This was my experience with US records: I had a stack of Discharge Certificates (example attached, from the SS Texaco Oklahoma). It shows where travel began and ended, but it doesn't show every stop along the way. Based on the dates, I requested Ship Movement Cards with the names of the ships and the dates my father was on board. (Example attached - same dates highlighted.) Although the Discharge Certificate indicates the place of shipment [outbound] and the place of discharge [inbound] as New York City, you'll see the Ship Movement card shows the trip was from NYC to Aruba to NYC.
While the records MAY be lost, I would definitely suggest that you make inquiries.
Also, please post (or send me a message containing) the ship names and dates of travel. I may be able to find corresponding information in the Genealogy Bank or Fold3 newspaper archives (papers frequently listed arrivals and departures, and even cargo, during peacetime).
I also found this link for Finding Seafarers on Crew Lists: http://www.crewlist.org.uk/findingoncrewlists.html
(for British-registered vessels).
Hope this helps!