A DHC-3 Otter float plane and a Cessna 180 float plane were converging courses towards the same seaplane base near Squaw Lake, Canada. The Cessna overtook and passed the Otter on the right, then crossed in front to establish a right-hand circuit to the lake. The pilot of the Cessna transmitted a landing intention, which the Otter pilot interpreted as a bay in front of the company’s base. The Otter pilot did not pay attention to the Cessna, and the Cessna turned to the same converging approach course. After four to five seconds, the Otter’s left float struck the Cessna’s right wing and cowling. The Otter overturned and sank. The Cessna’s right wing and cowling were damaged, but the aircraft remained afloat with no injuries.A DHC-3 Otter float plane and a Cessna 180 float plane were converging courses towards the same seaplane base near Squaw Lake, Canada. The Cessna overtook and passed the Otter on the right, then crossed in front to establish a right-hand circuit to the lake. The pilot of the Cessna transmitted a landing intention, which the Otter pilot interpreted as a bay in front of the company’s base. The Otter pilot did not pay attention to the Cessna, and the Cessna turned to the same converging approach course. After four to five seconds, the Otter’s left float struck the Cessna’s right wing and cowling. The Otter overturned and sank. The Cessna’s right wing and cowling were damaged, but the aircraft remained afloat with no injuries.