LYNN – Dock work and other Seaport Landing Marina improvements planned for this winter and spring could top $1 million and cap off the largest-scale project undertaken in the marina, said city officials, since its construction three decades ago.?The average marina in New England lasts eight to 10 years without a major rebuild. We?ve been here 25,” said city Harbormaster Jim Perry.Perry?s office window overlooks Seaport Landing with its empty docks encased in ice. The city spent $1 million last year replacing four docks and driving new piles. Perry said the new docks are heavier with more weight below the waterline to resist destructive winds that whip across 12 miles of open ocean south of Lynn before striking the marina.?They?re bigger, stronger, heavier,” he said.Owned by the city with 160 slips available to boaters, Seaport Landing is a weekend, often season-long, summer recreation destination for 300 marine lovers.City purchasing officials open bids on Feb. 6 for the marina?s second round of renovations, with bidders required to outline proposals for replacing the fuel dock, including new pumps and a dockhouse.Perry said fuel was not available in the marina last year, forcing boaters to gas up at Point of Pines in Revere, or other marinas, including Salem and Boston Harbor facilities. He said boating to Boston to fill up requires burning roughly 12 gallons of fuel.City officials have identified $400,000 to pay for the fuel dock replacement. An additional $1 million – if it can be found – will pay to replace the marina main dock and “A” dock – the last of five docks connected to the main one still requiring replacement.?B, C, D and E have already been done. A is in very tough shape,” said Community Development Facilities Manager John Moberger.Bid requirements specify the fuel dock?s completion by May 23 with “A” dock completed by Aug. 1 and the main dock by Oct. 24.Marina work requirements listed in bid documents include removing and disposing of existing marina floats, removing timber piles and installing new steel pilings and timbers as well as floats.Perry said Seaport Landing improvements translate into economic benefits for the city with boaters spending money in local restaurants and grocery stores, and buying fuel and marine hardware.He said the renovations also parallel work on the Blossom Street landing ferry terminal and proposals for docks to be built along with future development at the South Harbor waterfront site near the General Edwards Bridge.?What it means for the future is having a stable environment to boat from,” Perry said.