He looks through the logbook and handover book, checks the weather conditions and forecast, signs any relevant documents, and gives the assigned vessel and its equipment a quick once over.

Mr Tse will then assemble the full crew - chief officer, second officer, chief engineer three cabin attendants and three sailors - to brief them on any significant developments and emphasise, as always, the need to regard vessel and passenger safety as paramount.

'We need to communicate before we get on board and ensure we fully understand the roles we each play,' he said. '[In particular], if a good mutual understanding exists between the chief officer and the captain, the chance of accidents is very low.'

He added, though, that with jetfoils reaching speeds of up to 40 knots, and with so many other vessels operating in the South China coastal waters, tight controls and rigorous training were essential. The Marine Department, for instance, stipulates working hours and rest periods for officers that are very similar to airline pilots and cabin crew.

This means a maximum eight hours on duty during a night shift, as opposed to 11 during the day, and having two full days off after working two consecutive nights. Rostering on either day or night shifts is usually rotated every three months. Besides that, chief officers, aiming to become master mariners qualified to command at night, receive special training and have to acquire the necessary years of experience. It involves not just the usual courses, examinations and licences administered by the Marine Department, but also at least three years as a master mariner on the day shift before being eligible for promotion.

Night service training entails classroom sessions, supervised practice, and on-board observation for about a month under the eye of the training master. The company does the intermediate assessments and the Marine Department then conducts a final review and test.

Naturally, a key part of the training is familiarisation with any recent enhancement to the vision augmentation, or night vision, system. In the normal course of operations, it is the second officer's responsibility to monitor this, but senior officers obviously still have to know everything about the technicalities, range and accuracy of the readings.

'Regardless of the shift, operating a jetfoil requires a high level of teamwork,' Mr Tse said. 'The master mariner has to process all the information gathered from the other officers, make judgments and decide what action needs to be taken, especially if an unexpected incident occurs at sea.' Each decision or judgment is guided by a combination of factors. At one level, there are the harbour regulations for Hong Kong and Macau dictating, for example, a speed limit of 15 knots once past the Green Island buoy inbound or 12 knots beyond the inner buoy when approaching Macau. At another, there are the 'rules of the road' for seafaring in coastal waters, the prevailing weather and traffic conditions, and whatever experience or common sense convey.

'Under any circumstances, the captain has the final say and is the ultimate decision maker in full control of the jetfoil,' Mr Tse said.

That, of course, refers not just to navigation, communication and berthing but also to dealing with rowdy or disruptive passengers.

Though comparatively rare, a losing streak on the tables or one nightcap too many can lead to unruly behaviour, and this must be dealt with firmly and effectively.

On certain occasions, since officers should not leave the control room while a jetfoil is under power, Mr Tse has had to shut down the engines and intervene. One such case involved a man attempting to force open a door while threatening to jump out and commit suicide. He then tried to strangle the second officer with his tie.

'It turned out the man was a gambler who had lost huge amounts of money at a casino,' Mr Tse said. 'He had been escorted on board and the last thing he wanted was to be forced back to Hong Kong, so I steered the vessel back to Macau. In cases like that, I usually don't need to settle the matter. The chief and second officers will report to me via an intercom system. If I decide to return to the place of departure, then I will make an announcement to the other passengers, explain what happened, and let them know what is being done is for the safety of everyone.'

If there is an altercation between passengers, the crew's first step is to separate the protagonists, speak to them individually and, if necessary, make it clear the police will be there on arrival. Depending on passenger numbers and scheduling, Mr Tse can expect to complete three or four round trips per shift. Despite the inherent pressures, he now almost prefers working nights to days. In part because he is in full control, in contrast to daytime voyages when the chief officer will take turns at the wheel and the master mariner's role is more to supervise or offer occasional advice.

He also admits to rather enjoying the tranquillity found in the midst of a night crossing when fewer ships are around.

'Sea traffic peaks from four to seven in the evening and gets less busy after nine,' he said. 'The quiet environment usually gives me peace of mind and allows me to concentrate on steering the vessel.'

Now, in his 60s, Mr Tse has been at sea in one capacity or another since signing on as a cadet with a British shipping company 40-plus years ago.

In 1972, he joined the Far East Hydrofoil Company as a deck officer and then moved to Shun Tak as a chief officer in 1990. From the outset, night watches were a requirement, simply accepted as a routine, unavoidable part of the job.

Looking ahead, he noted that anyone completing the three-year full-time higher diploma offered by the Maritime Services Training Institute at the Vocational Training Council would be set for a successful career with a jetfoil operator.

Shun Tak, for example, now employs more than 100 staff qualified as master mariners and expects to keep adding to its fleet of 31 vessels.

'It used to take a second officer at least 10 years to become a master mariner but, with a growing number of vessels and fewer young people willing to get into the industry, the time now needed has been shortened to five to six years,' he said.

This is the seventh in our eight-part series on people who work at night

All at sea

After a recent change to the on-board menu, Mr Tse realised - not for the first time - how hard it was to please some passengers. One regular late-night traveller asked for a bowl of his favourite noodles from the 'old' menu and handed the exact payment to the cabin attendant. On hearing it was no longer available, he refused to accept his money back, said his mood and appetite were ruined, threatened to sue the attendant and demanded punitive compensation from the company.