Ship's access to fresh water, you'd say level with strand (4,4)

'ship's access to fresh water you'd' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'level with strand' is the wordplay.
'level with' becomes 'tide' (I can't justify this - if you can you should believe this answer much more).
'strand' becomes 'lock' (I've seen this before).
'tide'+'lock'='TIDE-LOCK'

'say' is the link.

Can you help me to learn more?