>>1561020Rental kayaks are often made from Polyethylene or the like. They're very rugged and easy to repair but heavy as fuck and (normally) pretty short and fat which means relatively low hull speed and high resistance in the water.
While getting into the sport this is the kind of kayak I would recommend simply because you can drag it over rocks without doing major damage to it, they're wide so they're stable and very forgiving and you can pack a lot of shit into it without it markedly affecting performance.
Once you figure out if you like kayaking and get some experience on the water, look for a fiberglass kayak. They're lighter and stiffer than the PE ones and usually longer and slimmer, meaning they go faster with less effort. The slimmer hull also means less stability though, so you will need to either have good balance/reactions or have some experience kayaking to get the most out of it. Please note, this is something that can make or break the sport for you. I've had friends who wanted to try "the fast ones" the first time they went out and they took about 20 minutes and 3-5 flips before even getting seated in them. Needless to say they didn't have a good time.
My last kayak was laid up with a kevlar hull and a carbon deck. It was very light, very slim and very fast but it was definitely unstable and since the material in the hull was so thin (for lightness), basically anything more than brushing a rock meant big problems. There's a nice balance between what I had and a PE kayak which is the sweet spot to look for.