The relief sculptures by <a href="//commons.wikimedia.org/wiki/Creator:Charles_Wheeler_(sculptor)" title="Creator:Charles Wheeler (sculptor)">Charles Wheeler</a> in the sunken garden at the Tower Hill memorial, commemorating the merchant mariners who lost their lives in World War II. 
This images shows the first three reliefs (counting clockwise from the west).
<a href="//commons.wikimedia.org/wiki/User:Thryduulf" title="User:Thryduulf">Thryduulf</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>