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This is a tracking category. It is used to build and maintain lists of pages—primarily for the sake of the lists themselves and their use in article and category maintenance. It is not part of the encyclopedia's categorization scheme. More information: This category is hidden on its member pages—unless the corresponding user preference (Appearance → Show hidden categories) is set. These categories are used to track, build and organize lists of pages needing "attention en masse" (for example, pages using deprecated syntax), or that may need to be edited at someone's earliest convenience. These categories also serve to aggregate members of several lists or sub-categories into a larger, more efficient list (discriminated by classifications). Typically, tracking categories are automatically populated by templates invoked in pages or by the MediaWiki software (see Special:TrackingCategories for an overview of the latter).

Administrators: Please do not delete this category as empty! This category may be empty occasionally or even most of the time.

Populated by {{ Ship}} and individual ship-prefix templates like {{ HMS}} when errors in a template's parameters are detected. These templates take the forms:

{{ship|<prefix>|<name>|<disambiguator>|<format control>}}

{{HMS|<name>|<disambiguator>|<format control>}}

When errors are detected, the templates emit error messages in the forms:

Error: {{ Ship}} <message> (help)

Error: {{ HMS}} <message> (help)

where the help link links to this page.

The messages are:

missing prefix – {{ship}} only – this message is emitted when the |<prefix> positional parameter is present but empty AND |<format control> positional parameter is set to 5 or 6 OR when |up=yes

missing name – these templates require the ship's name in the |<name> positional parameter

missing disambiguator – when the |<format control> positional parameter is 1, 3, or 5 the template requires a value in |<disambiguator>

invalid control parameter: <detail> – this message emitted when the |<format control> positional parameter holds a value that is not 1, 2, 3, 5, or 6; the invalid control parameter is specified in the error message

See also: Category:Pages using Ship with unknown parameters