There was nothing to be done for Masters; no occasion for lingering there helplessly.  The yacht was sinking under their feet, going down slowly, but surely, and the end could not be far off.  The very movement of the vessel sickened him, brought to him a sensation of fear.  Moreover he knew the truth now, and saw clearly his duty.  The watchman had not told much, but it was sufficient to verify all his former suspicions.  These fellows he fought were desperate criminals, playing for high stakes, conspiring to even commit murder to achieve their object—­which could be nothing less than gaining possession of the Coolidge fortune.  To that end they had coolly planned the sinking of the Seminole in mid-lake, with the helpless girl locked securely in her cabin.  It was a cowardly, diabolical crime, and yet, no doubt, they had figured it as the safest method of completely disposing of her.  And, but for the accident of his presence on board, and his having been awakened by that incautious voice, the foul plot would probably have proven successful.  They had already got safely away, leaving her behind a prisoner, her only possible rescuer this watchman wounded unto death.  The yacht was sinking in the dark, going steadily down in those night shrouded waters.  Who would ever know?  The main body of the crew, perhaps, never even dreamed of her presence aboard.  There was no evidence, nothing to convict the men really guilty.  Here was the scheme of a master-mind in crime.  West weaved his way across the rolling deck of the cabin to the stateroom door Masters had pointed out as the one sheltering the girl.  There was no sound from within, nor would the knob yield to his grasp.  It was locked, the key gone.  There was no time to wait and hunt for that missing piece of metal doubtless safely hidden in Hogan’s pocket, or else thrown overboard; he must break a way in; but first he must explain to her, so as to spare her the sudden fright of such an assault.  He rapped sharply on the panel, pausing an instant for a response.  None came, and he knocked again more roughly.

“Miss Coolidge:  you are there, are you not?”

“Yes; who is that?” almost a cry of delight in the voice.  “You—­you have a voice I know.”

“I am Matthew West; but do not ask questions now.  The yacht is going down, and I must break this door in to release you.  Stand back while I smash the boards.  You hear and understand?”

“Yes—­yes:  I am safely away; have no fear.”

The light revealed the weapon he required just beyond where Masters lay—­a heavy hatchet, still stained with blood, probably the very instrument with which the watchman had been brutally struck down.  That made no difference now, and West snatched it up, and began to splinter the wood with well directed blows.  He worked madly, feverishly, unable to judge there in the cabin whether he had a minute, or an hour, in which to effect their rescue.  All he knew was that every second was worth saving, and with this impulse driving him, swung the sharp blade with all his strength and skill, gouging out great splinters of wood, and finally forcing the lock to yield.  He sprang eagerly through the opening, the hatchet still in his grasp, and faced her.