Dead reckoning is navigation without the aid of landmarks. When paddling in fog, it is critical to determine correctly your speed and time over the distance you want to travel. In shallow depths, paddlers will have to work much harder to maintain the same speed than in deeper seas. I don't however recommend paddlers take chances in the fog if it is not necessary, and if you are just developing these essential skills. We generally paddle 20 minute miles at 3 knots and 30 minute miles at 2 knots.
Speeds can obviously vary when dealing with shallow water, significant headwinds, or tidal streams.
Wendell Phillips runs his kayak company out of Peachland. He works on BC interior and coastal waters in the summer and instructs and guides for Ocean Trek Kayaking on the South China Sea in the winter months.