Go to the map Makin. Then go to the spot right beside the huge tower.

Go out in the water, to the fish fence, and then throw about 4-6 satchel charges as close to the fish fence as possible.

After that go a little bit back, one or to people need to be ready with a grenade.
Throw the grenades on the place where you planted the satchel charges and watch this big wave come in!

Note: may not work all the time...