War, whether it be on the sea, under the sea, on the land or in the air, is a science in which the human element is of at least equal importance with that of the purely mechanical. It is a science of both "blood and iron."

The armed motor launches described in earlier pages, after being built in Canada to the number of over 500, and engined by the United States, were transported across the Atlantic on the decks of big ocean-going steamships—more than one of which was torpedoed on the voyage. On their arrival in Portsmouth dockyard the guns and depth charges were placed aboard and the vessels thoroughly equipped and fitted out for active service.

Officers and men were drafted from the training establishments of the new navy at Southampton, Portsmouth, Chatham, Greenwich and elsewhere. Each little vessel was given a number, and within a few weeks of their arrival from the building yards on the St Lawrence they sailed in flotillas out past the fortifications of Spithead, en route for their respective war bases.

Great secrecy had surrounded the construction of these small but powerful craft, and but few naval men, except those directly engaged in the anti-submarine service, had either seen or heard much of them until they commenced arriving at the different rendezvous.

Among the early flotillas to leave Portsmouth dockyard was one of four ships destined for a base on the east coast of Scotland, and as these speedy little craft raced away north the expectations of both officers and men ran high.

It was in the early summer of 1916, and although the air was crisp, the sea sparkled in the bright sunlight and the sky was a cloudless blue. Only a heavy-beam sea off Flamborough Head had marred the maiden voyage, and they were now on the last hundred miles, with the low-lying Farne Islands fading into the mist astern. By nightfall, if the wind remained light, they would make the Scottish port which was to form their base of operations.

Hitherto these four brand-new little warships, all white wood, grey paint and polished metal, had been plodding over the 600 miles of sea from Portsmouth at what was termed "cruising speed"—a mere 10 knots. The engines had not been opened out to "full ahead" because these delicate pieces of mechanism needed time to settle down to their work before it was safe to drive them to the utmost limit of speed and power, but now that pistons and bearings had been given time to "run in" it was considered safe for the flotilla to increase speed in order to make harbour by nightfall.

A hoist of new, bright-coloured flags fluttered from the squat mast of the leading ship. The steady throbbing of the engines grew suddenly to a low staccato roar. The white waves astern rose up almost level with the counters and clouds of fine spray blew across the decks. This rapid movement through the sun-lit water, with the breeze of passage and the tang of the salt sea in every breath, was exhilarating, and the spirits of those aboard rose with the speed.

Running at nearly half-a-mile a minute, the flotilla forged northwards through clouds of fine, stinging spray, until at a late hour, when the sun was dipping below the horizon and the sea was a sheet of golden light, a smoky line appeared far away to the westward. It was that section of the Scottish coast which in future it would be the duty of these boats to patrol, and as the distance lessened those on board gazed in silence at the gigantic cliffs and black rocks, now tinged with the rays of the dying sun and encircled by the endless ripples which alone broke the peaceful surface of the sea, but one and all were picturing this forbidding coast on the stormy winter nights to come.

Slowly the light faded from the western sky. The cliffs rose up black and sombre, and when the little flotilla turned westwards up the broad waterway leading to the base darkness had closed over land and sea. For some time they picked their way up this sheltered loch. No lights were visible, but more than once a destroyer appeared out of the blackness to make sure of their identity, and each time they were inspected very closely before the guard-ships were satisfied. An armed trawler guided them past dangerous obstructions and then faded into the night. Mile after mile of water was then traversed on courses laid down in confidential orders.