Marine A-frame cranes are commonly used for various tasks, including:
Loading and unloading equipment and supplies from ships or barges.
Handling containers and heavy cargo during offshore construction projects.
Launching and recovering smaller boats or submersibles.
Installing and maintaining offshore structures like wind turbines or oil drilling rigs.
Assisting with underwater operations, such as lifting and positioning underwater pipelines or structures.

These cranes are usually operated by trained personnel and are subject to strict safety regulations to ensure safe and efficient operations in marine environments.