On September 6, 1999, about 1830 Alaska daylight time, a float equipped Cessna 180 airplane, N5316D, sustained substantial damage when it did not become airborne during takeoff and collided with level terrain at the end of the Shannon's Pond seaplane base, Dillingham, Alaska. The accident occurred at 59 degrees 03.54 minutes north latitude, 158 degrees 34.63 minutes west longitude. The commercial pilot and the one passenger on board were not injured. The visual flight rules (VFR) personal flight was being conducted under 14 CFR Part 91 by the airplane's owner. The flight was departing for the Tikchik Lakes, Alaska. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. During a telephone interview with the NTSB investigator-in-charge (IIC) on September 8, and in his NTSB Pilot/Operator report, the pilot stated he water taxied to the southwest end of the 1,400 feet long by 100 feet wide, northeast-southwest water lane and began the takeoff run. He said the winds were north about four knots, and the water surface was lightly rippled. The flaps were set to 20 degrees. The pilot indicated that the airplane came up "on step" normally, but did not lift off the water before colliding with the northeast end of the lake. The airplane came to rest several hundred feet beyond the lake edge, and sustained substantial damage to several fuselage stringers aft of the rear float attachments. The pilot stated that the airplane contained full standard fuel tanks, about 100 pounds of equipment, and that he and the passenger weigh 450 pounds combined. He stated in his Pilot/Operator report that he could have managed his fuel better. The allowable maximum takeoff weight for the airplane is 2,820 pounds. The NTSB IIC estimated the actual takeoff weight to be 2,813 pounds. The Cessna 180A pilot operating handbook states the takeoff water run on floats, at 2,820 pounds is 1,356 feet with zero knots of headwind.