RE: I want to build a duck boat like this
If you want a boat of this fashion then I suggest you get a scull boat. Not the garbage that comes from the East coast, but a real Humboldt Bay original. They can be used as a layout or sculled right up on birds like an old log. They're the deadliest thing ever designed for waterfowl. Seeing is believing. Do a search for scull boats and you'll probably come up with all kinds of stuff, but you want the low profile boats that originated out of Humboldt county on the west coast.