The expanded pontoon system, which should be in place in time for Easter, is designed to allow the safe transfer of foot passengers from small ferries and water taxis.
Previous arrangements had been criticised as passengers were forced to climb wet ladders up to the Commercial Quay.
The new pontoon’s position has angered the last two professional fisherman who use the quay, as they have been told to use a different area and give up their traditional mooring rights.
‘This move will make our lives sheer hell, and it is hard enough as it is,’ said Lewis Main, skipper of Amanda Jane, and Dave Gillingham jnr, of the Katie C.
The pair used social media to invite residents to the Commercial Quay to explain their dilemma.
‘We don’t want to make a lot of noise or complain and we’ve had a huge amount of local support,’ said Mr Main.
‘But the rest of the quay where we have been told to moor has no easy access for loading and unloading. We already have to lower 500kg of pot bait every morning by ropes and there is only an old ladder to access the boats.’
The fishermen have been told they could use other parts of the quay for loading, but they say these are unsuitable in certain winds.
‘There is no issue or problems with other fishermen, the Harbour Authority or States members or anything personal,’ Mr Main wrote on Facebook.
‘It’s just a case of getting a point across that ours is an industry that is dying and we need help as much as the ferry and everyone else. All we want is to be treated fairly’
The pair are asking the General Services Committee to install new ladders and safety rails if the boats are forced to move.
General Services Committee chairwoman Lin Maurice said the decision to install the new pontoon was made primarily as a health and safety measure.
‘For that reason it is money well spent.’
Harbour authorities said that local fishermen have been kept informed by Ms Maurice and the harbour team.
‘There are no allocated permanent moorings on the Commercial Quay,’ she said.
‘The fishermen have their own permanent moorings in either the inner or outer harbour. An additional tyre fender will be placed on berth number three to mitigate the loss of space for loading and unloading caused by the introduction of the pontoon.’
The new 16m-long pontoon is to be fixed to the southern end of commercial berth number one, where it will join to the base of the existing dinghy pontoon with an access bridge.
The pontoon is currently being built in Guernsey, at a cost of £159,000, before being shipped to Alderney.