Within a few months, the self-taught shipwright found work at a shipyard, founded his own business and sent word for his family in Kauai to join him.
By 1958, Iwamoto bought the East 16th Street property for his fledgling catamaran business, where it weathered economic dips and flourished without any help of paid advertising.
Iwamoto's skilled hands spoke for themselves.
"He had an ability to work with wood," said his oldest son, Wayne Iwamoto, 60, who bought the business in 1983. "He had an ability to create unusual shapes out of wood and build designs that were lightweight and strong."
Many of Iwamoto's boats have competed and placed multiple years in the Los Angeles-to-Honolulu Transpacific Yacht Race.
"He rarely got the praise from the people he built the boats from as much as he should have," said John Conser, a close friend to Iwamoto for more than 30 years. "He was very quiet and not at all egotistical …They don't have anyone like that anymore. They broke the mold when they made him."
Clad most often in a white sailor's cap and blue work shirt, Iwamoto could still be found climbing ships' ladders, tools in hand, up to a few months before his death.
Perhaps most surprising — at least to those who did not know him — was that Iwamoto did that despite being legally blind.
After losing most of his sight in the mid-1980s and selling his business to his eldest son, Iwamoto's passion for building boats did not waiver.
Iwamoto wanted to teach the craft in an institutional setting back in Hawaii, but was turned away due to a lack of a formal higher education. Instead, he channeled his passion for the craft into mentoring the many shipwrights who passed through his yard.
"He had honestly, high work ethic — everything about him was right," Conser said. "He made it on his own back and hardworking hands, and didn't accept money from anyone. If we had a world full of Iwamotos, everything would be just fine."
He is survived by his eldest son Wayne and two younger children, Carol, 55, and David, 50. Iwamoto's wife, Grace, died in 2008 at age 88 after more than 60 years of marriage.
His family is planning a private memorial in Hawaii.