To do this, water craft and aircraft of various kinds are needed; and they must be not only sufficiently numerous over each area to scout the waters thoroughly, but they must be adapted to their purpose, manned by adequate and skilful crews, and organized so as to act effectively together.
The work of this patrol system is not to be restricted, however, to getting and transmitting information.

Certain of the craft must be armed sufficiently to drive off hostile craft, trying to drag or countermine the defensive mine-fields; some must be able to add to the defensive mine-fields by planting mines, and some must be able to pilot friendly ships through the defensive mine-fields; others still must be able to countermine, drag, and sweep for any offensive mines that the enemy may plant.
Vessels for this patrol work do not have to be very large; in fact, for much of the work in the mine-fields, it were better if they were small, by reason of the ability of small vessels to turn in restricted spaces.
It would seem that for the patrol service, the vessels of the Revenue Marine and Lighthouse Service (coast guard) are ideally adapted; but, of course, there are only a few in total.

These would have to be supplemented by small craft of many kinds, such as tugs, fast motor-boats, fishing-boats, and trawlers.

To find men competent to man such vessels and do the kind of work required would not be so difficult as to get men competent to man the more distinctive fighting ships.

Good merchant sailors, fishermen, and tugboat men would fit into the work with considerable ease, and in quite a short time.