User blog comment:Rulebladeraysawa/Why trinity force isnt "core" on GP/@comment-4834593-20120831210034/@comment-189.70.250.75-20120903163508

Actually...

 Gangplank's   Parrrley : The entire damage including its bonus damage component can critically strike.

http://leagueoflegends.wikia.com/wiki/Critical_strike#Champion_abilities