During winter the Manxman will have a limit on the number of people on-board.

Whilst the capacity of the vessel is 948, the Steam Packet will allow 750 people on each sailing.

The limit is due to the vessel having an alternative safety system.

James Royston, fleet operations manager at the Steam Packet, explained: ‘In the design development of the ship, the original design had lifeboats and life rafts on it like Ben-My-Chree.’

However, in conversations with the Classification Society, an organisation that establishes and maintains technical standards for the construction and operation of ships, it was discussed that a Marine Evacuation System (MES) would be a more efficient safety system.

This sees passengers evacuate through a slide into life rafts, and is the safety system that the Manannan uses.

But a set of international safety standards called the Safety of Life at Sea (SOLAS) requires for vessels to have lifeboats and life rafts.

Manannan, as it is a high-speed craft, falls under a separate set of regulations which allows for the MES on the vessel, without any additional risk assessment.

Mr Royston said that the Marine Evacuation System is the quickest way to get passengers off the vessel.

He said: ‘There is a regulation in SOLAS that allows you to apply for an alternative design arrangement, so if you can prove that the system that you are going to use is as safe as what is required under the rules then you can do it.

‘We went through this process, part of it is a hazard identification workshop where you look at all the possibilities of situations and eliminate them all.

‘When the Marine Evacuation System did its heavy weather testing, it was tested in conditions up to 4.1 metres of significant wave height.

‘What was brought up is you don’t know if the system would work above 4.1 metres of wave

‘Lifeboats are only tested up to three metres, but because we had identified a potential hazard, we had to act on it.

‘On a ship you have a windward side and a leeward side, the leeward side always has a lot less weight than the windward side because the ship acts as a barrier, creating a calmer area of water in the shelter of the ship’s side.

‘The conditions would be much lower on the leeward side, meaning that even in five or six metre waves, the leeward side will always be in less than 4.1 metre waves.

‘The reason for the winter capacity limit is because we know that with 750 people, we can evacuate them all from one side of the ship.’

He said that it is a self-imposed limit to mitigate the hazard identified, which would only happen between November and March.

However, if it is a calm day, and there is a need to go over that limit, then the captain can undertake a risk assessment, and depending on the result allow for more people on the vessel.

Asked why Manxman has a capacity of 958 when it is limited for half the year, Mr Royston said: ‘It is because of the Strategic Sea Services Agreement [issued by the Department of Infrastructure] that specified that it had to be bigger than Ben-My-Chree.

‘But there is demand for a few periods of time for that larger capacity, like during TT, Grand Prix and some of the summer holidays.’

In the winters from 2017 to 2020, records showed that the maximum recorded passenger figure was 539.