Double and triple check your wall for tiny breaches, especially where it crosses uneven land. At the water's edge, make sure the wall extends as far out to sea as possible.
As a last resort, I discovered on several occasions that I couldn't get a secure seal at the water's edge. Instead, I built a full wall all the way around before I could get my security rating to rise. (A hassle, I know, but it worked!)
Author, playwright, and lecturer, New York City
Lead Writer, Reverie World Studios, (2008 - present)
Director of Voice Acting, Reverie World Studios, (2014 - present)[This message has been edited by Gordon Farrell (edited 07-27-2016 @ 04:01 AM).]