<story><title>Titanic tourist submersible goes missing with search under way</title><url>https://www.bbc.com/news/world-us-canada-65953872</url></story><parent_chain><item><author>minedwiz</author><text>Communicating with submarines is actually a nightmare. The saltwater ruins most radio communications, so you have no chance to receive GPS signals, which are pretty weak even on the surface.&lt;p&gt;One thing the military does&amp;#x2F;did to communicate with subs is use low-bandwidth text-only very low frequency radio, but you need colossal transmitters and there&amp;#x27;s no way the mother ship carries one. Hydrophones are also an option, and IIRC NATO even has a working sound-based modem to transmit digital signals to subs, but not sure if that has spread in the civilian market.</text></item><item><author>systemtest</author><text>Is there some sort of underwater &amp;quot;GPS&amp;quot; tracker they can use to track the sub?</text></item><item><author>spatialaustin</author><text>David Pogue, who traveled to the Titanic with OceanGate last summer, has said that he was on the control ship when a previous sub was &amp;quot;lost for about 5 hours&amp;quot;.&lt;p&gt;Source: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;twitter.com&amp;#x2F;Pogue&amp;#x2F;status&amp;#x2F;1670835763536183297&quot; rel=&quot;nofollow noreferrer&quot;&gt;https:&amp;#x2F;&amp;#x2F;twitter.com&amp;#x2F;Pogue&amp;#x2F;status&amp;#x2F;1670835763536183297&lt;/a&gt;</text></item><item><author>carbine</author><text>I&amp;#x27;m hesitant to speculate but just sharing -- an earlier version of this submersible was scrapped:&lt;p&gt;&lt;i&gt;&amp;quot;OceanGate will take advantage of lessons learned during the construction of its carbon-hulled Titan submersible, which was originally built for Titanic journeys. Rush said tests that were conducted at the Deep Ocean Test Facility in Annapolis, Md., revealed that the Titan’s hull “showed signs of cyclic fatigue.” As a result, the hull’s depth rating was reduced to 3,000 meters.&lt;p&gt;“Not enough to get to the Titanic,” Rush said.&amp;quot;&lt;/i&gt;&lt;p&gt;Source: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.geekwire.com&amp;#x2F;2020&amp;#x2F;oceangate-raises-18m-build-bigger-submersible-fleet-get-set-titanic-trips&amp;#x2F;&quot; rel=&quot;nofollow noreferrer&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.geekwire.com&amp;#x2F;2020&amp;#x2F;oceangate-raises-18m-build-big...&lt;/a&gt;</text></item></parent_chain><comment><author>Prickle</author><text>Military submarines also have a towed communications buoy that they can use to communicate with satellites. But that thing is connected to the submersible via a cable.</text></comment>
<story><title>Titanic tourist submersible goes missing with search under way</title><url>https://www.bbc.com/news/world-us-canada-65953872</url></story><parent_chain><item><author>minedwiz</author><text>Communicating with submarines is actually a nightmare. The saltwater ruins most radio communications, so you have no chance to receive GPS signals, which are pretty weak even on the surface.&lt;p&gt;One thing the military does&amp;#x2F;did to communicate with subs is use low-bandwidth text-only very low frequency radio, but you need colossal transmitters and there&amp;#x27;s no way the mother ship carries one. Hydrophones are also an option, and IIRC NATO even has a working sound-based modem to transmit digital signals to subs, but not sure if that has spread in the civilian market.</text></item><item><author>systemtest</author><text>Is there some sort of underwater &amp;quot;GPS&amp;quot; tracker they can use to track the sub?</text></item><item><author>spatialaustin</author><text>David Pogue, who traveled to the Titanic with OceanGate last summer, has said that he was on the control ship when a previous sub was &amp;quot;lost for about 5 hours&amp;quot;.&lt;p&gt;Source: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;twitter.com&amp;#x2F;Pogue&amp;#x2F;status&amp;#x2F;1670835763536183297&quot; rel=&quot;nofollow noreferrer&quot;&gt;https:&amp;#x2F;&amp;#x2F;twitter.com&amp;#x2F;Pogue&amp;#x2F;status&amp;#x2F;1670835763536183297&lt;/a&gt;</text></item><item><author>carbine</author><text>I&amp;#x27;m hesitant to speculate but just sharing -- an earlier version of this submersible was scrapped:&lt;p&gt;&lt;i&gt;&amp;quot;OceanGate will take advantage of lessons learned during the construction of its carbon-hulled Titan submersible, which was originally built for Titanic journeys. Rush said tests that were conducted at the Deep Ocean Test Facility in Annapolis, Md., revealed that the Titan’s hull “showed signs of cyclic fatigue.” As a result, the hull’s depth rating was reduced to 3,000 meters.&lt;p&gt;“Not enough to get to the Titanic,” Rush said.&amp;quot;&lt;/i&gt;&lt;p&gt;Source: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.geekwire.com&amp;#x2F;2020&amp;#x2F;oceangate-raises-18m-build-bigger-submersible-fleet-get-set-titanic-trips&amp;#x2F;&quot; rel=&quot;nofollow noreferrer&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.geekwire.com&amp;#x2F;2020&amp;#x2F;oceangate-raises-18m-build-big...&lt;/a&gt;</text></item></parent_chain><comment><author>scarnz</author><text>I concur. Message is authentic.</text></comment>