The fire broke out on Monday evening - around 5.35pm - according to Khalifa Al Muhairi, Chairman, RAK Fishermen Association.
"The fire was due to a diesel leak," he claimed.
Two fishermen were on board when the blaze broke out, he added.
"The two fishermen, working with an Emirati captain, were heading from the fishing port in Al Geer area to the fishing port in Shaam."
Recounting the incident, he said that one of the two fishermen was starting the boat after fueling it up, he explained. "An electric short circuit sparked a fire in the diesel that had leaked into the boat while fueling up."
The motorboat exploded due to the fire, Al Muhairi elaborated.
"One of the two fishermen sustained serious injuries and burns in the incident."
The RAK Civil Defence rushed to the scene of the fire after being alerted, putting it out using water and foam.
"The injured fisherman was shifted to the nearest hospital for treatment and medical care," Al Muhairi further said.
He called for a regular maintenance of motorboats to avoid such incidents in the future.
"The sweltering summer heat adds to the risk of fires and explosions."