{"id":14350,"date":"2025-11-02T03:54:32","date_gmt":"2025-11-02T03:54:32","guid":{"rendered":"https:\/\/craighordlow.com\/?p=14350"},"modified":"2025-11-07T05:50:09","modified_gmt":"2025-11-07T05:50:09","slug":"orca-sailboat-attacks-motor-vs-no-motor","status":"publish","type":"post","link":"https:\/\/craighordlow.com\/index.php\/2025\/11\/02\/orca-sailboat-attacks-motor-vs-no-motor\/","title":{"rendered":"Iberian Orca Whale Boat Attacks: The Acoustic Intensity is a Function of Speed, Regardless of Motor."},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_81 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/craighordlow.com\/index.php\/2025\/11\/02\/orca-sailboat-attacks-motor-vs-no-motor\/#Tldr\" >Tl;dr<\/a><ul class='ez-toc-list-level-5' ><li class='ez-toc-heading-level-5'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/craighordlow.com\/index.php\/2025\/11\/02\/orca-sailboat-attacks-motor-vs-no-motor\/#_Acoustic_emission_intensity_of_an_unmotored_sailboat_will_equal_that_of_a_motored_boat_at_12_Knots_At_15_Knots_the_sailboat_will_be_2x_%E2%80%98louder_The_intensity_increases_exponentially_with_speed\" >\u00a0Acoustic emission intensity of an unmotored sailboat will equal that of a motored boat at ~12 Knots.\u00a0 At ~15 Knots, the sailboat will be ~2x &#8216;louder&#8217;.\u00a0 The intensity increases exponentially with speed<\/a><\/li><\/ul><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/craighordlow.com\/index.php\/2025\/11\/02\/orca-sailboat-attacks-motor-vs-no-motor\/#At_what_speed_does_an_unmotored_sailboat_become_louder_than_a_motored_boat_all_things_equal\" >At what speed does an unmotored sailboat become louder than a motored boat (all things equal)?<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/craighordlow.com\/index.php\/2025\/11\/02\/orca-sailboat-attacks-motor-vs-no-motor\/#15_Knots_is_2x_the_%E2%80%98noise_of_12_Knots_19_Knots_is_4x_the_%E2%80%98noise_of_12_Knots\" >15 Knots is ~2x the &#8216;noise&#8217; of 12 Knots. \n19 Knots is ~ 4x the &#8216;noise&#8217; of 12 Knots.<\/a><\/li><\/ul><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/craighordlow.com\/index.php\/2025\/11\/02\/orca-sailboat-attacks-motor-vs-no-motor\/#See_the_main_data_analysis_and_ideas%E2%80%A6\" >See the main data analysis and ideas&#8230;<\/a><\/li><\/ul><\/nav><\/div>\n<h4><span class=\"ez-toc-section\" id=\"Tldr\"><\/span>Tl;dr<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<h5><span class=\"ez-toc-section\" id=\"_Acoustic_emission_intensity_of_an_unmotored_sailboat_will_equal_that_of_a_motored_boat_at_12_Knots_At_15_Knots_the_sailboat_will_be_2x_%E2%80%98louder_The_intensity_increases_exponentially_with_speed\"><\/span>\u00a0Acoustic emission intensity of an unmotored sailboat will equal that of a motored boat at ~12 Knots.\u00a0 At ~15 Knots, the sailboat will be ~2x &#8216;louder&#8217;.\u00a0 The intensity increases exponentially with speed<span class=\"ez-toc-section-end\"><\/span><\/h5>\n<h3><span class=\"ez-toc-section\" id=\"At_what_speed_does_an_unmotored_sailboat_become_louder_than_a_motored_boat_all_things_equal\"><\/span>At what speed does an unmotored sailboat become louder than a motored boat (all things equal)?  <span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>We can roughly approximate the speed at which a sailboat traveling with no motor will emit structual borne noise (SBN) that is greater than or equal to the point where Hydrodynamic Turbulence Noise (HNT) from sailing equals Structural Borne Noise (SBN) from the engine.<\/p>\n<ul>\n<li>SBN Power (PSBN\u200b): Fixed, high intensity constant set by engine RPM. Dominates at low speeds.<\/li>\n<li>HNT Power (PHNT\u200b): Noise from water flow. Power increases exponentially with velocity (V).<\/li>\n<\/ul>\n<p><a href=\"https:\/\/craighordlow.com\/index.php\/2025\/10\/05\/cause-of-orca-boat-attacks-and-what-to-do-about-them\/?fbclid=IwY2xjawNzsd9leHRuA2FlbQIxMABicmlkETFvQzY2UERVd2FteGpSZnU1AR48ZCOZ3-nmuxd5Zq3QsSgaFhCBbCMAf86iDRJw4B-uetl92oINlHCAKBCfHw_aem_NxmcQxKEAPTuLt1JMpHlCg#%22Noisiest%22_Rudders_Attacked_the_Most_But_Data_Not_Normalized_for_Prevalence\" target=\"_blank\" rel=\"noopener\">Read my other Orca speculations<\/a><\/p>\n<h4><span class=\"ez-toc-section\" id=\"15_Knots_is_2x_the_%E2%80%98noise_of_12_Knots_19_Knots_is_4x_the_%E2%80%98noise_of_12_Knots\"><\/span>15 Knots is ~2x the &#8216;noise&#8217; of 12 Knots.<br \/>\n19 Knots is ~ 4x the &#8216;noise&#8217; of 12 Knots.<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<p>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"589\" height=\"356\" src=\"https:\/\/craighordlow.com\/wp-content\/uploads\/2025\/10\/Exponential-Sailboat-Sound.png\" alt=\"At ~12 knots, a sailboat&#039;s acoustic emissions are roughly equal to a motor (a crude estimate)\" srcset=\"https:\/\/craighordlow.com\/wp-content\/uploads\/2025\/10\/Exponential-Sailboat-Sound.png 589w, https:\/\/craighordlow.com\/wp-content\/uploads\/2025\/10\/Exponential-Sailboat-Sound-300x181.png 300w\" sizes=\"(max-width: 589px) 100vw, 589px\" title=\"| Craig Hordlow\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/p>\n<h2><span class=\"ez-toc-section\" id=\"See_the_main_data_analysis_and_ideas%E2%80%A6\"><\/span>See the main data analysis and ideas&#8230;<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><a href=\"https:\/\/craighordlow.com\/index.php\/2025\/10\/05\/cause-of-orca-boat-attacks-and-what-to-do-about-them\/\">on this page<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Sailboat speed needed to match the noise of a running motor is 10\u00a0to\u00a015\u00a0knots.<\/p>\n","protected":false},"author":1,"featured_media":14514,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"h5ap_radio_sources":[],"cybocfi_hide_featured_image":"","footnotes":""},"categories":[95,96],"tags":[82,83,97,98],"class_list":["post-14350","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-science","category-orcas","tag-orca-whales","tag-killer-whales","tag-orcas","tag-iberian-whales"],"featured_image_src":"https:\/\/craighordlow.com\/wp-content\/uploads\/2025\/11\/Speed-to-Sound.png","featured_image_src_square":"https:\/\/craighordlow.com\/wp-content\/uploads\/2025\/11\/Speed-to-Sound.png","author_info":{"display_name":false,"author_link":"https:\/\/craighordlow.com\/author\/craig\/"},"_links":{"self":[{"href":"https:\/\/craighordlow.com\/index.php\/wp-json\/wp\/v2\/posts\/14350","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/craighordlow.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/craighordlow.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/craighordlow.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/craighordlow.com\/index.php\/wp-json\/wp\/v2\/comments?post=14350"}],"version-history":[{"count":16,"href":"https:\/\/craighordlow.com\/index.php\/wp-json\/wp\/v2\/posts\/14350\/revisions"}],"predecessor-version":[{"id":14561,"href":"https:\/\/craighordlow.com\/index.php\/wp-json\/wp\/v2\/posts\/14350\/revisions\/14561"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/craighordlow.com\/index.php\/wp-json\/wp\/v2\/media\/14514"}],"wp:attachment":[{"href":"https:\/\/craighordlow.com\/index.php\/wp-json\/wp\/v2\/media?parent=14350"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/craighordlow.com\/index.php\/wp-json\/wp\/v2\/categories?post=14350"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/craighordlow.com\/index.php\/wp-json\/wp\/v2\/tags?post=14350"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}