wrecks in Truk lagoon which have largely disintegrated.
In fact some of the aircraft wrecks in Truk are still amazingly intact. I have dived them several times, up to as recently as 6 months ago.
The Betty bomber and Emily flying boat have obviously been subject to many visits by divers plus the elements over many decades. However, the only significant change I have observed over the past 5 years is that the faint red "rising sun" marking on the wing of the Emily is no longer visible.
The Zeke's (Navy Zero's) inside the hold on the Fujikawa Maru are showing some recent damage. Divers climbing into the cockpits etc have dislodged the seats etc. However, paint markings such as tail numbers are still visible after 78 years under water.
Although Truk is obviously warm water, there are generally no strong currents and since it is almost on the equator, there are no Typhoons. The policing of the wrecks and remnants over the past 15 years or so has also had a beneficial effect with preservation. The biggest effect over the past 5 years, has been a spread of algae over several of the shallow wrecks.