The ornamental design for a boat or campingtrailer, as shown and described.
FIG. 1 is a rear and side perspective view of a boat or camping trailer
showing my new design;
FIG. 2 is a right side elevation view thereof, it being understood that the
broken lines are for illustrative purposes only and form no part of the
claimed design;
FIG. 3 is a top plan view thereof;
FIG. 4 is a left side elevation view thereof; and,