jaxxman,
It all depends on what you want to do with your 898 unit and where you want to mount it. If you are going to run it on the bow you will need some way of mounting the transducer to the trolling motor. You can call the Humminbird Customer resource folks and arranges to swap out the standard transom transducer for the trolling motor mounted one (same transducer just different mounting hardware) or look at using some hardware from another company (Transducer Shield & Saver or Transducer Armor). Other than the memory card you should have all you need unless you are planning on InterLinking it to another Humminbird or using its video output or something like that.


JTMavs,
Let us know what brand those 4GB SDHC cards are and if they work in your Humminbird or not (not all brands will).