Working With the 11th Edition Area Limits Charts
The 11th edition of the International Navigating Conditions Area Limits Map came out a few years back and it changed a few things that affect how you file your compliance documentation. I dealt with this directly when a ship inspector called me out on a boundary dispute between two ports that used to fall on opposite sides of a line. One port said "open sea rules apply," the other said "inland rules apply," and both had copies of the map that looked almost identical but weren't quite. The core document defines which COLREGs provisions apply where. If you are navigating under Annex I light specifications or filing paperwork about which rule set governs a particular stretch of water, you need to know which version of the map is current. The 11th edition revised several coastal boundaries, particularly around the South China Sea approaches and the western Mediterranean entries. If you are still using the 10th edition for anything formal, you are already behind.
Where to Get the International Navigating Conditions Area Limits Map 11th
The official document is published by the International Maritime Organization. You can download it directly from their website at imo.org, usually under the publications section labeled "Navigation and Communication." It is free. The PDF runs roughly 40 to 60 pages depending on whether it includes the full cartographic plates or just the summary charts. Some national hydrographic offices also host mirrored copies, but those can lag behind by months if the IMO updates a corrigendum. Always check the publication date on whatever file you pull. I stopped trusting third-party downloads after my first edition mix-up. There is a Turkish maritime supply site that hosted a version labeled "11th" but it was actually a 2017 pre-release with three boundary corrections missing. Took me six weeks to figure out why my vessel's route plan didn't match the inspector's copy.
How to Use It in Practice
Start by pulling up the chart plate that covers your area of interest. The map is divided into regional sheets, not one continuous globe view. Each sheet shows territorial sea baselines, straight baseline configurations, and the exact points where inland navigation rules transition into international rules. Look for the legend key first. The symbols shift slightly between editions, and a triangle that meant something different in the 10th edition now means something else in the 11th. The most common thing people get wrong is assuming the boundary line is a single smooth curve. It is not. In most cases it follows a series of enumerated geographical coordinates provided in the appendices. You need to cross-reference those coordinates against your electronic chart display. If you are plotting manually, use the coordinate tables in the back of the document, not the visual line on the map. The visual line is illustrative. The coordinate list is authoritative. Here is a specific edge case that bit me recently. We had a vessel transiting near the Strait of Juan de Fuca. The map shows the boundary between Canadian inland waters and international waters running through that strait. The visual representation on the map makes it look like the entire channel falls under one regime, but the coordinate list in Appendix B shows a series of turning points that actually place the southern portion under international COLREGs and the northern portion under Canadian inland rules. We filed our navigation equipment certification under the wrong set because someone on our end read the map image instead of the coordinate table. Took another trip to port to refile everything. Now I always verify with the coordinate tables before finalizing any paperwork.
Get the Full Details
Another thing worth noting: the 11th edition introduced revised baseline declarations for several countries. Denmark's Greenland coastline changed. Norway updated its Vågsøy to Fedje baseline sequence. If your route touches either of those areas, make sure your charts are updated to match. Old electronic chart systems don't always reflect these changes automatically, and some chart update subscription services miss them entirely because they rely on national hydrographic offices rather than the IMO directly. If you need to work with this document regularly, I recommend keeping a printed copy in your navigation folder alongside your electronic charts. Paper does not crash, does not lag on updates, and does not get replaced silently by a distributor who thought they were sending you a newer version. I keep the IMO-published PDF downloaded locally as a backup too, but the printed copy is what I reach for when I need to show someone exactly where a line runs. The main limitation of this map is that it only covers the surface boundary between regimes. It does not address submerged pipeline zones, submarine cable protection areas, or fishing conservation limits. Those are governed by separate conventions and national legislation. People sometimes conflate the two and assume that crossing from "inland" to "international" on this map also changes your obligations under UNCLOS Article 211 or the EU Port State Control directives. It does not. The map is narrow in scope and that is by design. Don't treat it as a comprehensive legal reference for anything beyond COLREGs applicability.
If you are doing this work occasionally rather than constantly, the biggest time sink is simply finding the right regional sheet. The document indexes them by region code rather than by name, which is annoying. Write down the regional code for your area of operation before you start digging through the PDF. Saves about twenty minutes per search.
