MARBLEHEAD-Public Works Director Dana Snow is reaching for his hat and coat n very, very slowly.In a letter made public by the selectmen at their last meeting, Snow said that he plans to retire. The date he chose is March 26, 2010. He has been employed by the town for 37 years, including the past 25 years as head of the water and sewer department.He joked over the phone Friday that he got the superintendent?s job in August 1983 because “People thought I was older,” blaming that on a lack of hair, but his four years in the Air Force, including a year aboard a C-130 transport plane in Vietnam may also have had something to do with it. His salary last year was $104,068, making him the town?s fifth highest-paid employee.Nineteen months ago n March 26, 2007 n he became head of the highway department as well when the departments merged to become the town?s department of public works.?I was in the right place at the right time,” he said, summing up his career so far. “It?s been quite a ride and I?m grateful for all the support I received.”?I announced my retirement in advance to give people time to factor the change into the budget,” Snow said. “I prepare a budget and I know people need time to plan.”He made it clear that the announcement won?t affect his performance. The timing gives him one more winter on his watch after this one and he said he?ll give the town “100 percent.”And as far as he is concerned, retirement from town employment will probably just mean a change of jobs n but he noted that whatever he does on March 27, 2009 will probably not require a lot of 2 a.m. phone calls.?I like to walk in the snow, as opposed to driving a truck in it or working in a garage,” he said. He admitted that on snowy nights, like many of us, he may be looking out the window, wondering where the plows are.