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1. Embed this notice
   goatsarah (goatsarah@thegoatery.dyndns.org)'s status on Saturday, 01-Jul-2023 19:27:39 JST goatsarah

   Am I missing something about the Titan sub?

   He used a carbon fibre pressure vessel. Carbon fibre is a material that’s good in tension. Is has no strength in compression at all: it’s just woven cloth.

   It works as an aircraft pressure vessel because the pressure inside is higher than the pressure outside, hence the carbon fibre works as a balloon and is in tension.

   But for a submersible, the pressure outside is higher. The pressure vessel is getting compressed.

   So the carbon fibre will give it a bit of stiffness, but the actual crush resistance is being provided by the epoxy resin that holds the carbon fibre weave together.

   Am I missing something? Why the hell did they build a compression pressure vessel out of string glued together? It doesn’t matter how strong the string is: it will still fold up if you scrunch it into a ball. The structural strength came not from the string, but from the glue.

   I’m amazed it took as long to fail as it did. I must be missing something here, right?

   Why, for the love of all that’s holy, did they use carbon fibre?

   • Embed this notice
     Uraael (uraael@blahaj.zone)'s status on Saturday, 01-Jul-2023 19:33:59 JST Uraael

     in reply to

     @goatsarah@thegoatery.dyndns.org
     
     The answer to this lies in where the design originated. It was developed by adventurer Steve Fossett as a ONE-TIME submersible, which would have suited what he was using it for.
     
     The company that now owns the design supplemented this with an active sensor system that would warn when any area was going to degrade/breach (apparently Carbon fibre degrades after every usage?). It either didn't work or the crew had no time to react to that information.
     
     There's a brilliant thread about it somewhere. Will see if I can find it.

   • Embed this notice
     goatsarah (goatsarah@thegoatery.dyndns.org)'s status on Saturday, 01-Jul-2023 19:33:59 JST goatsarah

     in reply to

     • Uraael
     @Uraael so it was literally a single use plastic bag?
   • Embed this notice
     goatsarah (goatsarah@thegoatery.dyndns.org)'s status on Saturday, 01-Jul-2023 20:03:29 JST goatsarah

     in reply to

     • Bethan M. Jenkins
     @gwenynen A life-expired, single-use plastic bag.
   • Embed this notice
     Bethan M. Jenkins (gwenynen@toot.wales)'s status on Saturday, 01-Jul-2023 20:03:31 JST Bethan M. Jenkins

     in reply to

     @goatsarah I also heard - though don't know how true it is our how much bearing it has - that he got the CD cheap as it was old stock and possibly out of date 😬