CM93 charts usually come as a compressed archive (ZIP or RAR).
CM93 or containing subfolders numbered by region).Downloading and installing CM93 v2 charts is a rite of passage for the modern cruiser. It provides a free, globally consistent vector chart base that still beats many commercial offerings for offshore passage planning.
Recap of the process:
Remember the golden rule of electronic navigation: Two sources are one; one source is none. Use CM93 v2 alongside a free mobile app (like Navionics boating trial) or a satellite overlay. That way, when the old chart is wrong, you have a second opinion.
Now go download, install, and sail with confidence—but keep one hand on the paper chart.
Have a specific error not covered? Visit the official OpenCPN forums or the CruisersForum "Navigation" section. Do not ask for pirated links—ask for help with chart paths and encryption.
CM93 v2 Charts: Complete Download and Installation Guide CM93 v2 charts are a standard for world vector charts used extensively by the yachting community in OpenCPN and other marine navigation software. While these charts are technically legacy data—originally developed by C-Map—they remain a popular resource for planning and secondary navigation. Understanding CM93 v2 Charts cm93 v2 charts download install
CM93 version 2 charts use a unique data structure unlike standard S-57 ENC charts. A complete global dataset typically includes 144 subdirectories, each covering a geographic area.
Version Identification: A valid CM93 v2 directory contains an empty file with a .EXD extension (e.g., 20110803.EXD), which indicates the edition's release date.
Scale Levels: The data is organized into scale levels from 'Z' (world overview) down to 'G' (detailed harbor plans).
Compatibility: OpenCPN and qtVlm are the most common platforms that support this format. Note that CM93 v3 is a different, encrypted format and is not compatible with OpenCPN. Where to Download CM93 v2 Charts
Because CM93 v2 is no longer commercially updated, these charts are often distributed through community-maintained links and maritime forums. Installing Charts - OpenCPN
CM93 v2 is a global vector chart format originally developed by C-MAP. While officially considered obsolete since approximately 2014, these charts remain popular among the cruising community because they are unencrypted and compatible with open-source navigation software like OpenCPN. Critical Warning CM93 charts usually come as a compressed archive
CM93 v2 charts found online are often outdated (most "recent" legitimate data dates to 2011–2012) and are frequently distributed via unofficial or pirated channels. Never rely solely on these charts for primary navigation. For safe passage-making, always use updated official ENCs or licensed charts from providers like o-charts. 1. Downloading CM93 v2 Charts
Because CM93 v2 is no longer sold to the public, users typically source them from maritime community forums or file-sharing sites.
Identify the Correct Version: Ensure you are getting Version 2. Version 3 is encrypted and will not work with OpenCPN.
Verify the File Structure: A legitimate CM93 v2 folder should contain approximately 144 subdirectories (named with 8-digit numbers like 00300000) and a .EXD file (e.g., 20110803.EXD) in the top directory.
Sources: Community platforms like Cruisers & Sailing Forums or sites like Maritime Forum (SeaTracker) often host legacy download links. 2. Installing in OpenCPN
Once downloaded and extracted, follow these steps to add the charts to your navigation system: CM93v2 chart download - Cruisers & Sailing Forums Ensure the folder contains the necessary database files
CM93v2 chart download - Cruisers & Sailing Forums. Forums. New Posts. Home > Seamanship, Navigation & Boat Handling > OpenCPN. Cruisers Forum Installing Charts - OpenCPN
| Problem | Likely Cause | Solution |
|---------|--------------|----------|
| “No CM93 charts found” | Wrong folder name | Re-add directory, ensure CM93EDITION.DAT exists |
| All charts show as tiny outlines | Missing detail cells | Your copy is partial – find full 2.5GB set |
| Chart edges have vertical lines | Outdated cell boundary file | Delete CM93DICT.DAT and rebuild database |
| OpenCPN crashes on zoom | Corrupted cell in folder 04800000 | Temporarily move that folder out, then rebuild |
Let’s assume you have a legitimate copy (e.g., you ripped it from an old C-MAP cartridge you owned). Here’s how to make it work in OpenCPN 5.10+:
Sometimes the directory double-nesting confuses OpenCPN:
Move the contents up one level.