Despite obstacles that have complicated construction and driven up costs, work to transform State Pier in New London into an offshore wind hub is about 75% complete and on schedule to achieve “substantial completion” by February, Connecticut Port Authority Executive Director Ulysses Hammond announced on Tuesday. Hammond, addressing the authority’s board of directors at its regular meeting, said there remain challenges as workers make a final push towards project completion in anticipation of the pier accommodating offshore wind vessels in the spring that are associated with the construction of South Fork Wind. The cost of the project, which has risen dramatically since it was first proposed, now stands at $255.5 million. Costs are split between the state, which has contributed $178 million, and offshore wind partners Orsted and Eversource, who are jointly providing $77.5 million towards the project. The added costs were in part associated with excavation work as crews work to drive piles and install retaining walls around the expanded pier.