Without waiting to put on his oilskin, Craddock nipped up the ladder. His unwanted companion made no effort to stop him. In fact, he moved his legs aside. The rain was still descending in sheets. Through the mirk Craddock could distinguish the stern light of a tramp steamer that had just entered the harbour and was making for a berth beyond the swing-bridge. In vain the Sea Scout looked along the ill-lighted quay in the hope of seeing either Mr. Grant or a policeman or even a friendly fisherman. The idea that had flashed across his mind had taken root. He was firmly convinced that the fellow in the cabin was there for no good purpose. "I'll lock him in and go ashore for help," he decided, and measured the distance between the yacht's rail and the edge of the quay. By this time the tide had fallen considerably and was ebbing with great force. The coping of the masonry was a good five feet higher that the _Puffin's_ deck. "Don't want to find myself in the ditch," thought Peter. Through the slightly-opened skylight he peeped cautiously into the cabin. The stranger was in the act of transferring a revolver from his hip-pocket to the side-pocket of his jacket. The light of the cabin lamp glinted upon the dull steel of the sinister weapon. That was conclusive proof of the intentions of the fellow. Very gently Craddock felt for the padlock and key of the companion hatch, which when not in use hung from a hook just behind one of the double doors. With a feeling of elation his fingers closed over the required articles. The next instant the doors and the sliding-hatch were closed and the padlock slipped through the hasp that secured all three. So neatly was the operation completed that the man in the cabin was unaware of what had taken place. Possibly the thud of the raindrops upon the cabin-top had deadened the sound. "Don't stop out in the rain, boy!" he shouted. Chuckling over the success of his plan Peter went for'ard, intending to steady himself by the shrouds as he leapt ashore. Before he could do so there was a loud crack that sounded to him like the report of a pistol. Simultaneously the quay appeared to recede from the yacht. Already the distance between the two was too great for Craddock to leap. Then it suddenly dawned upon him. "The yacht's adrift!" gasped Peter. Absolutely certain that this was part of the stranger's scheme to smash up the Sea Scouts' yacht, Peter clambered into the bows. The part of the grass rope secured to the bits hung limply. The _Puffin_ was swinging out with her bows pointing towards the opposite quay and with the tide boring furiously against her port side. Kneeling, Peter fumbled for the chain. A distinct rasping sound told him that the anchor was playing false. Instead of holding, it was dragging. Then came another disconcerting sound--the splintering of wood from right aft. The warp on the port quarter had wrenched the cleat to which it was secured, from its fastenings.