For those that cant find it, its just outside rohendel (2 ships outside) in the harbor.
the thing is , its not always there as they rotate the ships. If its not there you can talk to the other "fishing" ship and see how long it is until it ends it's sale (can see it in the exchange menu (top right) when it times out and despawns a new ship will spawn a few minutes after so you can get your anchor (5k sceptrum's coin)