USCGC Blackthorn (WLB-391) was a 180-foot sea going buoy tender (WLB). Blackthorn was initially assigned to the Great Lakes for ice-breaking duties, but after only a few months, she was reassigned to San Pedro, California and served in San Pedro for several years before being brought into the Gulf Coast region to serve in Mobile, Alabama then Galveston, Texas. In 1979-1980, Blackthorn underwent a major overhaul in Tampa, Florida and upon completion was outward bound from Tampa Bay on the night of January 28, 1980. Meanwhile the tanker Capricorn was standing into the bay. The captain was on the bridge, but a junior officer had the conn. Having been overtaken by the Russian passenger ship Kazakhstan, Blackthorn continued almost in mid-channel. The brightly lit passenger vessel obscured the ability of the crews of Blackthorn and Capricorn to see each other. Capricorn began to turn left, but this would not allow the ships to pass port-to-port. Unable to make radio contact with the tender, Capricorn’s pilot blew two short whistle blasts to have the ships pass starboard-to-starboard. With the officer of the deck confused in regard to the standard operating procedure, Blackthorn’s Captain issued orders for evasive action. Though collision was imminent, initial damage was not extensive however, Capricorn’s anchor was ready for letting go. The anchor became embedded in the tender’s hull and ripped open the port side. Just seconds after the slack in the anchor chain became taut, Blackthorn capsized. Six off-duty personnel who had mustered when they heard the collision alarm were trapped in the skin of the ship. Several crew members who had just reported aboard tried to escape and in the process trapped themselves in the engine room. Though 27 crewmen survived the collision, 23 perished.
| Name | Rating | Duty Station | Date |
| Hall, C. | SA | USCGC Blackthorn | 1/28/1980 |
| Estrada, D. M. | DC2 | USCGC Blackthorn | 1/28/1980 |
| Maxcy, D. R. | MK1 | USCGC Blackthorn | 1/28/1980 |
| Frank, D. R. | SS3 | USCGC Blackthorn | 1/28/1980 |
| Sindelar, E. F. | Em3 | USCGC Blackthorn | 1/28/1980 |
| Crumly, G. W. | QM2 | USCGC Blackthorn | 1/28/1980 |
| Rovolis, G. Jr. | SA | USCGC Blackthorn | 1/28/1980 |
| Harrison, G. E. | SA | USCGC Blackthorn | 1/28/1980 |
| Roberts, J. J. | CWO | USCGC Blackthorn | 1/28/1980 |
| Ressler, J. | ET1 | USCGC Blackthorn | 1/28/1980 |
| Prosko, J. E. | SA | USCGC Blackthorn | 1/28/1980 |
| Frye, L. D. | DC3 | USCGC Blackthorn | 1/28/1980 |
| Stidham, L. O. | MKC | USCGC Blackthorn | 1/28/1980 |
| Luke, M. K. | FA | USCGC Blackthorn | 1/28/1980 |
| Barnaby, R. B. | SNGM | USCGC Blackthorn | 1/28/1980 |
| Boone, R. D. | MK2 | USCGC Blackthorn | 1/28/1980 |
| Gauld, R. W. | QM3 | USCGC Blackthorn | 1/28/1980 |
| Avila, S. | SS1 | USCGC Blackthorn | 1/28/1980 |
| Faulkner, R. R. | EM2 | USCGC Blackthorn | 1/28/1980 |
| Brewer, W. R. | SA | USCGC Blackthorn | 1/28/1980 |
| Flores, W. R. | SA | USCGC Blackthorn | 1/28/1980 |
| Lafond, B. | MK1 | USCGC Blackthorn | 1/28/1980 |