The Fire and Rescue Service's inshore lifeboat, the RNLI's St Helier all-weather lifeboat and the States police all responded to the incident, which unfolded in the 'small roads', just east of Elizabeth Castle.
According to Jersey Coastguard, two people were onboard when the fire broke out onboard the vessel – J67 Ocean Blue – but are understood to have been able to escape unharmed.
Fernando Carvahlo from Aqua-Mar Fisheries was working on Victoria Pier when the fire started.
He said: 'The boat was completely alight, the all-weather lifeboat was out almost straight away and the inshore lifeboat went out too but there was nothing they could do. It is absolutely burnt out.
'There were a lot of flames and black smoke – I would say that it went up about 40 metres high.'