A powerful greatbow. Fires a heavy arrow long distances.
The Great Bow is a light, single-shot ranged weapon in RimWorld with slightly higher damage per shot, slightly longer time between shots, high accuracy, and slightly longer range.
Great bows aren't a weapon to be underestimated; while they still pale compared to modern firearms, tribals will often be equipped with them - and with the scale that tribal raids can get to, arrow swarms consisting greatly of great bow arrows are bound to happen, and skew any unlucky colonist or animal in sight. With a high and consistent accuracy, decent damage per shot, and decent range; the great bow is a decent (tribal) close-quarters weapon, but also an OK mid-ranged weapon - provided the shooter is capable of being accurate at around 24-28 tiles.
As its shots do 18 damage, that means that it can incapacitate an unarmoured human if a shot lands in their spine, but not to the point of causing permanent paralysis - unless they're a teenager. Additionally, shots to the limbs will be powerful enough to somewhat hinder their efficiency even against armoured opponents, which will affect their combat performance overall, and shots to unprotected teenage organs will destroy them.
Another advantage that the great bow has is that its considerable damage and range can be had for relatively little silver, so that makes them viable early-game weapons - or late-game tribal-only run weapons. It's advisable to equip somebody who has at least 97.5% shooting accuracy to efficiently utilise the great bow to its maximum range, which is achievable with a level 10 careful shooter, level 12 standard shooter, or level 16 trigger-happy. However, a minimum of 96% accuracy will suffice for efficient usage up to around 18-22 tiles. The great bow's DPS benefits most from the trigger-happy trait due to its longer warmup time than its cooldown.
Great bows can be purchased from neolithic war merchants, and from orbital combat suppliers - or obtained from incapacitated tribals. Great bows can also be manufactured at a smithy once the smithing research has been completed, for 50 wood and 18,000 (300 secs) of work.
Conclusion & Comparison
The great bow is a weapon that holds its own even against the pistol; the latter has slightly higher damage output than the great bow at touch range, but the great bow pulls ahead from 6 tiles onwards as its accuracy advantage kicks in - with the gap considerably extending in the great bow's favour. Therefore, the great bow is massively better than the short bow; it already starts off with a roughly 71.6% better damage output, and the lead widens to a staggering 192.1% in the great bow's favour at the short bow's maximum range of 29 tiles. While the great bow also has a significantly higher damage output than the pila, it lacks something that makes the pila a very competitive weapon: the ability to instantly remove limbs, decapitate, and destroy vital organs in one shot - and therefore the pila is much more likely to cripple or even instantly kill a human than the great bow is.
However, the bolt-action rifle is still a significantly better option than the great bow for mid-long range engagements due to its near-flawless accuracy, slightly shorter time between shots and longer range.
The great bow is most useful early-game for modern colonies, before researching Machining, or if you're low on metallic materials. It remains useful throughout the entire game for strict tribal-only runs.