Adding boats and prefabricated works to island defenses

What light forces and construction methods would support the island guns?

Use small boats and, if facilities permit, sheltered submarines, while bringing in guns first and using a wharf to support later construction.

Small armed boats would help prevent an attacker from concentrating freely around the islands. If sufficient construction equipment could be brought in, an enlarged sea cave might shelter one or two submarines. A substantial wharf would enable the deliveries needed for those later works. Six-inch guns and machine guns would still provide the first defences. Prefabricated pillboxes and concrete-block construction are proposed as ways to establish protection using methods available within the scenario.