Bound log book titled “Information concerning P.V. Gear in 13th Flotilla”. There is an index of the 26 ships listed in the log: Medway, Moresby, Narborough, Nepean, Nictator, Nereus, Norseman, Obdurate, Octavia, Oracle, Onslow, Oriana, Orpheus, Oriole, Orsis, Oberon, Pelican, Paladin, Penn, Petard, Pigeon, Paisley, Pylades (all Admiralty M-Class); Nerissa and Rival (Yarrow M-Class) and Patrician (Thornycroft M-Class). Following the index, beginning on page 100 are entries about each ship. Paravanes (P.V.) are devices towed behind a vessel at a regulated depth, so that the cable to which it is attached can cut the moorings of submerged mines. It was a new weapon in World War I. In addition to information about the paravanes, the log also contains maintenance and circuit test notes. Two of the destroyers, Oracle (p. 149) and Pasley (p. 169) had collisions with submarines.