Pat is right about Lake Powell. Get the map with the channel markers on it. And stay in the middle of the channel. Do not short cut even if it "looks deep". A good map and a good depth finder are essential for Powell. The bottom is different every day as the lake level changes daily. We have been there with a one foot change over night. A couple of years ago I ran up on a rock spire on the inside of a corner in a side channel, in a 17 foot bass boat at trolling speed. The stern was in 60 feet of water, the bow was gently beached on a rock shelf. I reversed slowly and we were off and good to go. Stay in the center of the channel. Watch for color changes in the water. Go slow if in question. It is a beautiful if not magical place. Charts are a good supplement to a map and a depth finder, but don't rely on charts like we do in the PNW! There are rocks that are high and dry sometimes and one foot below the water line as the level changes. Have a great trip to Powell! It is beautiful. I have spent some time exploring there and never had a problem. Slow is good unless in the main channel and following the markers, then you can make good time with some certainty. The center of most side channels is fine. The edges can yield surprises. As you look at those rock spires think of what they might look like if just under the water surface! Enjoy Powell, it is a treasure.