Here we call those Float Tubes and don't really consider them to be boats, but they are handy for fishing in more remote places where you have to hike in. Nice to have though.
So have we one of Jakes pic's is on the Swannee, and we have not seen any sturgeon either, thank goodness just plenty of snake's turtles and gators. A man here was drinking, and a moccasin was swimming next to some kids in the river, he swam up grabbed the snake and it bit him a few times, he was dead before the ambulance got to him. My mother got bit by a rattler in Stone Mountain and almost lost her leg. She still had the scar's on her leg when she passed 50 years later. I was the oldest so I always had the task of caring for mama's bites, bullet hole from 9mm to the chest,etc. so when I got injured, I pretty much took care of it myself.
I've heard them referred to as "belly boats." That's what I searched on, although the design of a true belly boat is more that just a tube with a sling seat. In the right conditions, they're a blast.
I've watched a few shows about invasive species, on the discovery channel where they are taking over rivers and such, so I can relate to what you're talking about. I think it's good when people step up and thin out invasive species.
That sounds like y'all were busy, making them, and were fixing to expand to kayaks and canoes to me. No photo huh? I worked with fiberglass and a bunch on corvettes, and boats so know what it's like to work with them.
That's something, I think most of the time, they're just hunting for food or whatever and will leave you alone if you let them.
I recall when the fiberglass Vettes first came out. I was in downtown DC and heard a loud SMASH! I looked up and someone had rear-ended a Vette that was sitting at a red light...cracked it open like an egg.
I found our old Larson to be a great boat, and we took a lot of people out on it, even to the ocean on occasion too. Sounds like your father was a smart man. Our son was a sailor in the Navy, and did very well in the Navy, got Sailor of 1/4 and Sailor of the year award. "Very Proud of him".