the funnels of the troopship versions might be all-gray instead of gray with black tops. Unless this is just a Koko trademark or something?
A Koko thing pretty much by having, with few exceptions, all funnel tops black (basically, the AU explanation for "I personally like them that way"
Higashinada Maru class:
In order to increase passenger capacity on less prestigious routes Koko Kaiun Yuso Kaisha literally ordered an entire fleet of five liners between 1904 and 1912 to supplement the small Miyabi Maru. The ships became progressively larger as construction of the various units went on (much like the much more prestigious Arakawa Marus), but all relayed on the same basic design and maintained many features in common with each other.
The first ship of the quintet was Higashinada Maru, laid down in 1904 and delivered for her maiden voyage in 1906. She measured 143,9m in length overall, had a beam of 16,8m and a draft of 7,4m. Tonnage was 8.090 GRT. She fitted four boilers and triple expansion engine driving a single three-bladed propeller for a service speed of 15 knots. Passenger capacity was 812: 15 in first, 25 in second and 772 in third class, plus 213 crew. Higashinada Maru joined Miyabi Maru on the Koko-Hong Kong route, on which she served until her retirement in 1934.
Shizumacho Maru followed in 1906/1908, compared to Higashinada Maru she was longer and beamier, measuring 150,5m in the first case and 17m in the latter. Draft remained unchanged but the tonnage grew to 8.562GRT given the increased dimensions. The engines were not modified, so that the service speed decreased to 13 knots. Shizumacho Maru could carry a total of 860 passengers, 23 in fist class, 37 in second class and 800 in third class. Crew was 225. The ship opened dedicated passenger service between Koko and Korea in 1908, and kept doing so even after the Japanese annexation of the penninsula in 1910. In 1939 Shizumacho maru was finally withdrawn for service and scrapped.
The third ship, Hizu Maru, joined the KoKaYu fleet in 1910. She was slightly longer at 151,2m overall but retained the same 17m of her previous sister. Hull depth was increased however, without losing freeboard draft increased to 7,6m. Tonnage also rose to 8.831 GRT. Engines and service speed were the same as well, at 13 knots, and with the exception of the third class capacity increased to 816 both passenger and crew capacity was unchanged. Even taking into account some more small visual differencies Hizu maru was the ship that looked more similar to the one that preceded her. Like her near-identical sister Shizumacho maru, she served the Koko-Korea route, although by the time Hizu Maru docked there for the first time, the Japanese annexation had already taken place.
Hizu Maru was the oldest ship of the five at the start of WWII and possibly the most neglected of alll KoKayu ocean liners. She was requisitioned by Koko no kaigun and converted into a troopship, somthing that ironically saved her for a possible decommissioning given her age and state. During the works she recieved a much needed overhaul to her boilers -which were converted to all oil-firing. and engines. Repainted in an all-gray scheme she recieved a single old 120mm gun, two triple 25mm anti-air machine guns, searchlights RDF equipments, extra lifeboats and two landing crafts. The standard capacity was for 1.300 troops plus 154 crew.
She was sunk all hands in 1943 after being torpedoed by an USN submarine.
Mami Maru, the fourth ship, was laid down in 1910 an completed in 1912. She was lengthened to 155,3m and widened to 17,2m. Draft remained at 7,6m for a tonnage of 9.175 GRT. She sitted for boilers and triple expansion engines like her previous sisters but all were of improved -more powerful- types, something made obvious by the larger and taller funnel. Her service speed was 15 knots. Passenger capacity was 929: 58 in first class, 76 in second and 795 in third, plus a crew of 233. Mami Maru seved the Toumachi-Shanghai route between 1912 and 1937 before being moved to the Toumachi-Seoul when the second Sino-Japanese war broke out. In 1935 she also had her boilers converted from coal to oil-firing.
Like her other three sisters still in service, Mami Maru was converted into a troopship right after the start of the pacific war. She had a capacity of 1.300 trups and 154 crew like Hizu Maru.
Mami Maru held the much un-enviable record of being the first KoKaYu ocean liner being lost during WWII, bombed by allied carrier-based planes in November 1942 during the Guadalcanal campaign.
Kitamura Maru was the last of the five, entering service in 1914. She was over 14 meters longer than her predecessor at 169,7m overall. This because the decision to add a fifth main cargo hold that led to a much longer bow and the unique feature of being the only KoKaYu ocean liner with three masts. To compensate for the increased length, beam was taken to 17,5m and hull depth increased as well, for higher freeboard at the bow and a draft of 7,9m. tonnage was by far the highest of the quintet, at 10.606 GRT. As an oddity, she retained the single-screw machineries despite a twin-screw setup would have better benefitted her size. To offset this fact, she was given newer boilers, quadruple expansion engines and a four-bladed propeller (plus an enlarged rudder for maneuverability), yet this only mitigated the loss in service speed to 14 knots (although realistically she often did no more than 12 knots). Like Mami Maru she carried 58 first and 76 second class passengers, but third class accomodations were increased to 836, for a total of 970 passengers. Crew was 245. Her default service was between Koko and China, and she was a common sight in shanghai until 1937, after that she was moved to the Koko-Hong Kong route, not before being converted from coal to oil-firing.
Converted into a troopship like Hizu and Mami Maru, Kitamura Maru could usually carry 1.500 troops and a crew of 167. She was the longest lived on the three, staying afloat long enough to get a dazzle camouflage painted in early 1945.
Despite ending in the rebel's hand right from the start of Koko uprisings, she ultimately met her fate in late November 1945 when she hit an uncharted mine (possibly air dropped by the USN during the first days of the uprisings) off Tojima Island and capsized in a little more than an hour-and-half. Luckily with light casualties.