Georgia Tennant who took to the waves with her famous father Peter Davison.MORE: David Tennant and wife Georgia treat son to unbelievable Zelda themed birthday cakeJoining the pair was Georgia's brother, Louis, who celebrated his birthday over the weekend.WATCH: Georgia Tennant shares incredible video of parents singing Happy BirthdayGeorgia uploaded several snaps from the family excursion, as well as a small clip of Doctor Who star Peter steering them down the river.And to mark her brother's