The remaining pontoons were therefore constructed, and preparations commenced in the greatest secrecy for the whole operation.
The next matter for trial was the arrangement devised by Sir R.Bacon for making it possible for tanks to mount the sea wall.

These trials were carried out with great secrecy against a model of the sea wall built at the Headquarters of the Tank Corps in France, and were quite successful.

It was necessary to see actual photographs of the tanks mounting the coping at the top of the sea wall to be convinced of the practicability of the scheme.

A matter of great importance was the necessity for obtaining accurate information of the slope of the beach at the projected landing places in order that the practicability of grounding the pontoon could be ascertained.

This information Sir R.
Bacon, with his characteristic patience and ingenuity, obtained by means of aerial photographs taken at various states of tide.
Finally, to gain exact knowledge of the rise and fall of the tide, Admiral Bacon employed a submarine which submerged in the vicinity of Nieuport and registered the height of water above her hull for a period of twenty-four hours under conditions of spring and neap tides.
The preparations for the landing involved much collaboration with the military authorities, and Sir Reginald Bacon was frequently at G.H.Q.
for the purpose.