https://www.bbc.co.uk/news/uk-england-hampshire-54684440

This is odd. Father Anon used to work on oil tankers. He advised there is no way it took 10 days to suddenly find stowaways. There is limited space available, and crew would cover all of it on a daily basis. Nowhere to hide.

Apparently only way on would be single access ladder, and would be easy to monitor.