A new method for clearing the Wharf St boat ramp of silt is being trialled on the Whanganui River.
A cutter suction dredge has been working at the boat ramp this week to clear 1-1.5m of silt off the river floor.
Port manager Phil McBride said a silt build-up had made the slipway sometimes impassable for boats at low tide.
But the main concern was the Coastguard, which needed to be able to get out at all times.
A digger sits on a barge digging up silt, which is pumped out into the river channel to be carried out to sea by the outgoing tide.