HONGKONG'S elite windsurfers Sam Wong Tak-sum, Ken Wong Hop-hei and their woman teammate Lee Lai-shan will be put to test on new sail boards when they travel to Europe next month for four major championships. The International Yacht Racing Union has replaced the Lechner boards with Mistrals at major competitions this year and Hongkong coach Rene Appel is eager to see how his top charges perform with the new equipment. Dutchman Appel said: ''In theory, the new boards should benefit the smaller-built Asian competitors because they are two kilograms lighter and easier for a lightweight person to control. ''I think our sailors should do very well with the Mistrals and it would be interesting to see how thet fare at the four European regattas.'' The trio will be competing in the SPA Regatta in the Netherlands, the UK Eurolymp at Hayling Island in England, the Kiel Week Regatta in Germany and the IMCO European Championship in Belgium before coming back to Hongkong in July. They will have an extra incentive to do well on this tour as it was announced yesterday that the Windsurfing Association of Hongkong has created a new award scheme offering cash prizes for top three finishes at world ranking events. Under the Mobil Pacesetter Award, any Hongkong boardsailor who comes first in a world ranking regatta will receive $5,000. The runner-up will get $3,000 and a third-place finish will be worth $2,000. Meanwhile, the opening leg of the six-regatta Mobil Hongkong Circuit will be held this weekend at Tung Wan off Cheung Chau island. The territory's world class trio of Sam Wong, Ken Wong and Lee are expected to dominate but they will miss two events of the series because of international commitments. They will not be in Hongkong for the Tolo Championships at Tai Mei Tuk in Taipo on June 12 and 13 because they are still in Europe. And they will also miss the final leg of the circuit, the Stanley Championships on December 4 and 5, as they are in New Zealand for the IYRU World Cup. Appel said: ''Their absence from two of the six regattas can only make the Mobil series all the more interesting and throws the overall championship wide open. ''But any one of them can still clinch the title if they perform well in all four competitions they are entering because only the best five results are counted in the final standings.''