Is shallow water slower than deep water? A Forum Discussion

This is just one of the many discussions on the Paddle Monster Forum available to All Access and Basic Members, moderated by our coaches, Larry Cain, Seychelle and Travis Grant.

The Question:
So I’ve been noticing something interesting on my speed coach, when I paddle in water 3′ or less deep, I see a big drop in my speed numbers. I noticed this especially in a couple inland places I train and kept wondering when I round this turn why on earth does it feel harder and I go slower? Waters kinda murky but I discovered the water there is much shallower, 2.5-3′ deep. I have since noticed this in a few other places with shallower water, once you get out in the deep stuff again it’s fast. I had been thinking for a long time it was just in my head but there is definitely a fundamental difference. Has anyone else noticed this or know why? This could really impact racing strategy for certain inland lakes and rivers I’d think. Thoughts?

Member Response:
Yes it has a massive effect. I train on a canal in the UK which is 4ft deep at the most and its only when I go out on deeper water in Races that I feel the greater release of the board and ease of travel as a result of applying the power to to my paddle stroke.
Larry highlighted this some time ago. I would say also its when paddle in deeper water I find I can sprint more effectively as seemingly the reduced drag allows me to get the board planing easier.
On lakes, the course is the course regardless of the depth, but on rivers get in the channel when heading down stream. Heading up stream cutting the corners and going where it is shallower- whilst subject to drag effects- is less impacted by the flow of the river which is less actively usually at the shorelines.

The Answer from Larry Cain (there are many other comments on this thread on the app):
Shallow water is slower water. No question about it. It has to do with drag on the board from the wave the comes off the board and moves downward through the water column (like your side wake but directed downward). When the water is deeper that wave basically dissipates before it interacts with the bottom so there is no noticeable drag. However in shallower water about 4 feet or less you feel it. And when the water is only a couple of feet deep it is incredibly noticeable.

The feeling is not unlike what Gareth described above and it feels like your board is being sucked down and that you’re dragging something. It is almost impossible to get the feeling of the board being up and skipping across the surface of the water.

It helps to know the water depth where you are paddling, particularly in races. That is part of the local knowledge that can always be advantageous. It also helps to use your GPS and have it visible so you can get instant feedback. When it gets really shallow and heavy you can feel it, but you’d be surprised that sometimes you can’t feel it so much but you’re still going a little slower.

Rivers are challenging as is tidal water because you have to factor current into the equation in addition to water depth. If you’re going down current it makes a lot of sense to stay in the middle of the channel. It is probably deeper there and there is always more current in the middle than near shore. However if you’re going against the current or tide it is more problematic. You want to get out of the current and closer to shore, but getting too close it gets too shallow and slower. The only way you can negotiate this effectively is, again, using a GPS. It can tell you your instantaneous speed and help you decide on the best line. Sometimes it is better to be in deeper water and more current. Other times it is better to be in shallow water and less current. It really depends on the strength of the current.

In lakes or bigger bodies of water that may have shoals or sandbars is it more a question of whether is it better to go a greater distance in deeper water or a shorter distance through shallower water. Here’s where local knowledge of the dimensions of the sandbar becomes really helpful.

The last thing to remember is that not only does the shallow water slow you down, it also tires you out. There’s not much better way to just suck energy out of your muscles than paddle a great distance in shallow water. Definitely trying to minimize the amount of very shallow water paddling in a race is important.

Larry

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Look for this in the General Section in All Topics. It’s called¬†Shallow water slower than deep water?

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