The first entry is always the pin's source. Overall confidence is a weighted average of how firmly each reference supports the start and end times used above; a reference counts half as much for every 180 days older than the newest.
Allseas[3]' own fleet page states Solitaire has operated "since her launch in 1998"; only the year is documented, not an exact day.
Wikipedia corroborates the Swan Hunter conversion and 1998/99 entry into pipelaying service.
Allseas' own fleet page states the vessel has been in pipelay service since its 1998 launch.
Something missing or wrong? Say it in your own words: a link that backs this pin up, a different start or end date and why, or a fact it lacks or gets wrong. The AI checks it against this pin's sources, searches for better ones, and adds any page that backs you up. The pin's own sources still count most.