{"id":2354,"date":"2020-02-09T10:32:44","date_gmt":"2020-02-09T18:32:44","guid":{"rendered":"http:\/\/tradewindssailing.com\/wordpress\/?p=2354"},"modified":"2020-02-09T10:32:50","modified_gmt":"2020-02-09T18:32:50","slug":"nautical-terminator-tonnage-part-2","status":"publish","type":"post","link":"https:\/\/www.tradewindssailing.com\/wordpress\/nautical-terminator\/nautical-terminator-tonnage-part-2\/","title":{"rendered":"Nautical Terminator – Tonnage (Part 2)"},"content":{"rendered":"\n
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            Last time we distinguished three sorts of tonnage\napplicable to boats: displacement, deadweight tonnage, and gross and net\nregister tonnage. The displacement of your sailboat will be given in the\nowner\u2019s manual. The deadweight tonnage is not normally a big issue, as we do\nnot use our boats as cargo vessels. Cruisers, of course, must consider how much\nweight to carry before it will adversely affect the sailing characteristics of\ntheir yacht.<\/p>\n\n\n\n

            The third measurement, gross register tons or GRT, is a\nmeasurement of volume, not weight. On cargo ships this measurement is done\nprofessionally as it relates to tax revenue. But on recreational boats, you\u2019re\non your own. Emails to Catalina Yachts on this issue were not answered, and at Beneteau\nI was informed that the manufacturer does not provide the register tonnage of\ntheir boats. The only reason this would matter to you is if you desired to\ndocument your boat with the Coast Guard instead of getting a CF number from the\nstate of California. The federal documentation includes boxes for gross and net\nregister tons, but the state registration does not require it.<\/p>\n\n\n\n

            To calculate these values, we may rely on the simplified\nmeasurement form provided by the Coast Guard at https:\/\/www.dco.uscg.mil\/Portals\/9\/DCO%20Documents\/Marine%20Safety%20Center\/Tonnage\/Tonnage%20Guide%201%20-%20Simplified%20Measurement.pdf?ver=2017-06-09-123757-680<\/a><\/p>\n\n\n\n

            Basically, you calculate length x beam x depth, multiply\nby two factors they give you to account for hull shape and keel type, and\ndivide by 100. Depth<\/em> is not to be confused with draft<\/em>. Depth<\/em>\nis the vertical measurement from the deck (where it meets the hull, not\ncounting the height of the cabin trunk) to the bilge. The result is a pretty\nrough measurement of volume, but precise enough to satisfy Coast Guard\nregulations. <\/p>\n\n\n\n

            Using the formula, I measured Tradewinds\u2019 Megalina and Lionheart,\ntwo boats that are nominally the same size at 31 feet. Megalina (displacement\n8933 lbs.) comes out to 6.5 GRT, while Lionheart (displacement 9170 lbs.) is\n6.1 GRT. Since a register ton is 100 cubic feet, this means Megalina\u2019s internal\nvolume is 650 cubic feet, Lionheart\u2019s 610. (Actually, Megalina\u2019s design with the beam\ncarried aft and an after cabin, yields a lot more usable interior volume but\nthis is not represented in the given procedure.) Next, to obtain net register\ntons or NRT, we multiply the GRT by .9, yielding 5.85 for Megalina and 5.49 for\nLionheart. Voila! We are now admeasurers!<\/p>\n","protected":false},"excerpt":{"rendered":"

            Last time we distinguished three sorts of tonnage applicable to boats: displacement, deadweight tonnage, and gross and net register tonnage. The displacement of your sailboat will be given in the owner\u2019s manual. The deadweight tonnage is not normally a … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":13,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[31],"tags":[],"class_list":["post-2354","post","type-post","status-publish","format-standard","hentry","category-nautical-terminator"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/posts\/2354","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/comments?post=2354"}],"version-history":[{"count":4,"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/posts\/2354\/revisions"}],"predecessor-version":[{"id":2438,"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/posts\/2354\/revisions\/2438"}],"wp:attachment":[{"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/media?parent=2354"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/categories?post=2354"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/tags?post=2354"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}