A captain berths at a Mediterranean marina, there is a shore power pedestal on the pontoon, and the generator still runs all night. It is not carelessness. Very often the vessel simply cannot use that grid.
The problem: two grids that do not speak the same language
Frequency. The European grid runs at 50 Hz. Many large yachts are built with 60 Hz systems, the standard in the American market and for much marine equipment. Air conditioning, pumps, compressors and onboard transformers are designed for that frequency.
Voltage. Ports supply different voltages and configurations from country to country, and the vessel’s switchboard expects one in particular.
Capacity. Pontoon outlets usually have limited current. A 30 to 45 m yacht running air conditioning in summer can need more than a single outlet provides.
Why plugging in is not enough
Running 60 Hz equipment on 50 Hz is not harmless. Motors turn more slowly, and transformers and motors carry more magnetic flux than designed for, run hotter and age faster. Over time, that gets expensive.
On top of that, connecting the vessel directly to shore without isolation exposes the hull to stray currents that accelerate electrolytic corrosion.
The usual options
| Option | Fixes voltage | Fixes frequency | Note |
|---|---|---|---|
| Onboard isolation transformer | Yes | No | Protects against corrosion, but the vessel is still tied to the port’s frequency |
| Shore-side frequency converter | Yes | Yes | Depends on that marina having one, and they are costly and scarce |
| Onboard converter | Yes | Yes | The vessel carries its own solution to every port |
What a well-designed onboard converter brings
An onboard converter solves the problem once, for every port. But they are not all the same. These are the questions worth asking:
- Is it universal? It should accept 50 and 60 Hz and a range of input voltages.
- Does it have galvanic isolation? Essential to protect the hull.
- Does it transfer without interruption? Switching from generator to shore power without anything on board going off.
- What does it lose? Efficiency matters: it is energy you pay for all year.
- Does it affect the port grid? A converter with high harmonics can cause problems for the marina.
- Will it fit? In a refit, engine-room access is usually the limiting factor.
How SHP-X answers them
SHP-X is universal (50/60 Hz), with galvanic isolation and seamless transfer. When the port grid matches the vessel’s, it goes into bypass and the electronics step aside. Its three-stage architecture, versus the standard five, cuts conversion losses by 40%, with THD below 3% and power factor above 0.99. And its modular version fits through the hatch.
Validated aboard a 32.9 m Sanlorenzo SL108 (The Petrus case). On sale from March 2027, up to 250 kW.
Is your vessel still running its generator in port? Let’s talk.