Dr Watson discovers an automatic pistol --- i.e., one with a slide-in ammo-clip instead of a rotating cylinder --- in a lady passenger's handbag. He consistently refers to the handgun as a revolver. An ex-Army officer like Watson, no matter how daft, would never make such an "obvious" mistake.
In the final shot of the telegraph in the ship's engine-room being used, the pointer moves AFTER the hand operates the handle instead of before it, and the handle jiggles BEFORE the engineer's hand reaches for it; obviously "recycled" footage of a previous shot of the telegraph's operation, played in reverse.
Gubec, the deaf mute, shoves Holmes out of camera range and in five seconds has him not only bound securely with rope but gagged with a knotted handkerchief as well.
When the villain Gubec (Wee Willie Davis) knocks out Sherlock Holmes and throws him on the cot in the stateroom, Holmes re-positions himself using his legs even though he's supposed to be unconscious.