Why Marinas, Shipyards, and “It Worked Last Time” Burn Boats
Introduction — shore power is the most abused electrical interface on yachts
For most yachts, shore power is treated as benign utility supply: plug in, lights stay on, generators stop. In reality, shore power is the single most variable and least controlled electrical source a yacht will ever connect to.
Voltage quality, phase sequence, earthing arrangements, connector ratings, and protection philosophy change dramatically between marinas, shipyards, and temporary supplies. The yacht, however, remains the same.
This mismatch is why shore power incidents dominate yacht electrical fire statistics.
Marinas vs shipyards — electrically not the same world
Marina supplies are typically designed for:
- multiple small consumers
- shared transformers
- long cable runs
- fluctuating loads
Voltage drop and imbalance are common. Protective devices are often sized for infrastructure protection, not yacht equipment sensitivity.
Shipyards, by contrast, provide:
- higher capacity connections
- shorter runs
- industrial protection philosophy
- temporary arrangements that change weekly
Both environments can be hazardous — for different reasons.
Phase sequence, neutral integrity, and false assumptions
Many yachts assume correct phase sequence and neutral stability. In marinas, this assumption is unsafe. Reverse phase rotation, floating neutrals, and shared earthing paths occur more often than crews expect.
Incorrect phase sequence can:
- reverse motor rotation
- confuse automation
- damage pumps and compressors
- defeat protection logic
Neutral faults can:
- over-voltage single-phase systems
- damage AV and hotel equipment
- create shock hazards onboard
None of this is visible at the socket.
🔧 Regulatory reality (what actually applies)
Yachts are not governed by SOLAS shore connection standards. Instead, they typically fall under:
- flag state yacht codes (LY3 / PYC / Large Yacht Code equivalents)
- IEC 60309 connector standards
- class requirements for changeover and protection
- manufacturer limits for voltage, frequency, and phase tolerance
Compliance requires verification, not assumption.
🔻 Real-World Case: Shore Power Fire — Mediterranean Marina (2019)
A large motor yacht suffered a major fire originating near the shore power intake. Investigation found:
- long-term undervoltage from marina supply
- elevated current draw
- overheating of connectors
- insulation breakdown
No breaker tripped.
The system operated continuously — until it ignited.
The supply was “within marina limits”.
The yacht paid the price.
Changeover — where mistakes compound
Switching between generator and shore power is a high-risk transition:
- loads are already energised
- protection settings change behaviour
- transient voltages occur
- human timing errors matter
Manual changeovers performed under pressure are a common precursor to failures. Automatic changeover systems reduce risk — but only if properly commissioned and maintained.
Professional yacht-engineer mindset
A competent yacht engineer asks:
- What is the quality of this supply, not just its rating?
- Have I verified phase sequence and voltage under load?
- Are connectors cool after one hour?
- Does the protection philosophy change between sources?
Shore power is not “free electricity”.
It is borrowed risk.
Knowledge to Carry Forward
Shore power failures on yachts rarely come from gross mistakes. They come from assumptions carried across environments. Every connection is a new electrical system — and must be treated as such.
If you didn’t verify it, you accepted the risk personally.
Tags
Yachts, Shore Power, Marina Electrical Safety, Shipyard Power, Electrical Fires, Yacht Power Changeover