A FLEET of 55 yachts, the second largest assembled, will contest the ninth edition of the biennial Dunhill San Fernando offshore race beginning on April 9. A record 60 boats contested the 1991 event which featured Whitbread Round The World Race contestant, Rothmans. The Humphries-designed 83-footer completed the 500-nautical mile dash across the China Sea to the coastal town of San Fernando in northern Luzon Island in a record two days, two hours and two minutes, an amazing 12 hours under Holland-designed ULDB Charley's 1987 record. It is most unlikely any of the 55 yachts nominated for the April 9 race will come close to the record. Richard Strompf will be looking for his second line honours victory in Hongkong offshore races in his 50-foot X-419, X-Rated. The cruiser-racer took line honours in last year's Corum China Sea Race from Hongkong to Manila. But weather conditions will play a crucial hand in the outcome of the race with the smaller craft favoured if the conditions turn light. Keith Jacobs' Dubois 44, Bimblegumbie, finished only 30 minutes behind X-Rated in the China Sea Race on elapsed time and has undergone extensive modifications in preparation for the race. With the demise of the IOR division, Jacobs has optimised the boat for IMS, modifying the hull, smoothing out the creases and attaching a bulb to the keel. ''Bimblegumbie is still one of the fastest boats in the world in the right conditions,'' warned Jacobs who took line honours in 1989 and took IOR on handicap in 1991 denying Rothmans the line honours-corrected time double. Frank Pong's Castro 40, Jelik, will campaign in CHS for corrected time honours but still remains a strong contender for line honours. She finished literally minutes behind the bigger X-Rated last year in the China Sea Race. Dr Ian Nicholson's Banner 41, Intrigue, has been bedeviled by bad luck recently with a mast collapse the latest catastrophe. But if the all-weather racer's experienced crew can keep the gear intact, she will also be a top contender for line and handicap honours. This year's race will feature a large number of new entries and skippers. making their first crossing at the helm. Only one overseas competitor will take on the large Hongkong contingent - Jocelyn Hess' brand new Beneteau 440, Talisman, which will be based at the Manila Yacht Club. Skippered by George Hackett, it will be the boat's maiden voyage.