{"id":47902,"date":"2026-01-15T22:21:51","date_gmt":"2026-01-15T22:21:51","guid":{"rendered":"https:\/\/maritimehub.co.uk\/?p=47902"},"modified":"2026-01-15T22:25:17","modified_gmt":"2026-01-15T22:25:17","slug":"colregs-lights","status":"publish","type":"post","link":"https:\/\/maritimehub.co.uk\/colregs-lights\/","title":{"rendered":"COLREGs \u2013 Lights"},"content":{"rendered":"\n<p><br><em>What vessels are telling you at night \u2014 and how misreading lights causes collisions<\/em><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Contents<\/h2>\n\n\n\n<p>Use the links below to jump to any section:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Why Navigation Lights Exist<\/li>\n\n\n\n<li>When Lights Must Be Displayed<\/li>\n\n\n\n<li>The Core Light Groups You Must Recognise Instantly<\/li>\n\n\n\n<li>Power-Driven Vessels Underway<\/li>\n\n\n\n<li>Power-Driven Vessels with Special Conditions<\/li>\n\n\n\n<li>Towing and Pushing Operations<\/li>\n\n\n\n<li>Fishing Vessels<\/li>\n\n\n\n<li>Vessels Restricted in Their Ability to Manoeuvre<\/li>\n\n\n\n<li>Vessels Constrained by Their Draught<\/li>\n\n\n\n<li>Sailing Vessels<\/li>\n\n\n\n<li>Anchored and Aground Vessels<\/li>\n\n\n\n<li>Pilot Vessels<\/li>\n\n\n\n<li>Small Craft and Incomplete Light Configurations<\/li>\n\n\n\n<li>Common Misidentifications and Traps<\/li>\n\n\n\n<li>Using Lights Together with Radar, AIS, and Bearing<\/li>\n\n\n\n<li>What to Do When the Lights Do Not Make Sense<\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">1. Why Navigation Lights Exist<\/h2>\n\n\n\n<p>Navigation lights exist to answer <strong>three operational questions<\/strong> at night:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>What type of vessel is this?<\/li>\n\n\n\n<li>What is it doing right now?<\/li>\n\n\n\n<li>How constrained is its ability to manoeuvre?<\/li>\n<\/ol>\n\n\n\n<p>They are not decorative, and they are not optional.<\/p>\n\n\n\n<p>At night, <strong>lights are primary information<\/strong>, not confirmation of what radar already told you.<\/p>\n\n\n\n<p>Many collisions occur because officers \u201cwaited for radar certainty\u201d while the lights already showed the truth.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">2. When Lights Must Be Displayed<\/h2>\n\n\n\n<p>Navigation lights must be shown:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>from sunset to sunrise<\/li>\n\n\n\n<li>during daylight in restricted visibility<\/li>\n\n\n\n<li>whenever deemed necessary to avoid collision<\/li>\n<\/ul>\n\n\n\n<p>If a vessel is underway at night and not displaying proper lights, that is <strong>not your protection<\/strong> \u2014 it is your warning.<\/p>\n\n\n\n<p>Rule 2 still applies.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">3. The Core Light Groups You Must Recognise Instantly<\/h2>\n\n\n\n<p>Every watchkeeper must instantly recognise:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>sidelights (red \/ green)<\/li>\n\n\n\n<li>masthead lights<\/li>\n\n\n\n<li>sternlight<\/li>\n\n\n\n<li>all-round white lights<\/li>\n\n\n\n<li>all-round red and green lights<\/li>\n<\/ul>\n\n\n\n<p>If you have to \u201ccount lights\u201d slowly, you are already behind.<\/p>\n\n\n\n<p>Recognition must be <strong>pattern-based<\/strong>, not analytical.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">4. Power-Driven Vessels Underway<\/h2>\n\n\n\n<p>A power-driven vessel underway normally displays:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>one or two white masthead lights (depending on length)<\/li>\n\n\n\n<li>red and green sidelights<\/li>\n\n\n\n<li>a white sternlight<\/li>\n<\/ul>\n\n\n\n<p>What this tells you operationally:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>the vessel has propulsion<\/li>\n\n\n\n<li>it is manoeuvrable<\/li>\n\n\n\n<li>COLREGs crossing, head-on, or overtaking rules apply<\/li>\n<\/ul>\n\n\n\n<p>The relative movement of sidelights tells you <strong>aspect<\/strong> long before radar vectors stabilise.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">5. Power-Driven Vessels with Special Conditions<\/h2>\n\n\n\n<p>Certain conditions modify the standard power-driven light pattern.<\/p>\n\n\n\n<p>These are <strong>warnings<\/strong>, not trivia.<\/p>\n\n\n\n<p>Examples include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>vessels engaged in towing<\/li>\n\n\n\n<li>vessels with length-dependent masthead configurations<\/li>\n\n\n\n<li>vessels not under command<\/li>\n<\/ul>\n\n\n\n<p>Each additional or altered light means <strong>reduced manoeuvring freedom<\/strong> or <strong>abnormal operation<\/strong>.<\/p>\n\n\n\n<p>If you treat these as \u201cstill just a power-driven vessel,\u201d you are ignoring critical information.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">6. Towing and Pushing Operations<\/h2>\n\n\n\n<p>Towing vessels display additional masthead lights indicating tow length.<\/p>\n\n\n\n<p>Operational reality:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>long tows cannot manoeuvre quickly<\/li>\n\n\n\n<li>course alterations may be limited<\/li>\n\n\n\n<li>the tow itself may be invisible on radar<\/li>\n<\/ul>\n\n\n\n<p>Never pass close to a towing vessel simply because the tug appears small.<\/p>\n\n\n\n<p>The lights are warning you about <strong>what you cannot see<\/strong>.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">7. Fishing Vessels<\/h2>\n\n\n\n<p>Fishing vessels display all-round red and white lights indicating fishing operations.<\/p>\n\n\n\n<p>Key mistake:<\/p>\n\n\n\n<p>Assuming all fishing vessels are the same.<\/p>\n\n\n\n<p>Fishing lights indicate:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>gear may extend far from the hull<\/li>\n\n\n\n<li>manoeuvrability may be severely limited<\/li>\n\n\n\n<li>course changes may not be possible<\/li>\n<\/ul>\n\n\n\n<p>If you treat a fishing vessel like a normal power-driven vessel, you are likely to pass too close.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">8. Vessels Restricted in Their Ability to Manoeuvre<\/h2>\n\n\n\n<p>These vessels display <strong>red-white-red<\/strong> all-round lights.<\/p>\n\n\n\n<p>This is one of the most important light patterns at sea.<\/p>\n\n\n\n<p>It means:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>the vessel cannot comply with COLREGs normally<\/li>\n\n\n\n<li>your manoeuvring options are greater than theirs<\/li>\n\n\n\n<li>you must keep well clear<\/li>\n<\/ul>\n\n\n\n<p>Examples include dredging, cable-laying, underwater operations, or vessels recovering gear.<\/p>\n\n\n\n<p>Failure to respect RAM lights is a frequent cause of collision and contact incidents.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">9. Vessels Constrained by Their Draught<\/h2>\n\n\n\n<p>A vessel constrained by draught may display three all-round red lights in a vertical line.<\/p>\n\n\n\n<p>This is not a \u201cstatus symbol.\u201d<\/p>\n\n\n\n<p>It is a statement:<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u201cI cannot safely deviate from my course.\u201d<\/p>\n<\/blockquote>\n\n\n\n<p>In narrow channels or traffic lanes, this light combination should immediately trigger <strong>early and decisive avoidance<\/strong>, not debate.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">10. Sailing Vessels<\/h2>\n\n\n\n<p>Sailing vessels display:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>red and green sidelights<\/li>\n\n\n\n<li>a sternlight<\/li>\n\n\n\n<li>optional all-round red over green<\/li>\n<\/ul>\n\n\n\n<p>Operational trap:<\/p>\n\n\n\n<p>Assuming sailing vessels always behave predictably.<\/p>\n\n\n\n<p>In practice:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>many sailboats have engines running<\/li>\n\n\n\n<li>lights may be misconfigured<\/li>\n\n\n\n<li>small craft may be poorly visible<\/li>\n<\/ul>\n\n\n\n<p>Do not assume competence because a vessel is under sail.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">11. Anchored and Aground Vessels<\/h2>\n\n\n\n<p>Anchored vessels show all-round white lights.<\/p>\n\n\n\n<p>Aground vessels show:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>anchor lights<\/li>\n\n\n\n<li>plus two all-round red lights<\/li>\n<\/ul>\n\n\n\n<p>Operational importance:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>anchored vessels may swing<\/li>\n\n\n\n<li>radar vectors may mislead<\/li>\n\n\n\n<li>background shore lights may mask them<\/li>\n<\/ul>\n\n\n\n<p>Anchored vessels are common collision victims at night because officers underestimate drift and swing.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">12. Pilot Vessels<\/h2>\n\n\n\n<p>Pilot vessels display white over red lights.<\/p>\n\n\n\n<p>These vessels operate in high-risk traffic environments and often make <strong>unexpected manoeuvres<\/strong>.<\/p>\n\n\n\n<p>They are not constrained, but they are <strong>busy<\/strong>.<\/p>\n\n\n\n<p>Treat pilot vessels with margin and anticipation.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">13. Small Craft and Incomplete Light Configurations<\/h2>\n\n\n\n<p>Small craft may display:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>reduced-range lights<\/li>\n\n\n\n<li>combined lanterns<\/li>\n\n\n\n<li>incorrect or incomplete configurations<\/li>\n<\/ul>\n\n\n\n<p>This does not absolve you of responsibility.<\/p>\n\n\n\n<p>Small craft are often:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>difficult to detect on radar<\/li>\n\n\n\n<li>poorly trained<\/li>\n\n\n\n<li>slow to react<\/li>\n<\/ul>\n\n\n\n<p>Professional ships must compensate for this reality.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">14. Common Misidentifications and Traps<\/h2>\n\n\n\n<p>Repeated night-time failure patterns include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>confusing fishing vessels with tugs<\/li>\n\n\n\n<li>missing RAM indicators<\/li>\n\n\n\n<li>assuming a single white light is a small craft when it is actually a tow<\/li>\n\n\n\n<li>mistaking shore lights for vessels<\/li>\n\n\n\n<li>trusting AIS labels over visual lights<\/li>\n<\/ul>\n\n\n\n<p>If lights and radar disagree, <strong>investigate immediately<\/strong>.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">15. Using Lights Together with Radar, AIS, and Bearing<\/h2>\n\n\n\n<p>Lights should never be used in isolation.<\/p>\n\n\n\n<p>A professional OOW cross-checks:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>visual lights<\/li>\n\n\n\n<li>radar bearing stability<\/li>\n\n\n\n<li>AIS data (with scepticism)<\/li>\n\n\n\n<li>charted traffic patterns<\/li>\n<\/ul>\n\n\n\n<p>Lights give <strong>identity<\/strong>.<br>Radar gives <strong>movement<\/strong>.<br>Together they give <strong>intent<\/strong>.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">16. What to Do When the Lights Do Not Make Sense<\/h2>\n\n\n\n<p>When lights appear contradictory or illogical:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>assume the other vessel may be wrong<\/li>\n\n\n\n<li>assume manoeuvrability may be limited<\/li>\n\n\n\n<li>increase CPA early<\/li>\n\n\n\n<li>reduce speed if necessary<\/li>\n\n\n\n<li>call the Master early in uncertainty<\/li>\n<\/ul>\n\n\n\n<p>Confusion is not a reason to delay action.<\/p>\n\n\n\n<p>It is a reason to <strong>create space<\/strong>.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Tags<\/h2>\n\n\n\n<p>COLREGs lights \u00b7 navigation lights \u00b7 night navigation \u00b7 collision avoidance \u00b7 bridge watchkeeping \u00b7 vessel identification<\/p>\n","protected":false},"excerpt":{"rendered":"<p>What vessels are telling you at night \u2014 and how misreading lights causes collisions Contents Use the links below to jump to any section: 1. Why Navigation Lights Exist Navigation lights exist to answer three operational questions at night: They are not decorative, and they are not optional. At night, lights are primary information, not [&hellip;]<\/p>\n","protected":false},"author":199,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"fifu_image_url":"","fifu_image_alt":"","c2c-post-author-ip":"","footnotes":""},"categories":[10,1,11,14,12],"tags":[8859],"class_list":["post-47902","post","type-post","status-publish","format-standard","hentry","category-bridge","category-latest","category-navigation","category-on-deck","category-watchkeeping","tag-8859"],"acf":[],"_links":{"self":[{"href":"https:\/\/maritimehub.co.uk\/?rest_route=\/wp\/v2\/posts\/47902","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/maritimehub.co.uk\/?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/maritimehub.co.uk\/?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/maritimehub.co.uk\/?rest_route=\/wp\/v2\/users\/199"}],"replies":[{"embeddable":true,"href":"https:\/\/maritimehub.co.uk\/?rest_route=%2Fwp%2Fv2%2Fcomments&post=47902"}],"version-history":[{"count":1,"href":"https:\/\/maritimehub.co.uk\/?rest_route=\/wp\/v2\/posts\/47902\/revisions"}],"predecessor-version":[{"id":47903,"href":"https:\/\/maritimehub.co.uk\/?rest_route=\/wp\/v2\/posts\/47902\/revisions\/47903"}],"wp:attachment":[{"href":"https:\/\/maritimehub.co.uk\/?rest_route=%2Fwp%2Fv2%2Fmedia&parent=47902"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/maritimehub.co.uk\/?rest_route=%2Fwp%2Fv2%2Fcategories&post=47902"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/maritimehub.co.uk\/?rest_route=%2Fwp%2Fv2%2Ftags&post=47902"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}