Preparation - Those arriving early will stake out the area to be used and make absolutely certain that our area is above the high tide mark for the day yet close enough to the ocean to minimize the carrying distance for water. Be sure to stretch out before you start shovelling and carrying water. When lifting buckets of sea water or sand remember to use your legs and not your back. SWaPing - the key to structual integrity, longevity and ease of sculpting. SWaP is an acronym for Shovel, Water and Pack.
Most pros recommend very wet sand, ie three parts water to one part sand.
We'll start by watering down the base, digging the moat, and making large wet mounds where the walls, turrets and main towers of the castle will go. Molds - this is where the large bottomless containers come in. Sand is Shovelled into the container, Watered and Packed by walking and stomping on it. When it is as firm as possible, you add more sand, more water, and pack until the container is full and the sand is hard-packed. This process is repeated until a mound of the height desired is reached.