Answer: Wood-Hulled Ships

The vast majority of the vessels in the U.S. Navy’s extensive fleets are metal through-and-through: battleships, destroyers, and aircraft carriers alike all sport nearly all metal construction and have for over a century.

There is an exception to the rule, however, and with good reason. The hulls of Avenger-class mine countermeasures ships are made of reinforced wood. The hull itself is Oak, Douglas Fir, and Nootka Cypress, selected for their high strength and flexibility but low weight; the wood is covered with a flexible coating of glass-reinforced plastic (fiberglass) to protect it from ocean water. The combination of the wood and plastic shell is well suited to bending and flexing under the stress of mine blasts without permanently deforming or caving in like a metal-sided vessel might. The design also provides the ships with a low magnetic signature.

The bulk of the Navy’s mine countermeasures ships are kept abroad in Japan and Bahrain where they can be easily deployed to keep foreign waters clear of mines.

Bonus Trivia: The Avenger-class ships are currently in the process of being replaced by Freedom and Independence-class littoral combat ships as well as other mine countermeasures platforms.