The orders (b), (c) and (d) were those in practice in the Grand Fleet when circumstances permitted during my term in that command.

A typical route order from New York to Liverpool might be as follows: 

“After passing Sandy Hook, hug the coast until dark, then make a good offing before daylight and steer to pass through the following positions, viz: 

Lat. 38 deg.  N. Long. 68 deg.  W.
Lat. 41 deg.  N. Long. 48 deg.  W.
Lat. 46 deg.  N. Long. 28 deg.  W.
Lat. 51 deg. 30’ N. Long. 14 deg.  W.

“Thence make the coast near the Skelligs approximately at daylight, hug the Irish coast to the Tuskar, up the Irish coast (inside the banks if possible), and across the Irish Channel during dark hours.  Thence hug the coast to your port; zigzag by day and night after passing, Long. 20 deg.  W.”

Sometimes ships were directed to cross to the English coast from the south of Ireland, and to hug the English coast on their way north.

The traffic to the United Kingdom was so arranged in the early part of 1917 as to approach the coast in four different areas, which were known as Approach A, B, C, and D.

Approach A was used for traffic bound towards the western approach to the English Channel.

Approach B for traffic making for the south of Ireland.

Approach C for traffic making for the north of Ireland.

Approach D for traffic making for the east coast of England via the north of Scotland.

The approach areas in force during one particular period are shown on Chart A (in pocket at the end of the book).  They were changed occasionally when suspicion was aroused that their limits were known to the enemy, or as submarine attack in an area became intense.

[Transcriber’s note:  Chart A is a navigational map of the waters southwest of England, with approach routes marked.]

The approach areas were patrolled at the time, so far as numbers admitted, by patrol craft (trawlers, torpedo-boat destroyers, and sloops), and ships with specially valuable cargoes were given directions to proceed to a certain rendezvous on the outskirts of the area, there to be met by a destroyer or sloop, if one was available for the purpose.  The areas were necessarily of considerable length, by reason of the distance from the coast at which submarines operated, and of considerable width, owing to the necessity for a fairly wide dispersion of traffic throughout the area.  Consequently, with the comparatively small number of patrol craft available, the protection afforded was but slight, and losses were correspondingly heavy.  In the early spring of 1917, Captain H.W.  Grant, of the Operations Division at the Admiralty, whose work in the Division was of great value, proposed a change in method by which the traffic should be brought along certain definite “lines” in each approach area.  Typical lines are shown in Chart B.