On August 05, 2019, the towing vessel Mangilao was under tow by the towing vessel Chamorro, about 800 miles northwest of Guam in the Pacific Ocean, en route to a drydock in Subic Bay, Philippines, in a developing storm. The towline to the unmanned Mangilao parted, and the vessels separated. The Chamorro retraced its route and found the Mangilao taking on water, and the Mangilao eventually sank. The Chamorro continued to the Philippines with its crew of 10. No pollution or injuries were reported. The Mangilao was lost, with an estimated value of $437,227.​

The ​​probable cause of the sinking of the Mangilao was the failure of the Chamorro’s towing arrangement due to the loss of a towline shackle pin, which left the Mangilao adrift and resulted in the ingress of water from boarding seas in a developing typhoon.