* Sugar headed Northrop since 2003
* Company faces tanker contest re-run
* Successor sees opportunity in shipbuilding
* Northrop shares fall 1.7 pct after-hours (Adds further detail from interviews, analyst comment, share movement)
By Andrea Shalal-Esa
WASHINGTON, Sept 16 (Reuters) - Northrop Grumman Corp
Sugar, 61, presided over a period of strong growth at the
No. 3 Pentagon contractor but leaves as the company braces for
a re-run of a bruising $35-billion competition against Boeing
Co
He will vacate the chairman and CEO positions at the end of the year, but is staying on to advise the company until June 30 of next year.
Bush, 48, said Northrop was well-positioned given its focus on intelligence, surveillance and reconnaissance; unmanned systems; and cybersecurity -- three big areas of focus for the Pentagon.
Shipbuilding was recovering and likely the company's most promising area, said Bush who joined the company in 1987.
Bush said he wants to accelerate a drive to improve performance across the entire company, a maker of weapons ranging from nuclear-powered submarines to unmanned spyplanes.
Sugar spent 29 years with Los Angeles-based Northrop, and at Litton Industries and TRW, two companies later acquired by Northrop.
He told Reuters it was the "right time to hand the baton" to a younger generation of company leaders and was confident Bush and other top managers would continue the strong growth of the defense company.
Shares of Northrop dipped 1.7 percent in after-hours trade from their $49.85 close in regular trading on Wednesday.
Northrop's annual sales have grown to nearly $35 billion from $26 billion during Sugar's tenure as chief executive which began in 2003. The company also reversed a debt of $9 billion to achieve its highest ever credit rating.
SHIPBUILDING PROBLEMS
But Northrop has faced criticism this year over the performance of its shipbuilding business. At least two analysts downgraded the company's shares in July after it missed consensus estimates for second-quarter earnings.
The company has been working to correct quality issues in its U.S. Gulf Coast shipyards by making changes in production, engineering and testing. It recorded a $105 million pretax charge to its second quarter profit tied to increases in cost estimates to complete several ships.
Bush will become chief executive, and retain his title of president, effective January 1. Bush was also elected to the Northrop board of directors, effective immediately.
Lewis Coleman, now lead independent director, will become non-executive chairman effective January 1, the company said.
Defense analyst Loren Thompson said the succession should be a smooth one, given that Bush was Sugar's protege and had been groomed for the job.
Brian Ruttenbur, a defense analyst with Morgan Keegan, said resolving the shipbuilding problems and the management change "could be a very good thing for the stock in 2010."
He said the shipbuilding issue "has gotten progressively worse," but looked set to be resolved this year.
Northrop is the third largest U.S. defense contractor,
measured in prime contracts, behind Lockheed Martin Corp