This is an excerpt taken from the Hook 2 manual:
Trails
Trails are a graphical presentation of the historical path of the vessel,
allowing you to retrace where you have travelled.
From the factory, the system is set to automatically track and draw
the vessel’s movement on the panel. The system continues to
record the trail until the length reaches the maximum points, and
then automatically begins overwriting the oldest points.
The automatic tracking function can be turned off from the Edit
Trails dialog.
Creating new Trails
You can start a new trail from the Trails dialog. The dialog is
activated by selecting the trails tab in the dialog displayed when
you select the W/R/T option in the menu.
Editing waypoints, routes and trails
Waypoints, routes and trails are managed from their perspective
dialogs. You edit Waypoints, routes and trails similarly. For example,
to edit a trail:
1. Select W/R/T from the menu
2. Select the trails tab in the dialog
3. Select the trail you want to edit.
I have a Lowrance Elite unit and I edit my trails often. In my unit you just hit Menu – then select Waypoints, routes and trails – then hit enter – use the right arrow to move to Trails – then hit enter – then select the trail you want to edit – then hit enter – then select delete – then hit enter and the trail should be gone. To start a new trail – hit menu again and you should see a dialog box for new – then hit enter and a new trail should start.
Learning a unit can be confusing at times. Hope this helps.