Both men were tourists and on their way home in a trimaran from a sailing competition in Norway, says prosecutor Maria Thorell.
According to the suspect, they had participated in some sailing competition where they had competed together and were now on their way home, she says.
Then they became enemies and the whole thing resulted in the victim's death.
The Gothenburg District Court decided on Sunday to detain the man on probable cause suspected of murder.
Maria Thorell does not want to provide any further details about the incident.
I don't want to go into details. The man is being detained because we have so much evidence that it is probable cause for him to have killed the victim.
The man denies the crime, says his lawyer Fredrik Zenngard, who does not want to comment on what his client has explained about what happened.
I don't want to anticipate anything, but the investigation must take its course, says Zenngard to TT.
The alarm on Thursday came in as a boat accident at sea in the Kattegatt in Öckerö municipality, about 25 kilometers off the outermost islands in the Gothenburg archipelago.
In a major rescue effort, the man was winched up from the sea. He was taken to hospital by ambulance helicopter, but his life could not be saved. Later it emerged that the incident was being investigated as a murder and that the other man had been arrested.
