Boomakers Shy At Coconut Bookmakers fear a major gamble may develop on Aidan O´Brien´s Coconut Beach in tomorrow´s totesport Chester Cup following the Irish trainer´s brilliant Guineas double at the weekend. O´Brien has never had a runner on the Roodee before, and the lightly-raced four-year-old, the mount of Kieren Fallon, is a fascinating contender for the historic event over two laps of the tight circuit. Coconut Beach is saddled with just 8st 5lb and ran solidly enough on his seasonal reappearance when finishing fifth under top weight at the Curragh. He had previously been unbeaten in two runs last year and is now as short as 5-1 joint-favourite from 14-1 with William Hill. The other favourite, Swift Sailor, was one of a maximum field of 18 to stand their ground at yesterday´s final declaration stage. Mark Johnston´s unexposed four-year-old has also had only three career outings and opened his account this season when winning a Musselburgh handicap in March. He will be partnered by Kevin Darley, who will waste down to 8st 3lb to take the mount. Johnston said: 'He´s a very inexperienced horse for the Chester Cup but he´s done nothing wrong. He worked the other day and he worked very well.' ? PA Sport