Oil tanker markets are again knocking at price barriers with year-highs expected to tumble as demand exceeds supply of modern ships, brokers were reporting. Shortages of high quality oil company approved vessels were causing rates to peak for Suezmaxes in the Mediterranean and West Africa and for Suezmaxes in the North Sea. July cargo demand for VLCCs in the Middle East was also seen possibly puncturing previous highs for the year. Strong demand from Western loading areas could deplete a potential 68 vessels available in the Middle East, of which just half were modern, broker E.A. Gibson said in a report. "(This) should contribute to a further upturn in rates," the broker said. Westbound VLCC rates have remained stable all week at W87.5-90 ($15.50 per ton) for the U.S. Gulf.