(SENZAN MARU prewar)
IJN SENZAN MARU:
Tabular Record of Movement
© 2013-2018 Gilbert Casse, Bob Hackett and Peter Cundall
26 December 1928:
Tama. Laid down by Mitsui Bussan Zosenbu K.K shipyard for Dairen Kisen K. K. as a 2,775-ton cargo ship.
25 May 1929:
Launched and named SENZAN MARU. 
1 July 1929:
Completed and registered in Dairen, Manchuria (now Dalian, northern China). Her Gross Registered Tonnage (GRT) and Net Registered Tonnage (NRT) respectively are 2,775-tons and 1,588-tons. 
3 July 1935:
Two nautical miles E of Jizozaki, Azushima, Wakayama Prefecture. Under dense fog, SENZAN MARU collides with cargo ship (later IJA transport) MIDORI MARU.
11 April 1942:
At 1000 departs Takao alone with 3000 tons sugar. The ship sails at 9 knots.
16 April 1942:
At 0900 due to arrive at Dairen.
Departs Kirun, Formosa (now Keelung, Taiwan).
20 June 1942:
Strikes a reef and is stranded three nautical miles SW of Toseki Port Lighthouse, Tainan Province, Formosa.
21 June 1942:
Radioes for assistance. One tugboat and a small warship are dispatched and at 1730, succeed in refloating SENZAN MARU.
23 June 1942:
Arrives at Takao, Formosa (now Kaohsiung, Taiwan).
2 August 1942:
Requisitioned by the IJN.
6 August 1942:
Rated as an auxiliary transport under Navy’s secret instruction No. 9753.
8 August 1942:
Starts conversion to military duty at Maizuru Naval yard.
10 August 1942:
Registered in the IJN as an auxiliary transport attached to the Maizuru Naval District with Maizuru as home port under Navy’s instruction No. 1487. Attached that same day directly to the Combined Fleet as an auxiliary transport (Otsu) category under Navy instruction No. 574/27. 
12 August 1942:
Tactically assigned to maintenance and supply duties.
20 August 1942:
The conversion is completed. Undocked.
E August 1942:
Her GRT and NRT respectively are changed to 2,781-tons and 1,575-tons. 
21 August 1942:
23 August 1942:
Arrives at Tokuyama, Yamaguchi Prefecture.
26 August 1942:
Departs Tokuyama and arrives at Agenosho, Yamaguchi Prefecture later that day.
28 August 1942:
7 September 1942:
Arrives at Rabaul, New Britain.
24 September 1942:
5 October 1942:
Arrives at Tokuyama after passing through the Bungo Suido (Straits).
14 October 1942:
28 October 1942:
Arrives at Rabaul.
1 November 1942:
Tactically assigned to supply units in the Southeast Area.
15 November 1942:
2 December 1942:
Arrives at Maizuru after passing through the Bungo Suido.
23 December 1942:
26 December 1942:
Arrives at Tokuyama.
5 January 1943:
Departs Tokuyama for Rabaul with a cargo of gasoline.
16 January 1943:
At 0600, joined by subchaser CH-16 at 01-00S, 146-00E as escort to Rabaul. Escorted by unknown escort from Fukajima to 31 degrees north.
18 January 1943:
Off Kavieng, New Ireland. A USAAF Consolidated B-24 “Liberator” heavy bomber bombs and hits the transport. The gasoline is ignited by the explosion and SENZAN MARU sinks at 03-29S, 149-02E with the loss of seven
crewmen. CH-16 rescues survivors.
1 April 1943:
Removed from the Navy List under instruction No. 587.
 Not to be confused with IJA transport (1,151 GRT, ’18).
 NRT is a ship's cargo volume capacity expressed in "register tons", one of which equals to a volume of 100 cubic feet (2.83 m3). It is calculated by subtracting non-revenue-earning spaces i.e. spaces not available for carrying
cargo, for example engine rooms, fuel tanks and crew quarters, from the ship's gross register tonnage (GRT). Net register tonnage (NRT) is not a measure of the weight of the ship or its cargo, and should not be confused with terms such as deadweight tonnage or displacement.
 There were two categories of Zatsuyosen. (Ko) category with an IJN Captain as supervisor aboard and (Otsu) category without.
Thanks go to Gengoro S. Toda of Japan
Gilbert Casse, Bob Hackett and Peter Cundall
IJN Transports Page