Having studied marine statistics for a number of years, especially those concerning casualties at sea and in particular collisions between ships, the opening paragraph of the Traffic Separation Working Group's report (this Journal, 19, 4) is, to say the least, lacking confirmatory evidence on two counts.

I refer to the general statements which allege that:

(i) ‘The main risk at sea today arises not as it used to from stranding and shipwreck, but from collision’.

(ii) ‘In the open sea, where nearly 30 per cent of all collisions occur…’

As both include the words ‘at sea’ or ‘open sea’ it is not unreasonable to suppose that they imply freedom to manœuvre under own power unhampered by depth of water or similar navigational restriction.

This being so, and not an irrational definition of the area of concern to the Working Party, what are the facts and how exactly do casualties at sea compare with those in other areas of marine interest throughout the world.

To find the right answer to the global problem is not easy and there are no short cuts, such as for example making a sample analysis in a limited area where traffic density is high, in order to arrive at fairly large numbers which are then used to deduce the statistical probability applicable to all areas.