A trip from Sydney to Melbourne for one ride on a cold, wet Sunday at Sandown always looked like a questionable gamble for Sydney jockey Blake Shinn.

It turned out to be a disaster.

Shinn, who copped two suspensions amounting to 27 meetings at Warwick Farm on Saturday, rode first-starter Magdalena's Rose for his stepfather Lee Hope in the Jim Conway Handicap - and was duly rubbed out for another 14.

The Melbourne stewards found Shinn guilty of careless riding on Magdalena's Rose who was having her first start and finished sixth of seven.

The suspensions, which begin on July 18, must be served cumulatively leaving Shinn on the sidelines until August 29.

While Shinn's day could hardly have been worse, Dwayne Dunn dominated the flat racing program at Sandown with a treble of winners for five trainers.

Dunn scored on Crystal River in the Jim Conway Handicap and High Aims in the Alannah Hill Handicap for the David Feek and David Brideoake training partnership and on Brian's Honour for Michael, Wayne, and John Hawkes in the Sportingbet Handicap.