Who attacks the steamboat as it approaches the Inner Station? Why?
As Marlow travels down the river towards Kurtz's Inner Station, their steamboat is attacked by African natives. Interestingly, Marlow notices that the natives are only shooting small arrows the size of twigs at the steamboat in an attempt to scare them away and halt their journey. Unfortunately, the Helmsman is fatally wounded when a spear strikes him in his side during the attack. In the middle of the ambush, Marlow cleverly blows the steam whistle, which scares the natives, who immediately retreat back into the forest. After arriving at the Inner Station, Marlow and his crew are introduced to a Russian known as the Harlequin, who informs them that Kurtz had ordered the natives to attack the steamboat. The Russian tells Marlow that sometimes Kurtz hated the idea of leaving the Inner Station and returning to civilization. Essentially, Kurtz enjoys ruling as a tyrant in the depths of the wilderness without having to answer for his questionable, immoral practices. Kurtz also understands the competitive, jealous nature of the businessmen working for the Company and realizes that they want to remove him from his station.
As the steamboat progresses down the fog-covered river, the vessel is attacked by a barrage of flying arrows. Marlow spots a strange face in the brush on the riverbank and soon realizes that the land is covered with African natives prepared to launch a full attack. Although the crew manning the boat attempts to fight back with guns, their efforts are mostly fruitless, and blood spills across the boat's deck. The helmsman dies in the attack, and the agent is forced to take over the steering of the boat.
Ultimately, it is revealed that the African natives did not attack the boat impulsively; rather, Kurtz--who was paranoid that the Company wanted to remove him from his station and have him killed--ordered the natives to attack the boat in order to protect his own position.
As Marlow's steamship approaches the inner station in a heavy fog, arrows begin to fly out from the jungle. The "pilgrims," or white passengers, fire blindly into the jungle with their rifles. Marlow blows the steam whistle on the ship and scares off the attackers. Then Marlow realizes the helmsman has been killed. In the next chapter the Russian explains that the Africans attacked the ship because they were afraid the ship was coming to take Kurtz away from them. Later the Russian divulges that Kurtz ordered the attack himself because he did not want to be taken away from his base of power.