corrugated
iron and weather-board. The doors flanking the passages traversed
display cryptic lettering, such as I.O. (Intelligence Office), S.R.
(Signal Room), S.N.O. (Senior Naval Officer), "Commander" (usually the
second in command of the base), P.M.S.O. (Port Minesweeping Officer),
C.B.O. (Confidential Book Office), M.L.Com. (Motor Launch Commander),
O.O.W. (Officer of the Watch), "Officers only" (the wardroom and
gunroom combined), and, finally, the O.O.D., or the abode of that
much-worried individual, the Officer of the Day, whose duties happily
terminate when his twenty-four hours of administrative responsibility
are over, only, however, to return in strict rotation.

[Illustration: FIG. 17.--The central pier of a typical anti-submarine
naval base. 1. Wardroom. 2. Sec. to senior naval officer. 3. Admiral's
cabin (S.N.O.). 4. Flag commander (or lieutenant). 5. Base intelligence
office. 6. Base commander. 7. Chaplain and gift store. 8. Drafting
officer. 9. Store officer. 10. Chart-issuing office. 11. Cabin of the
officer of the day. 12. Telephone exchange. 13. Warrant officers. 14.
Pay office. 15. Fleet paymaster. 16. Paymasters and asst.-paymasters.
17. Writers and W.R.N.S. 18. Engineer-commander's office. 19. Men's
quarters (for base duties and reserve). 20. Men's recreation room. 21.
Petty officers. 22. Men's mess-room and adjoining galley. 23. Sick-bay.
24. Fleet surgeon. 25. Baths. 26. Baths. 27. Stores. 28. Boom defence
office. 29. King's harbour master. 30. Hull defects office. 31. Police
and cells. 32. Coaling office. 33. Wireless cabin. 34. Guard room. 35.
Railway platform. 36. Sentry box. 37. Cranes. 38. Berths for armed
yachts in harbour. 39. Motor launches in harbour. 40. Drifters. 41.
Patrol trawlers. 42. Minesweepers. 43. Whalers. 44. Coastal motor boats.
Larger ships, such as sloops, destroyers, "P" boats, coaling and
ammunition hulks, lying out in basin.]

Again comes an apologetic examination of credentials, possibly followed
by a few minutes with the admiral commanding, and then the grand tour
commences. First come the ships lying alongside the stone pier, with
their short funnels belching black and very sooty smoke. These are the
"stand-off" units, whose crews are enjoying a brief few hours ashore
after days or weeks out on the dangerous seas beyond. Big drums of oil
are being lowered by ropes on to their decks. The sound of hammering
comes from more than one engine-room, where machinery is bein