Using the same overall configuration of the earlier and highly successful DHC2 Beaver, the Otter is much larger overall. The Otter began life as the King Beaver, but compared to the Beaver is longer, has greater span wings, and is much heavier. Seating in the main cabin is for 10 or 11, whereas the Beaver could seat six. Power is supplied by a 450-kW (600-hp) Pratt & Whitney R1340 Wasp radial. Like the Beaver, the Otter can be fitted with skis and floats. The amphibious floatplane Otter features a unique four-unit retractable undercarriage, with the wheels retracting into the floats.