Short voyages
There is a 1/100 chance to spawn a large chest, a 1/20 chance to spawn a medium chest, and a 1/20 chance to spawn a small chest.[2] Assuming the number of Taijitu in the chest is uniformly random, short voyages yield an average of 0.28 Taijitu, so taking short voyages averages 17.86 supplies per Taijitu (the best).
Medium voyages
There is a 1/50 chance to spawn a large chest, a 3/50 chance to spawn a medium chest, and a 13/100 chance to spawn a small chest. Assuming the number of Taijitu in the chest is uniformly random, medium voyages yield an average of 0.485 Taijitu, so taking medium voyages averages 24.74 supplies per Taijitu.
Long voyages
There is a 3/50 chance to spawn a large chest, a 9/100 chance to spawn a medium chest, and a 17/100 chance to spawn a small chest. Assuming the number of Taijitu in the chest is uniformly random, long voyages yield an average of 0.855 Taijitu, so taking long voyages averages 23.39 supplies per Taijitu.
Source:https://runescape.fandom.com/wiki/Treasure_chest_(Uncharted_Isles)
02-Jul-2019 00:53:53