Now that I look closer, the sides on these might not just be covered but also zipped up at the bottom because you can see the cloth/canvas blowing out in the wind but it doesn’t appear to lift up. The only ones I have ridden were at Wisconsin Dells as a kid and those were open all the way around so we could look out.
http://www.dailymail.co.uk/ushome/index.html
update:Eleven dead, five missing and seven injured after duck-boat carrying 31 - including at least three children - CAPSIZES on stormy Missouri lake, as final video shows its battle to stay afloat