On January 19, 1997, about 2030 Pacific standard time, N42376, a Cessna 180J, operated by the owner/pilot, collided with trees while maneuvering and impacted water near Lopez, Washington. The airplane was substantially damaged and sank. The airline transport pilot and his passenger escaped from the airplane and received minor injuries. Instrument meteorological conditions prevailed and no flight plan had been filed. The personal flight departed from a private airstrip near Lopez and was destined for Monroe, Washington. The flight was conducted under 14 CFR 91. According to the pilot, he listened to the Automatic Terminal Information Service (ATIS) recording from the Whidbey Island Naval Air Station, located about 7 nautical miles southeast of the departure airstrip, just prior to departure. He stated that the ATIS reported 900 feet scattered cloud sky conditions, a 1,100-foot broken cloud ceiling, and "good visibility below." Dark night conditions prevailed. He also stated that he attempted to contact the Seattle Automated Flight Service Stations via radio on the ground and received no response. The pilot did not receive a weather briefing prior to the flight. He decided to take off from the private airstrip, known as the Decatur Shores Community Airstrip, after a "normal' engine run-up and verification that the airplane's vacuum system was "checked OK." The pilot further stated: Immediately after takeoff (at 100 - 150 feet [above the ground], estimated) I went into solid cloud very unexpectedly. Held heading, lowered nose slightly to avoid stall, and attempted to read rate-of-climb, in lower left side of panel. Attitude indicator seemed wrong. Switched overhead light on to read rate-of-climb, which seemed low. Pulled nose up to increase climb angle, noticed glow of lights below through cloud, realized I was not where I wanted to be, and simultaneously felt a double thump as we hit something.... Engine was only producing low power even though I visually checked throttle position and it was fully forward. Felt slight stall and recovered. Still in cloud and unable to see. Engine was running smoothly, but not much power....Water suddenly appeared...we hit water in level attitude. The pilot did not report any preimpact mechanical deficiencies in the NTSB Pilot/Operator Aircraft Accident form (attached) that he submitted to the Safety Board, and he also indicated that he should "...not fly at night unless good weather is a certainty" in the "Recommendation" section of the form.