Miles and nautical miles


A chara, – In relation to the Sea Fisheries Bill allowing Northern Irish vessels to fish in restricted Irish waters, several articles have referred to a “six-mile” exclusion zone to which Northern Ireland vessels will be given access, always converted as 9.6 km.

The English statute mile, now obsolete in this country, is indeed just over 1,600 metres. However, the legislation confirms that the “mile” in question is the longer nautical mile, which is 1,852 metres in length. This translates to 11.1 km – a full kilometre and a half extra for our Northern neighbours to enjoy.

While we can assume that the Naval Service will use the correct “mile” when deciding whether a vessel is fishing legally or not, the understandable confusion your staff experienced grappling with conversions illustrates why our laws should be in standard metric units only.

Leave the nautical-mile conversions to those who use them every day. For the rest of us, while a mile may not always be a mile, a kilometre will always be a kilometre. – Is mise,



Sir, – In your news report on legislation to allow Northern Ireland fishing vessels to operate within our “six-mile” limit, this is explained as “six miles (9.65km) out to sea”. While six statute miles are indeed equivalent to 9.65km, I understand that our fishing limits are defined in terms of “nautical miles”. Thus the “six miles” mentioned are, in fact, roughly equal to 11.1km.

It may interest some people to know that six “Irish miles”, in what is now legally known as the “former Irish Plantation measure”, would be even longer, ie 12.29km or 7.64 statute miles, raising a serious question about the exact meaning of the old Co Down song ’Tis six miles from Bangor to Donaghadee! – Is mise,


Dumhach Thrá,

Baile Átha Cliath 4.