Visiting New York City last week with his family, 11-year-old Orange County middle schooler Carson Kropfl rode his skateboard boldly into Trump Tower.

The San Clemente surfer/skater passed calmly through security, rode around some more, located a Trump Tower napkin at the Trump Bar and scrawled a personal note on it for President-elect Donald Trump. Carson's parents Keith and Carrie Kropfl stood back and recorded his escapade on video.

"Dear Mr President," the note said, "your son needs one of my Locker Board skateboards to skate the White House. Can I send him one? Shred hard, Carson."

Kropfl, whose first day of middle school had convinced him last northern autumn that there must be a market for a mini skateboard that can fit into a sixth-grader's backpack and locker, has become the inventor of the Locker Board.

Just in case the new leader of the free world hasn't seen one of Carson's YouTube videos, Carson scribbled his website lockerboard.net on the napkin, leaving the note with one of Trump's security personnel.

Carson said this week that he hasn't heard back from the president-elect, yet, but that may be understandable. "He's got a few other things he's working on," Carrie Kropfl said.

Carson, however, has built five Locker Boards with Trump's youngest son Barron – who is about his age – in mind. The Kropfls wonder which colour is Barron's favourite. Carson said he is prepared to ship one to the White House.

Visiting Trump Tower wasn't actually the Kropfl family's reason for flying to the Big Apple. Fox TV's Harry Connick Jr had discovered the Locker Board online and invited Carson and his parents to New York – air and hotel paid – so Carson could appear on the Harry Show as a "Biz Kid to Be".

Carson didn't realise it until he got into the studio, but he was in competition that day with two other entrants for a $US10,000 ($13,200) prize and a $US50,000 branding package.

Although his Locker Board sales pitch was trumped by another team, he came home with a $US1000 consolation prize, a Motorola camera phone and newfound reinforcement that he is onto something good.

On the day after the show was taped, Carson was skating through Central Park when he rolled up to a man on a bench holding a big snake – maybe a python. The man wrapped it around Carson's neck. The boy got a little nervous, handing the man his Locker Board. The Central Park personality's reaction was priceless.

'No! You're the Locker Board kid!'

"No!" he proclaimed. "You're the Locker Board kid that's on the news!"

On Monday, Carson was back at home, surrounded by Shorecliffs Middle School classmates in the den to watch his appearance on the Harry Show and share his joy.

His friends own Locker Boards. They remember when Carson's parents had told him he needed to do chores to earn money to pay for his surf contest fees and surf lessons. "I hate doing chores," he'd said at the time.

That was when he decided to pursue in earnest his idea for a locker-sized skateboard.

He collected used skateboard decks. He experimented shaving them down into various shapes until he found one that proved surprisingly easy to ride. He could even do kick flips on them.

With help from his mum, he launched a website. An Orange County Register article generated nationwide responses. Carson's YouTube videos sent the buzz worldwide.

He initially recycled skateboard decks to sell for $US20, then began installing trucks and wheels on them so he could sell a complete Locker Board for $US99. The biggest challenge was finding enough donated old decks to keep up with demand.

Carson said he has sold about 125 Locker Boards so far, has shipped them nationwide, has donated 30 boards to charities and has netted a profit of $US2700. He is donating 10 per cent to the Positive Vibe Warriors Foundation run by San Clemente pro surfing brothers Dane, Patrick and Tanner Gudauskas.

Carson's 2017 goal, he said, was to build the brand, partner with a manufacturer to produce a fully fabricated version to sell alongside his recycled decks, and "inspire kids to work hard, shred hard, dream hard and play hard".

Oh, and there's the small matter of getting a Locker Board into Barron Trump's hands. Carrie Kropfl thinks it could happen.

"I had no idea any of this would happen," she said. "I didn't even think he would get into Trump Tower. Who knows? You might as well try, right?"