Michigan Seaplane Base (41D) is a public-use seaplane base serving White Lake, Michigan, at 980 feet above sea level, with CTAF 120.5. Its lanes: 09W/27W (2,006 × 200 ft, water); 12W/30W (3,688 × 200 ft, water); 13W/31W (2,618 × 200 ft, water); 14W/32W (4,530 × 200 ft, water); 18W/36W (3,515 × 200 ft, water).
This diagram plots every lane from the FAA’s surveyed threshold coordinates, so they sit at true heading and true length — a gift for the pilots, students, instructors and families of 41D.