Ramming as an allegedly obsolete naval tactic

What naval weapon or tactic was declared obsolete but has proved useful again?

Ramming is the example, with Icelandic fisheries vessels and South China Sea confrontations cited as evidence of its continued use.

Ramming is the naval counterpart suggested to the continued use of bayonet charges on land. Icelandic fisheries vessels provide one example of ships still using physical collision against other vessels. Encounters involving fisheries vessels in the South China Sea provide another. The answer concerns the survival of the tactic, without proposing a return to purpose-built ram warships.