California Yacht Owner Threatens to Kill Dock Worker in Vicious Showdown

A California yacht owner's vicious beef with a dock worker has reached death-threat levels -- and their exchange was caught on camera and included a nude, and very rude, gesture!

Check out the clip ... it all unfolds when San Diego entrepreneur Ajay Thakore swings by the swanky Marriott Marquis Marina in his rare $4.5M Tecnomar for Lamborghini 63 yacht to pick up one of his employees -- but things boil over when dock worker Joseph Holt tells him he can't be there.

Thakore, the CEO of medical advertising firm Doctor Multimedia, flips out on Holt big time ... and starts spewing threats like, "I will kill you, you know I will kill you, I will kill."

And it doesn't stop there -- as Thakore's pulling out of the harbor, he drops trou to make a full frontal salute in Holt's direction. Stay classy, San Diego!

Holt's only retaliation was flipping the bird, and he later told CBS8 that was all he could do to keep his cool and avoid escalating the situation.

Holt says parts of the altercation were not captured on camera, and he adds ... Thakore not only threatened to kill him, but also claimed to have connections who could totally mess up his life.

Holt also says Thakore pulled out $100 bills and tossed them at him, even chucking some in the water.

BTW, Thakore's done some backpedaling since the ugly exchange -- he now says, "The interaction that occurred yesterday was regrettable. What started as a minor misunderstanding escalated into an argument, and I apologize for my actions and to those who witnessed the unfortunate exchange."

FWIW ... One of Thakore’s employees claims the whole thing began because other dock workers blocked him from boarding the yacht.