This may have been available many moons ago but there is an up to date copy. Survivalblog.com said "As ships at sea represent a majority of the attributes of a Bugout, Offgrid Retreat, long-term self-sufficient vessel we all aspire to mimic day to day, I thought it prudent to pass along one of the required shipboard medical books all large ships carry."
They then linked to Amazon for a £53 book !!
Here's a download freely and legally available - originally published from the UK Maritime and Coastguard Agency.
Ship Captains Medical Manual
http://www.ResilienceMatrix.com/ShipCaptainMedican.pdf
The Associated Notice with the Stores List
http://www.ResilienceMatrix.com/MedicalStores.pdf
Enjoy