The Duckworth Navigator Sport 20 2013 is a deep-V design and the Duckworth Pro 721 2013 is a modified-V design, so you're likely deciding between two noticeably different on-water experiences. Hull type shapes everything from ride quality and fuel burn to dock handling and resale trajectory.
On paper these two are close siblings in the size department - Duckworth Navigator Sport 20 2013 at 20,3 ft versus Duckworth Pro 721 2013 at 21,0 ft. At 1 600 lbs and 1 600 lbs respectively, both sit in a similar weight class - either should pair comfortably with most mid-size SUVs and half-ton trucks, though always confirm your specific tow rating with the motor added.
The Duckworth Navigator Sport 20 2013 carries a rated maximum of 150 hp. Engine data for the Duckworth Pro 721 2013 wasn't available in our records - check the manufacturer's spec sheet before sizing a motor.Both carry nearly identical fuel loads - 42 gal and 42 gal - so range won't be a tiebreaker here.
Both boats are rated for 6 passengers - a good fit for a family of four or five plus guests. Comfort at capacity is another matter; the longer hull typically means more seat options and better weight distribution.
Bottom line: The Duckworth Navigator Sport 20 2013 and Duckworth Pro 721 2013 are closely matched on the specs that matter most. Test-ride both on the water you actually use, check current dealer pricing, and factor in long-term service access before you sign.