Earthing of Equipment in Off Shore / Aeroplane

Oil platforms and most land refineries use a high resistance grounded electrical supply to minimize the risks of explosion when a short circuit to ground occurs. Believe me it happens regularly in these plants. They do not like large sparks to occurs near flammable liquids or gas. (Do I need to explain why?) To obtain this, the transformer neutral is grounded through a resistor to limit the short circuit current to about 5A. When this happens the line to line voltage is not affected but the line to ground voltage changes drastically. This can affect and destroys equipments designed for a solid grounded supply.

As far as the rest of the equipment grounding is concerned, the structures and cabinets are bounded to the local ground the same as in any other industry.

The same should apply to a boat as what is important is not to be connected to earth but to be at the same potential as the surface you are standing on.

It is a mis-conception that the earth is a black hole for electricity. Electricity does not get absorbed in the ground, it simply returns to the source that is also grounded. Since the earth is not such a good conductor, we always (except utilities but this is an objectionable case) add a grounding conductor with any supply to provide an easy return path. The equipment bounding to earth is simply to prevent having a potential difference between the conductive surface and the floor.