Captain Paul Watson is the Founder of non-profit marine conservation group Sea Shepherd which uses direct action to protect marine life and expose illegal activities on the high seas. He launched the ship with Teri Irwin in December 2007.
He described captaining the M/Y Steve Irwin - which was part of a fleet of 11 vessels and multiple small boats - as 'an honor'.
'No longer safe'
"The lives we have saved and the difference we have made with this vessel has been awesome," he added in a statement.
"We worked the ship hard, through horrific storms and crushing ice and after 11 years, our engineers have determined that the Steve Irwin is no longer safe for sea."
Leading Neptune's Army
The M/Y Steve Irwin was built in 1975 and served as an enforcement patrol boat for the Scottish Fisheries Protection Agency for nearly 30 years.
After being acquired by Sea Shepherd, it was initially named the MY Robert Hunter, after the Canadian environmentalist who co-founded Greenpeace, but was renamed in honor of the host of the TV wildlife documentary series The Crocodile Hunter, Steve Irwin, who died in September 2006 on location in Queensland, Australia.
In addition to helping to save more than 6,000 whales from the illegal Japanese whaling fleet, the vessel has also seen action protecting pilot whales in the Faroe Islands, the Mediterranean bluefin tuna and humpback whales off Australia's Kimberley coast.
The organization's Board of Directors decided to retire the 59-meter-long flagship after a recent assessment revealed issues that could have put the crew at risk if the vessel was allowed to continue to lead Sea Shepherd's fleet. For its final journey, the M/Y Steve Irwin will make its way to a recycling facility.
"In line with Sea Shepherd's environmental ethics and standards the Irwin will be recycled," said Sea Shepherd Australia's Jeff Hansen.
"Together with the Steve Irwin, we have made history, saving hundreds of thousands of marine animals in defense of our oceans, humanity's primary life support."
The M/Y Steve Irwin's flagship status will now pass to the M/Y Ocean Warrior.