SHIPS' DIARIES & SURGEONS' REPORTS etc.

I need to locate Diaries, Surgeons' Reports, Logs etc which may give me information on births and deaths on the following voyages: 1. City of Washington, Liverpool to New York departing 25 May 1859 - I'm interested in the THEXTON family. 2. Rimutaka, Auckland New Zealand to Plymouth Great Britain, departing 6 May 1886. I'm interested in the STOREY. GANE and LITCHFIELD families. Do these documents survive - and if so, where are they held? Thanks for your help. HELBEL