|The attack on the Card was quite successful|
USS Card was an Escort Carrier - a small aircraft carrier with a small complement of aircraft, primarily intended to provide air support for convoys of merchant ships. She served this role quite successfully in the North Atlantic in World War II, battling German submarines and sinking nearly a dozen of them in three cruises as the flagship of Task Group 21.14 in 1943.
After WWII, she was decommissioned, but in 1958 was recommissioned as a Utility Carrier (CVU). By that time she could no longer support air operations - the jet aircraft of the day required catapults to launch - but was still useful for transporting fully assembled aircraft across the ocean. As USNS Card, she was operating with a civilian crew under the Military Sea Transportation Service, and was soon designated to ship combat aircraft to the burgeoning buildup in South Vietnam.
Tied up alongside the pier in Saigon Harbor, she made an enticing target. And sure enough, Viet Cong irregulars led by Lam Son Nao swam out to the ship with two large explosives, planted them on her hull outside the engine compartment, and returned to shore safely. They both exploded, killing five sailors and ripping a huge hole in the hull, flooding the engine room and sending the ship to the bottom.
Although the Viet Cong celebrated the attack as a great victory, the Americans refused to acknowledge the sinking, claiming the Card was only damaged. They dispatched a team of US Navy divers led by founding Navy SEAL Roy Boehm, and in an amazing feat of engineering, they were able to re-float the ship in only 17 days. At that point she was towed to Subic Bay for repairs, and she re-entered service in December. USNS Card was ultimately retired from service and scrapped in 1970.
There's no grand point to make here - this is just a piece of US Naval history that very few Americans know. Although it IS a reminder that for all their own destructive capacity, aircraft carriers are huge and vulnerable. The US doesn't typically fight wars against modern first world near-peer competitors with 21st century weapons, but you can rest assured if at some point we DO go to war against a modern, capable force we will certainly lose one, and probably more than one carrier.