While the United States Navy has not used the flying boat in a long time, other countries have kept these planes around. After all, they do have some advantages in a military setting. You can't exactly ground them by bombing a runway, it's easy to re-deploy them to a new forward base, and flying boats are versatile assets – just look at the PBY Catalina.
One of the countries that is keeping the flying boat alive is China. This country operated the Harbin SH-5 flying boat as a maritime patrol and search-and-rescue asset. It has a top speed of 345 miles per hour and a range of just under 3,000 miles, according to MilitaryFactory.com. It can carry 13,000 pounds of bombs, missiles, or torpedoes. The Chinese only built seven of these planes, and FlightGlobal.com notes that three are still in service.
Harbin SH-5 seaplane. (Wikimedia Commons)
China has not stopped with the SH-5. According to a report by CNBC.com, the AG600, a four-engine flying boat roughly the size of the 737 has just made its first flight. Officially, the aircraft is intended to carry out firefighting and search-and-rescue missions. MilitaryFactory.com reports that has a top speed of 311 miles per hour and a range of just over 2,700 miles. So far, at least 17 airframes have been ordered.
Some Chinese media outlets are reporting the AG600 – or a variant – could be useful for military operations in the South China Sea. China has been building "unsinkable aircraft carriers" in the maritime flashpoint, enabling the People's Liberation Army Navy and People's Liberation Army Air Force to operate fighters in the area. This sort of development prompted the United States military to retire its flying boats.
Two artists's impressions of the AG-600. (AVIC graphic)
China's continued pursuit of flying boats could be seen as a hedge against the United States being able to disable the island bases in the South China Sea. The AG600 does have the capability to haul cargo and specialists to either repair a base, or to maintain a presence until a base can be fixed.