What the %*@& is an umbilical re-termination you ask?
Well...
Information and commands from the pilot's computer are relayed to the rov by a serie of cables. It goes like this (in a very simplify version) :
joystick -> computer -> winch rotating junction box -> umbilical -> cage rotating J box -> tether -> rov
A lot of strain is put on the first 15m of the umbilical, because it's the part that holds up the cage/rov when it's lowered in water and hoisted back on deck. The cable is 7cm thick and metal armored, but still, every 6 months, we have to cut back part of it, and re-plug it to the j box. If we don't do that, the fiber optics and smaller wires start to bend and break and we lose signal.. not exactly a good situation when the rov is 100m deep and all your screens go black...
Sounds easy enough, but the un-biblical is not just one cable.. it's about 7 millions small cables all twisted together, in 4 millions different protective shields, coated in anti-corrosion goo and enclosed in a metal casing... kinda like this, but bigger :So, we cut back the damaged part, take the metal shield off on a length of about 70cm, then separate, clean and strip all the wires. Each end is then fitted with a little metal hoop except for the 5 @#&%$* fiber optics who are a whole other story I won't get into right now, that will be screwed on individual connectors in the junction box.
Since we had to unplug the umbilical to take the rov to the shop, it seemed like a good time to do the re-term right now instead of waiting for its due date next month.
So tomorrow I'll be swearing a lot, trying to pry out all the flimsy teeny wires out of their shields without breaking them :P
Friday, February 20, 2009
ROV 101
Posted by Bluefairie at 6:51 PM
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