A tugboat chief engineer who killed his drunken captain while trying to defend himself from a knife attack on deck was jailed for 15 months yesterday. Yang Wenyu, 48, described the captain as a 'fierce and cruel desperado' who used prostitutes and had once invited his crew to stake their lives on a game of poker. The jail term should lead to mainlander Yang being released almost immediately, due to time off for good behaviour and the 10 months he has already served while awaiting trial. Yang, who worked on tugs bringing containers from Zhuhai, pleaded guilty to manslaughter at the Court of First Instance. Mr Justice Azizul Suffiad said he accepted the engineer had been acting under severe provocation when he lashed out at the knife-wielding captain with an iron bar. The killing of captain Wu Jiangjun, 43, while the boat was in the Yau Ma Tei typhoon shelter on October 2 last year, was sparked by Yang's determination to protect the vessel's engine. Wu, who was drunk, was trying to move the boat sideways by 'gunning the engine', changing quickly from forward to reverse gear. Yang said: 'The exhaust pipe released black smoke as if a nuclear bomb had exploded.' But when he remonstrated with Wu, the captain told him: 'It is my ship. What do you think you are?' Yang said the captain slapped him violently. 'I was shocked by his attack and my mind went blank. Since he was much taller and stronger than me, I was completely at a loss, in fear,' he said. Wu then grabbed a 20cm fruit knife and chased Yang to the bow of the boat from where he could not escape. He described dodging the captain's lunges with the knife and then, in desperation, striking him on the neck with the bar. Wu crashed to the deck, smashing his head against a table as he fell, suffering a fatal head injury. Yang threw the knife into the water. Describing the captain, Yang said: 'He was a complete desperado. He slept with prostitutes every time he went on shore.' He described how Wu had once shunned the idea of playing poker for the price of a meal and, banging his fist on the table, suggested the crew gamble with their lives instead. Michael Gerber, defending, said that by contrast Yang was an honourable family man with a wife and three children waiting anxiously for him to return to the mainland.