Marine Glossary

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Universal Plotting Sheets

Blank charts of the ocean with latitude lines spaced 3 inches apart and no longitude lines shown. They are used to set up a Mercator chart for a small region, which has numerous applications in many areas of marine navigation and weather.

They are available from several commercial outlets. They were at one time a US government pub, but no longer are. There are numerous pdf options available online to print a version on standard page sizes. (Starpath online resources has a couple versions.)

The longitude lines must be drawn in by the navigator using a universal scale provided on each sheet. This way the proper grid can be set up to match any latitude. Near the equator, 1° grids are nearly square; at higher latitudes they are rectangular. They come in pads of 50 sheets, printed both sides, that cost about $6. The implied scale is 3 inches equals 60 miles, but any scale can be used by re-labeling the latitude lines and adjusting the longitude diagram accordingly.

For more precise plotting, it is usually necessary to expand the scale to 3 inches equals 6 miles.

Your DR track can also be plotted on these same sheets, making it your primary chart for the open ocean part of the voyage. They are also useful for weather plotting and tactics.

For completeness, note that there are government issues of actual plotting sheets with preprinted latitudes and meridians, but these are not at all practical nor are they needed for any small craft navigation practice. See plotting sheets NGA version.

Abbreviation: UPS