Breakwalls and groynes are large rock structures built offshore into a body of water to protect breachfront real estate and water access points against significant wave uprush. Breakwalls are often used for marina and harbour inlets to provide a calm transition for boating traffic. Groynes are often used for preserving beachfront, where they extend into the water and often curl to protect against the prevailing wind direction. Breakwalls and groynes are typically built from water access using barges, platforms and tugboats.