zoom problem on GP1670

Hope someone can help me here, as right now my new unit is completely useless...

I bought a GP1670 and use it with no map. I don't need a map, I just use waypoint to mark fishing spots.

Problem is the unit don't want to zoom enough. I am not sure exactly what zoom it allows, but it is WAY too broad for fishing my waypoints. I must see about 3 or 4 milles in the screen.

Is that because I am not using a map ?

How do I solve the problem ? is there a zoom-lock setting (to prevent zooming over a certain preset detail for each map - or in my case when there is no map) that i can turn off and if yes, how do i do that ?

Any other solution ?

Thanks !

If you do a search on this forum, for this topic, it has been answered many times. You must change your chart lock user setting. Once changed you can zoom in very very close.