Different SUP Types
SUPs are still relatively new (compared to canoes and kayaks) to recreational paddling. They come in two broad types based on the shape of the board - displacement and planing. Choosing one or the other is the first big decision you’ll want to make.
Displacement hulls: An easy way to identify a displacement hull is to look at the front - if the nose of the board is pointed and doesn’t curve up, it’s a displacement board. Displacement boards are designed to cut through the water, pushing the water to the side to maximize efficiency - covering the most distance with the least amount of paddling energy. Displacement boards are best suited for paddling on flat water, in the rivers, lakes and marshes, especially where there isn’t surf or waves to help push you along. One thing to note - to help increase their efficiency, displacement boards tend to be narrower and longer than planing hulls. This makes them a bit more tippy for beginners/occasional paddlers. Try the board to get a feel and realize that practice helps make them more stable.
Planing hulls: Planing hulls look like oversized surf boards, which is one reason people like them. The nose is generally rounded and curves up, the board is wider and has more volume. All of this is designed so as the board picks up speed it will gradually rise on top of the water (“on plane”), reducing drag and increasing speed. Their width and volume also makes them more stable. This all adds up to great performance once the board is up “on plane”. The challenge is that a wave assist is required to get there - humans don’t have the power to overcome the resistance created by the bow wave under the up turned nose by ourselves. Waves and surf provide the added push needed. So planning hulls look like big surf boards because that’s what their designed for - paddling in waves and surf. On flat water, their performance varies, but in general requires more effort to go the same distance as a displacement hull. For purely recreational use the additional stability can offset the lowered efficiency, particularly if the board is primarily being used for activities like yoga and local fishing.
Focus on displacement boards
If you’re paddling flat water - lakes, rivers, marshes - especially if you like going long (more than a few hours) or going fast, or both.
If you're going tripping (folks use them on the Maine Island Trail)
Focus on planing boards
If you like paddling in the surf and waves
If stability is at the top of the list (new to the sport, fishing, yoga, leaving at the lake for guests, etc.)
There are a few categories of SUP you may have heard referred to (as in "you should get a touring board"). These are just a way of defining the hull types by purpose. The category names aren't really ideal, because they are either to general or too narrow, but the most common are:
Touring: This is what most of the displacement boards are. It is an efficient hull design that cuts through the water well, and is therefore good for touring. But don't feel like you need to be going on long voyages to have a touring board. Around us they are the perfect board for paddling through the salt marshes or along the coast.
Surf: A short, rounder planing hull. Designed for turning in the waves, they can be lots of fun. A hard-core surf SUP is not much good for other types of paddling, but hybrid models can offer good performance in and out of the surf.
All Around: The catch-all name for planing hulls with an emphasis on stability and ease of use. They vary in size to fit different people, and can hybridize with surf, fishing or touring. A good board for relaxed paddling, letting the kids play on and using at the dock or beach.
There are also some other categories beyond the big three:
Race/exercise: A long and lean displacement hull. The emphasis is on speed and efficiency over stability.
Fishing: A big planing board to give optimal stability. Also incorporates features to allow for rod holders, coolers and other gear.
Yoga: Another planing hull with an emphasis on stability, but generally in shorter lengths for ease of use/transport.
Expedition: A new category of displacement hull. A sturdy touring board with the extra hold-downs and lash points like a fishing board to allow for carrying gear.
What about Inflatables? Almost all of the above board types are available as inflatables (maybe not racing). These are SUPs made of materials similar to a Zodiac like Jacque Cousteau used to use. When not in use they fold (somewhat) small, to fit in your apartment or car trunk. Then when you want to use them you pump them up and are ready to go. The pumping up is simple, but can be bit of a workout. The resulting SUP is almost as good as a solid board in performance. Properly inflated they are rigid and solid feeling, and are definitely a viable alternative to traditional boards.