{"id":10624,"date":"2014-10-15T08:12:51","date_gmt":"2014-10-15T12:12:51","guid":{"rendered":"http:\/\/noaacoastsurvey.wordpress.com\/?p=10624"},"modified":"2014-10-15T08:12:51","modified_gmt":"2014-10-15T12:12:51","slug":"survey-helps-ensure-safe-parking-for-deep-draft-vessel-in-sf","status":"publish","type":"post","link":"https:\/\/nauticalcharts.noaa.gov\/updates\/survey-helps-ensure-safe-parking-for-deep-draft-vessel-in-sf\/","title":{"rendered":"Survey helps ensure safe \u201cparking\u201d for deep-draft vessel in SF"},"content":{"rendered":"

In preparation for the M\/V TERN\u2019s anticipated arrival this week in San Francisco Bay, the Coast Guard and Port of San Francisco asked Coast Survey for a bathymetric survey of the proposed anchorage site. TERN<\/a> is a semi-submersible vessel with a 60-foot draft, and the proposed anchorage site has charted depths of 62 feet and 63 feet \u2012 leaving no room for error, to say the least. The question was\u00a0whether there are\u00a0any spots\u00a0shoaler than 62 feet.
\nThis isn\u2019t your everyday anchorage.
\n
\n\u201cThis vessel floods ballast tanks and partially sinks, putting the main deck below water. Items can then be floated onto the ship, and then water is pumped out of the ballast tanks to bring the main deck back above water level,\u201d explains Lt. Michael Davidson, chief of Coast Survey\u2019s Navigation Response Branch. \u201cTERN won’t actually be anchoring in the anchorage, but rather will be held in place with tugs while cranes are transferred. When she submerges during the operation, her\u00a0submerged depth is 60 feet.\u201d
\nCoast Survey assigned Navigation Response Team 6<\/a> to investigate the depths with its multibeam echo sounder, to ensure that the TERN will have the under keel clearance she needs. Last week, as requested by the Coast Guard, NRT 6 conducted an investigative survey around Whiskey 2, Anchorage 9. (Whiskey 2, depicted on the survey chart as W2, is a \u201cbucket\u201d that resides within Anchorage 9. A bucket is where they usually park a ship.) Of the many small, pocked features, the team found six that exhibit a height above bottom. Most notable of these features is a 60\u2019 shoalest sounding near a 63\u2019 charted depth \u2013 near the location where TERN was\u00a0supposed to submerge.<\/p>\n

[wpvideo HbAGMB3P]<\/p>\n

After the Coast Guard received the team\u2019s report of obstructions, they asked Coast Survey to investigate an additional area. They were looking for a spot that was at least 62′ deep, free of any features.
\n\u201cIn our area of survey near W1, there were no features that exhibited a height above bottom or showed any significant scour,\u201d reports Ian Colvert, acting team lead of Coast Survey\u2019s Navigation Response Team 6. \u201cThe area near W1 is a much more promising place to park the TERN, versus W2 which had a few features and depths not as deep.\u201d
\nCoast Survey has a proud 200-year history of protecting\u00a0ships from accidents. NRT6 gives us a very real example of how that mission\u00a0continues today.
\n\"reduced<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

A semi-submersible vessel needed an anchorage in San Francisco Bay. After the Coast Guard received the navigation response team\u2019s report of obstructions, they asked Coast Survey to investigate an additional area. They were looking for a spot that was at least 62′ deep, free of any features.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0,"footnotes":""},"categories":[37,11],"tags":[109,244],"class_list":["post-10624","post","type-post","status-publish","format-standard","hentry","category-commerce","category-navigation-response-teams","tag-alaska","tag-san-francisco-bay"],"_links":{"self":[{"href":"https:\/\/nauticalcharts.noaa.gov\/updates\/wp-json\/wp\/v2\/posts\/10624","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nauticalcharts.noaa.gov\/updates\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nauticalcharts.noaa.gov\/updates\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nauticalcharts.noaa.gov\/updates\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/nauticalcharts.noaa.gov\/updates\/wp-json\/wp\/v2\/comments?post=10624"}],"version-history":[{"count":0,"href":"https:\/\/nauticalcharts.noaa.gov\/updates\/wp-json\/wp\/v2\/posts\/10624\/revisions"}],"wp:attachment":[{"href":"https:\/\/nauticalcharts.noaa.gov\/updates\/wp-json\/wp\/v2\/media?parent=10624"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nauticalcharts.noaa.gov\/updates\/wp-json\/wp\/v2\/categories?post=10624"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nauticalcharts.noaa.gov\/updates\/wp-json\/wp\/v2\/tags?post=10624"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}