This is a copy & paste, but it's good info. I see lots of people on this site claiming they have a layout boat for sale and it's a sneak or marsh boat. Just cause you can lay in it doesn't mark it a layout boat. :)
Duck Boats 101
Duck hunting literature contains volumes on guns, decoys, dogs, calls and calling, blinds, and techniques. Amazingly enough though, very little attention is given to boats for duck hunting. This is surprising because most hunting situations require a boat. This section of my web page seeks to give a very brief introduction to duck boats from bygone days as well as boats available today.
During the days of market hunting duck hunting was big business. Professional waterfowlers developed many highly specialized boats for their chosen trade. It should be noted that not all boats used for duck hunting are duck boats. A duck boat by definition is a boat developed for the primary purpose of hunting. Today's modern jon boats are often used as duck hunting boats, but by no means are they duck boats.
Some of the more famous duck boats developed by the market hunters include:
Barnegat Bay Sneakbox
Senachwine Iron Skiff
Hennepin Duck Boat
Monitor Marsh Boat
Koshkonong Flat Boat
Merrymeeting Grass Boat
Novia Scotia Duck Tub
Most of these highly specialized boats vanished as a result of outlawing market gunning. Today there only exists a handful of manufacturers producing true duck boats. Today's duck boats can loosely be placed into six categories.
Boat/Blind Combination (not derived from market hunting)
Layout boats are a very specialized gunning boat. Typically, they are towed or piggy-backed into place by a larger boat, called a tender. Most often used for hunting divers, they are positioned in close proximity to a large spead of decoys in open water. Those that hunt from layout boats often claim no method for hunting divers is more effective.
Sneak boats are more versatile than layout boats. A common use for them is sneaking up on rafting diving ducks. Hence the name sneak boat. Typically the hunter will set out a large spread of decoys in open water. He will then row upwind and anchor. When a suitable number of ducks have decoyed the anchor is lifted and the wind pushes the boat within gunning range of the ducks. Many claim this method is particularly effective on canvasbacks who are less skittish on the water than bluebills.
Marsh boats are small boats whose source of power is the paddle. The class includes hunting kayaks, pirogues and other small boats that typically hold at most two hunters. They are sometimes called skiffs. Their strengths include light weight and portability. They can be carried or pulled to remote spots where bigger boats have no access. They easily slip through shallow water and can be used to jump shoot ducks. Care must be taken when shooting out of one because they can be tippy. Sometimes they are the perfect tool for bagging a limit when ducks are using smaller out of the way waters.
The duck skiff is essential equipment when hunters need to travel great distances over open water while carrying substantial amounts of gear. Typically they're 14 feet or longer and use a 25 hp or bigger outboard motor. Their attributes include seaworthiness, stability, and capacity. In addition to a means of transportation, they can be hunted from. Most duck hunters utilize a jon boat in the role of a duck skiff. Quite simply, they are the workhorse for waterfowlers.
The scull is a highly specialized boat. Sculling for ducks, almost a lost art, is gaining popularity. The scull boat is propelled by means of a long oar that extends out from the transom. The operator lays down in the boat and applies a rotating motion with the oar. This pushes the boat forward at a mild pace which doesn't alarm ducks. Once in range, the sculler raises and shoots his quarry. I've heard scullers claim that they're able to scull into a raft of ducks, part the raft, and have the raft close back after passing through. Now that would be sight!
Boat blinds have come into their own since the days of market hunting. Offering features similar to the duck skiff, with the added ability to conceal several hunters in comfort, has made them desirable in the eyes of duck hunters in all four flyways. As an outgrowth of jon boat blinds they continue to evolve into a specialized boat that combines concealment, carrying capacity, and comfort.