equipped" carries no age information.
- Look for one generation. Mixed ages and brands are the main source of network trouble.
- Check the chart subscription. A plotter with no updates is not much cheaper than a new one.
- Inspect the installation. Expensive equipment badly wired gives more trouble than mid-range equipment wired well.
- Ask about redundancy. A boat built around a single screen goes blind when that screen dies.
See electrical survey for the power side and the survey calculator for scope and fee.
Frequently Asked Questions
Economic life runs 8 to 15 years depending on the unit. Plotters and sensors are renewed earlier, radar and autopilot later. A unit that still powers up but has lost software support has effectively reached the end of its life.
Usually the NMEA network: a missing terminating resistor, dual power feed, or mixed-generation incompatibility. Units working individually does not mean the system works.
On magnetron sets the output falls gradually; range shortens and weak targets disappear. Because it is slow, owners rarely notice.
The MMSI belongs to a registration, not to the hull, and does not pass on sale. On transferred boats the previous owner's MMSI often remains; it must be re-registered to the new owner.
On a sea trial, yes: course keeping, correction behaviour and manual takeover are observed. Ashore only power-up and calibration state are checked.
On a 12-15 metre boat, roughly €12,000-30,000. Where existing cabling can be reused, the cost drops markedly.
No. The survey records condition and software version; updates, calibration and repair are separate work coordinated with an authorised dealer.
Scope: The survey is non-destructive and nothing is dismantled; details on the survey types page.
Continue with this topic
- Autopilot: Drive, sensors and testing.
Related Pages
Electrical SurveyBatteries, charging, stray currentSea Trial ChecklistWhat gets checked on trialEngine SurveyHours, cold start, shaft lineRepair Guide100 defects and realistic costCommon Boat DefectsWhat comes up most oftenSurvey QuoteFee by length and scope
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