Nice report and sucks about the lower unit. I hit the West Arm for the first time this year and did a little exploring back towards Cross Lake, but didn't go quite that far. All new water for us as well and we took it easy, sticking to the main channel. I think Navionics has teh West Arm mapped now, so I'll be getting an update before next year. As you noted, they're not always reliable. Even during the deep freeze of winter, the ice can move the rocks around a bit.
Where were you staying if I can ask ?