At 24, Scott Fitzpatrick is the youngest of this year’s 40 Under 40 honorees, but don’t be fooled – he’s plenty serious about business.

He founded Shell Knob-based MariCorp U.S. as a small dock repair business in 2003, when he was just 15 years old. By 2006, the company had grown to six employees and annual revenues of $670,000.

After graduating from Cassville High School in 2006, Fitzpatrick headed to the University of Missouri-Columbia, and he continued to lead the company while earning his business management degree.

“When I graduated … in 2010 at age 22, the company had 30 employees and $4.5 million in revenue,” he says.

The company has grown to 42 employees and posted 2011 revenues of $6 million, which Fitzpatrick attributes primarily to commercial marina development in Missouri and several other states, including Oklahoma and New Mexico. Fitzpatrick’s business interests also include a role as 30 percent owner and director of LAD LLC, a company founded in 2011 to develop a marina in North Little Rock, Ark.

Fitzpatrick isn’t just focused on his own success, as he has helped two other entrepreneurs get started. One is an oil-change and carwash center in Holiday Island, Ark. The other is a floating restaurant on Table Rock Lake, for which Fitzpatrick financed a $30,000 line of credit so it could open last year. After it did, flooding struck, and could have kept the restaurant from opening, which Fitzpatrick says would have negatively impacted surrounding businesses.

“I provided an additional 100 feet of floating walkway for the restaurant at no cost so (it) could open and people could access it from shore,” he says.

That’s not the only instance in which Fitzpatrick helped his community. High lake levels in summer 2011 meant that Shell Knob’s Independence Day fireworks needed to be launched from a floating platform, but the entity that had agreed to build the platform backed out just a week prior to the event. The local chamber asked MariCorp to help – and Fitzpatrick led the company to assemble a 1,600-square foot platform on the holiday weekend.

A candidate in the running for a seat in the Missouri House of Representatives, Fitzpatrick’s other community endeavors include charitable donations and the creation of two $2,500 scholarships for Cassville High graduates.

Click here for full coverage of the 2012 40 Under 40.