My Hook 7 seems to have come with preloaded maps.  I can switch between Lowrance and Navionics and I don't really see any difference.  I assume they are a little dated, but they have come in quite handy.

 

Is there an advantage to getting a Navionics card?  Better maps?  More precise?

better maps. Lowrance base maps/preloaded maps are terrible relative to whats on map cards. 

Yeah, it's a little weird.  I've taken the boat out on Lake George and the St. Lawrence, and the maps don't show any contour lines.  And yet some relatively obscure power reservoirs near me have contour lines on the maps.

If you dont see a difference between pre loaded maps and navionics, you probably dont have sonar charts turned on. When I first got navionics it didnt look very good. Maybe a little better than the pre loaded, but not great. Somehow I stumbled on to the sonar chart and it makes a huge difference. Somewhere in the menu or options for navionics there will be a place to turn sonar charts on or off. Make sure that's on. It will be like night and day. I have been on both lake George and the st.lawrence, the navionics charts are very detailed. Especially the river. They are more like nautical charts than topo maps. I dont even know what some of the stuff is!

Jleebesaw,

I'll have a look.  I was just assuming there wasn't a Navionics card in it, and no matter what I was choosing (Navionics or Lowrance) it was defaulting to the pre-loaded maps.  I've looked and I'm pretty sure there isn't an SD card in the unit but I'll look again.