ABU DHABI, United Arab Emirates - Williams, nine times a Constructors' champion F1 team, remains optimistic despite having a terrible 2011 Abu Dhabi GP.For the first time - or at least as far back as co-founder Patrick Head can remember - the Williams' cars started at the back of the grid; neither Rubens Barrichello nor Pastor Maldonado scored a point.That made Abu Dhabi the sixth consecutive blank sheet in a dire season in which the team has scored only five points from 18 races. In the previous points system, Williams would have scored zero.TECHNICAL CHANGESHead, chairman Adam Parr and Barrichello refused to be downcast. Head said: "Fundamentally the car is too weak and, unusually, we've been unable to improve during the year but I'm very confident that, with new senior technical staff, we will turn that around. Already major progress is being made on next year's car."I'm very confident we'll dig ourselves out but when you're in a season like this... it's obviously extremely stressful for everybody."Williams will switch from Cosworth to Renault power - the same engines that drive championship winner Red Bull - and has had management changes: technical director Sam Michael has departed.Parr said the new team of technical director Mike Coughlan, aerodynamics head Jason Somerville and chief operations engineer Mark Gillan was already showing huge potential. "We have realised there are some quite profound failings in the way we have been doing things but they're not going to be fixed overnight."We are being more realistic about where we are and where we need to be. I feel very energised - the people here are stunning, without exception."MADE A 'HUGE ERROR'Barrichello, 39 and whose future beyond the Brazilan season-ender is uncertain with the team having talked to 2007 champion Kimi Raikkonen, agreed morale was improving. "On the engine side... I don't know if it's going to be a winning car but it's going to be a hell of a lot better."Parr said Williams had made "a huge error of resourcing and judgement" in concentrating on a new gearbox rather than the exhausts and mapping systems that teams such as Red Bull had exploited to such telling effect.Head refused to point a finger at any one area, however, even if Williams was the only team to have exceeded its engine quota in 2011 and picked up a penalty for it. He said: "What's disappointing for everybody, Sam included, is that we were really determined to make a big step forward in 2011 year and a lot of very hard work and effort was put in... some quite bold steps were taken."Ultimately the overall sum was far from where it needed to be."