In about an hour Roche and Flemming returned, having had a successful marketing, in spite of the language difficulty. Their French was unintelligible to the Harfleur shopkeepers, and the _patois_ of the latter equally so to the Sea Scouts, but by means of disjointed words and dumb show, Flemming and Roche had bought a goodly supply of necessaries. "Another eleven miles before we're through the canal, lads," announced Mr. Armitage as the _Olivette_ prepared to get under way. "You'll have to cut out a couple of cylinders, Roche, as we did in the Thames. Five miles an hour is the speed limit here." It was not a case of plain seamanship. The traffic on the canal was heavy, comprising small steamships and barges. Most of the latter were motor-propelled, but several were towed by steam-tugs, often three abreast in a string. More than once the _Olivette's_ stout rubbing-strake saved her from serious damage as the tail end of a line of barges took a sheer and swung nearly across the wide canal. Kilometre after kilometre was passed, but the long, perfectly straight canal seemed to have no ending, until early in the afternoon the _Olivette_ entered the Tancarville Lock, through which she had to pass to gain the River Seine. "We've a hot tide against us, sir," remarked Peter when the boat was breasting the swift current of the river. "Oughtn't we to bring up until the flood sets in?" "No," replied Mr. Armitage. "We must push on and try and reach Quillebeuf before then." Stratton looked puzzled. Knowing the Scoutmaster's usual keenness in "working the tides", it seemed strange that he should show anxiety to proceed against a strong current; while, by waiting a few hours, the _Olivette_ could easily make up for lost time by taking advantage of the flood tide. "We have the bore to take into consideration," was Mr. Armitage's enigmatical answer. "Let her all out, Flemming, and keep within easy distance of the reversing-lever; it may be wanted in a hurry." It took nearly an hour to cover the five and a half miles to Quillebeuf, but the Sea Scouts rather enjoyed the unusual scenery; Those not on duty were basking on deck until Mr. Armitage told them to go below. As the lads scrambled down the iron ladder into the well, they heard a faint distant rumble. "Thunder, by Jove!" exclaimed Warkworth. In a few minutes the roar increased. It certainly was not thunder. The Sea Scouts looked at each other inquiringly. They observed, also, that there was great activity on board the small boats at Quillebeuf. Men were busy casting off moorings and rowing the little craft into the centre of the stream. Suddenly round a bend in the river, down-stream, a huge wall of water was seen approaching at a furious rate and breaking heavily against both banks. To the lads this moving mass appeared to be quite twenty feet high, but in reality it was about one third that height.