Hi Anizan,

There are not international standards that I am aware of for lightning protection specifically for naval ships, but I would also say that which relevant standard you use will depend on Navy concerned.


For the UK (and probably certain other navies within the commonwealth) there is a UK Defence Standard 02-516 Guide to Lightning Protection in HM Surface Ships. I am not as familiar with American Mil Standards but I would expect that there will be an equivalent for their ships.


For naval ships that are aligning themselves with Merchant Ship standards, there is a section in IEC 60092-401 Electrical installations in ships - Part 401: Installation and test of completed installation which covers lightning protection. This standard is currently under revision though the projected publication date of May 2021 is likely to slip, The requirements in this standard are matched by the requirements in the Classification Society Rules (e.g. Lloyd's Register, DnV-GL, ABS, etc.) of which LR publish Naval Ship Rules also, though unless you have a fairly old copy of the LR Rules they now just refer to IEC 60092-401..


Regarding the earth anodes, whether you need any or not depends on the ship. If it is a steel hull then a separate anode is a waste of time and money as the wetted steel surface provides a far better earth contact than anything you can add. If it is a non-metal hull (e.g. a fibreglass construction) then the standards (Def Stan/IEC/Class Rules) will address the location and surface area to be provided (from memory 2 m²), the conductor to be used between the mast and the copper plate, etc.


What is less well documented is the surge protection needed. The switchboards are not so vulnerable here, but sensitive equipment has been known to fail (e.g. radars and other Nav equipment) primarily because they are often electrically connected to items on the mast, while the switchboards are within a faraday cage. Where there is no protection provided, some captains have taken the precaution of ensuring at least one radar, etc. is switched off and isolated if there is a danger of a lightning strike as the loss of both radars will prevent the vessel from operating.


Hope this helps.


Alasdair

Thanks Alasdair Anderson