An unusual version of the Seafarer, perhaps a prototype.  Notice that (a) the 30-minute register is "rotated" 90 degrees, so that the Zero / 30-minute mark is at "9 o'clock", rather than at "12 o'clock" and (b) the tide dial is mounted behind the main dial, with a semi-circle cut-out to show the tide dial, so that only half the tide dial is visable.  [In this section, this chronograph is identified as "AFSF1" (Abercrombie & Fitch Seafarer Number 1)]