I am amazed how many times I see something like this posted on a kayaking forum or Reddit:
"I need advice on a first kayak, I have $400 to spend on boat, paddle and PFD. I will be mostly on lakes and the occasional slow moving river. What do you suggest?"
"What do you guys think of this $250 kayak at (insert name here) sporting goods, it's a great deal and I really want to start kayaking"
In the past I have taken heat for deriding the recreational kayakers in the world, and I mean no disrespect to them. I feel that they are literally paying the bills - as they are the fastest growing segment of kayaking - for the touring kayaks that far fewer people paddle. But I thought I would point out a few of the basics to new paddlers who are thinking about their first boat. I have to stress this is my opinion, and I am sure others would have other comments to place here, and I welcome that.
My first questions for new paddlers are these: Where are you going to paddle, and what do you see your self doing in a kayak in two years? If you are going to be paddling on slow moving rivers then I would recommend a different kayak than if you are going to primarily be on lakes or other flat water. If your goal is to eventually camp out of a kayak or do simple touring with the occasional overnight That would steer me towards different Kayaks as well.
Then lets talk about the shape of your prospective kayak and how that effects how it will perform. Short Kayaks are also generally pretty wide. Long kayaks are generally more narrow. Short Kayaks turn well, but don't like going in a straight line. Long Kayaks go in a straight line pretty well - which is called tracking, a long kayak 'tracks' well - but they don't really like turning as much. Narrow kayaks are 'tippy' while wide kayaks are more stable. (If you think this is where I should be talking about primary and secondary stability, stop. The person buying their first kayak doesn't have the knowledge level - yet! - for that conversation.)
So if you answered the first question by saying I will use this kayak mostly on slow moving rivers, I would point you towards a shorter kayak, as it will turn quicker and be more stable which suits a river. And for clarity, when I say short, I am suggesting Below 12 feet in length, maybe even as short as 10 feet long. If you said maybe the occasional river, but really I want to use it mostly on a lake, then I would suggest a kayak 12 feet or longer. I think 10 and 12 foot long kayaks are a nice sweet spot in the middle for the first time kayak buyer, as they turn fairly well, and track decently. They are also pretty universally stable. If you are going to be on a river I would recommend a kayak with at least one bulkhead (or flotation) so if the kayak fills with water at least part of it will remain above the surface, making the boat much easier to deal with.
If at any point you think you want to kayak camp, or do day touring with the occasional overnight trip, I would start looking at kayaks in the 14 foot range. Boats at 14 feet can hold enough gear for shorter trips, and offer a glimpse of the performance found in longer touring kayaks.
I am not a fan of most kayaks below 10 feet in length. I don't think they are a fair representation of what kayaking is really like, But starting at around 10 feet you can get a really lovely recreational kayak. If you have $400 for Kayak, PFD and Paddle, my advice is to keep saving money. You are going to end up with something like this with a heavy paddle and an uncomfortable PFD. Saying you want to start kayaking and ending up with a kayak like that - to me, and this is where I start getting in trouble! - is like saying you want a sports car and you buy a Toyota Yaris. I love my Yaris, but it's not a sports car.
My final piece of advice is to paddle. Paddle everything from little sit on top kayaks to long touring kayaks. Paddle kayaks you know you could never afford to buy. Go to paddle demo days, rent kayaks. Borrow Kayaks. Talk to people who own kayaks about what they paddle - trust me, we love talking about our kayaks! - and then maybe they will let you paddle their kayak. Most people that own one kayak, own more than one. Go kayaking with them. You have to get your bottom into a seat to see what kayaks feel like.
A very long time ago when I was shopping for my first kayak I lived in Lower Manhattan. My one flight up, tiny apartment in the West Village wouldn't accommodate a kayak. So I bought a paddle and PFD, and I rented kayaks on Long Island. I developed a relationship with a couple of places that rented kayaks and I paddled everything in their inventory. I knew I wanted to do kayak touring which limited my options somewhat, but I got experience paddling a lot of different kayaks. Over the course of a couple of years I developed the vocabulary to describe the different kayaks I paddled. Then when it was time for me to actually buy something I knew what I was looking for, and it didn't take me long to find it.