Supertankers time-chartered by Japan's oil refiners are facing a challenging situation, changing the basic mechanism of crude trade by doing ship-to-ship, or STS, transfer in Malaysia, even as some of them are partially idle due to disruption at the Strait of Hormuz, while others are tapping the US market, several tanker brokers, owners and charterers told Platts, part of S&P Global Energy, June 9.