Jeong Kim, 39, is a former Navy officer who spent seven years aboard nuclear attack submarines.

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The number of attack submarines in the undersea fleet fell to barely 50 boats.

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"It does raise the question of why we need 10 carrier battle groups and close to 100 attack submarines, " he said.

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Cruise missiles can be launched from naval attack submarines or from bombers.

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In particular, the panel proposed increasing the size of the Navy to 346 ships, including 11 aircraft carriers and 55 attack submarines.

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These will be coordinated with a force of about 50 attack submarines.

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It has also built nuclear-powered ballistic missile and attack submarines.

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China has bought 12 Russian Kilo-class diesel attack submarines.

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Some frigates provide air-defence, while others hunt for hostile submarines that might attack them.

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But, it says, the UK's ballistic missile submarines should now be converted to an attack fleet and equipped with conventionally armed cruise missiles.

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