These two stamps demonstrate the height of waves. Storms can easily tear sails apart and break masts. Winds and waves are able to haul over ships to one side, often causing the cargo to slide. The cargo tied to the upper deck can be washed into the sea, superstructure and hatches severely damaged and anchor chains torn. It is possible to spring a leak and big ore carriers are subject to simply breaking apart.
Seas running over the decks represent grave danger for the life of seamen and passengers.
They could be washed over board or smashed against the superstructure. A strong storm can cause a ship to sink. On sailing-vessels you have to reef or salve the sails early to prevent such risks and dangers. The left stamp shows seamen salving their sails while a sea is washing upon the deck. Normally the topsails are the first to be salved, followed by the big main sails.