SEOUL, Sept 17 (Reuters) - South Korea's Hyundai Heavy Industries saw its shares open up 85% from their initial public offering (IPO) price on their trading debut on Friday.

The shipbuilder, one of the largest in the world, raised $935 million from its IPO, with much of the proceeds set to fund investments in new technology.

(Reporting by Joyce Lee and Jihoon Lee; Editing by Jacqueline Wong)