Small Aircraft; High Wing; 1 Eng; Fixed Gear
Flight Crew Private
Flight Crew Last 90 Days 20; Flight Crew Total 80; Flight Crew Type 20
Training / Qualification; Situational Awareness
Ground Event / Encounter Other / Unknown
Aircraft Aircraft Damaged
Human Factors; Weather; Environment - Non Weather Related
[My] seaplane landed long and touching down past the target beamed point with added forward momentum that extended the stop point. [This] resulted [in] impact with a pontoon boat and damages to floats.  Started a second path over the lake as a downwind path over the far right of the long side of the lake to review boat traffic and evaluate wind and water conditions. After identifying a target landing path of over 2500 ft and touchdown point then started my base to final turn and lined up with high trees to my right and LVR (Landing Visual Reference). As I descended below the tree line with 10-degree flaps and following procedure to evaluate my altitude over water with peripheral vision and manage sink rate at the time of the flare when reaching ground effect. A target of landing within 1000 ft and maintain 300 to 500 added distance to taxi forward to a sandbar where many boats set up. The weather condition; hot; humid; with light variable wind; possible wind changes to a tailwind; alignment to a straight wall of tall trees on the right side where the beamed target point was harder to recognize below the tree line. [The] high [and] somewhat narrow terrain around this lake made spacing left/right during approach important to a straight landing path.
GA pilot reported low speed contact with pontoon boat after a water landing.