haha..saw it again funny .. but actually if you think abt it .. is very good deterrant idea against oncoming enemy amphibious landing forces.
At low tide get a excavator and dig down 2meter deep and 4meter wide all along the strip you are defending then wait for incoming tide to fill it back up again with sand and water which makes very soft fast sinking mud.
When amphibious forces land the minute they jump off their boats with all their heavy gear they sink, rifles become clogged with dirt most will not operate very well.
Light vehicles come in also sink along with the men in a ClusterFuck Mass Orgy makes them prime stationary targets for our waiting machine gunners.

I ever kanna before, walking over a plank carrying my 84, fell in to some really stinking sinking mud, the more you try to get out the more you sink and get stuck..really frustrating.