With UTM, you have different grids to choose among. there is NAD27, NAD 83, WGS 84 et al. I understand that the Coast Guard and other responders prefer to use Lat lon with a degree, minute, and decimal minute format - less ambiguity that way, since the same coordinate numbers plotted on the various UTM grids will give you different placements.

It is not hard to convert, but I leave my unit in lat lon, decimal minutes for those special occasions.....