midnight
`` That is all right , '' commented Don Hermoso , when the statement was passed on to him ; `` the gentlemen of the customs will not be troubled with sleeplessness to-night ! '' Nor were they ; for four bells in the first watch had scarcely struck when , with many yawns , they retired below and -- those who were supposed to be on watch as well as those who were off -- in ten minutes were sleeping like logs . `` Now is our time , Phil , before the moon rises , '' exclaimed Jack , as soon as the report of the custom-house officers ' retirement had been brought aft by the chief steward . `` It is important to get the submarine into the water unobserved ; but , that done , we can wait until midnight , or even later , before commencing operations . By that time everybody will have turned in ; and moreover we shall have the light of the moon to help us . '' Accordingly , the canvas cover was removed from the particular boat in which the small submarine was hidden , and the mischievous little toy was carefully hoisted out , lowered into the water , submerged until only the top of her diminutive conning tower showed above water , and then effectually concealed by being moored to the boat boom , between the gig and the steam pinnace . Then advantage was taken of the darkness to pass down into her everything that had been prepared for the success of the forthcoming enterprise ; after which everybody turned in , except Carlos , who undertook to keep a watch on deck until everything should seem sufficiently quiet in the harbour to admit of the adventurers beginning their work without incurring undue risk of detection .