(August 7, 2018, 12:19 PM EDT) -- FORSYTH, Mo. — The three daughters of a couple who died July 19 when an amphibious vehicle known as a “duck boat” sank on a Missouri lake filed suit on July 30 against the operators of the vessels. They argue that the defendants disregarded storm warnings and a history of safety issues with duck boats (Michelle Chaffer, et al. v. Ride the Ducks International LLC, et al., No. 1846-CC00143, Mo. Cir., Taney Co.)....