Before his death, my grandfather told my dad that he served in one of three Chinese cruisers in WW2 called the "Hai" something...
I regret not paying much attention to the second word... My dad either... he said it sounded like "Chi" or "Chen"...
Here is the most likely candidate : http://ww2db.com/ship_spec.php?ship_id=815
A ship that was in the Chinese navy around WW2, had two sisterships.
Where would you go or who would you ask for the ship manifests?
This isn't as difficult as you may have believed. You see, during the Second Sino-Japanese War in WW2, the Chinese Navy was pretty badly equipped and basically only had six cruisers in total: the Yi Xian, Hai Rong, Hai Qi, Hai Shen, Ning Hai, and Ping Hai.
Of those six, I suspect two of the Hai Rong-class cruisers, built by AG Vulcan Stettin, may be what you're looking for. You see, despite being named Hai Qi and Hai Shen in Mandarin Chinese, their names have also been rendered as Hai Chi and Hai Chen. So you likely found the right one already. Their history, and eventual fates, are tied, making this much easier to trace.
Both these cruisers were commissioned alongside the lead ship of their class, the Hai Rong, by Qing China as part of their efforts to modernize the imperial navy following the defeats at sea during the First Sino-Japanese War. During the rebellion that led to the fall of Qing China, these ships, along with most of the imperial navy, switched sides to join the rebels. They later became part of the Republic of China Navy (ROCN), but were technologically obsolete by the time of the Second Sino-Japanese War during WW2. After the fall of Shanghai and Nanjing, the Hai Qi/Hai Chi and Hai Shen/Hai Chen were both scuttled in the Yangtze River as delaying obstacles against the Japanese Navy who needed to use the Yangtze to provide supplies to the Japanese Army.
The ship manifests would probably be in the hands of Taiwanese authorities by now. I would first try the Republic of China Armed Forces Museum in Taipei, Taiwan. Even if they don't have it, they could probably point you in the right direction from there.
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