What's a good iOS app for checking lake depths and making sure I'm not about to run aground when I'm out on the water?

Okay, so I've been messing around with Navionics Boating, and for a no-fuss approach to checking lake depths, it's not bad. I mean, I'm too tired to learn complicated apps, but this one's pretty straightforward. The lake contours are actually reliable, which is a big deal when you're trying to avoid underwater obstacles. It's especially useful if you're out on a lake you don't know that well. It's not perfect, and I've heard the battery life can drain fast, but for quickly checking depths, it works when you need it. Think of it like having a pocket reference guide, but for the water. Plus, it hasn't crashed on me yet, which is saying something these days.