...I can’t remember the procedure exactly but the transfer trunking was brought up to pressure and as it came close the bell door could be opened (chamber doors always work AGAINST) the pressure so they can never blow open. Once the wet pot door was opened then transfer under pressure (TUP) could start. The divers exited the bell and closed at least the wet pot door behind them. The wet pot is where they undress and leave their wet gear, before entering the living chambers (called the “bin” 1 deck below main deck. Doors in the system were closed afterwards so loss of pressure couldn’t travel through the whole system.
When the bell was launched, the divers TUP, and when both doors on the trunking were closed, the trunking was depressurised, the clamp opened, bell trolley moves backwards, the bell side door is closed, the cursor lowers to main deck level and the Deck Diver performs last minute inspections etc then he clears, the cursor lowers to the bottom and the bell continues on it’s own umbilical and wires from the bottom of the hull.
…In actual fact the bells are stabilised by a pair of guide wires, inboard and outboard of the bell which have a clump weight on the bottom. When the bell is at the bottom of the moonpool, the guide weights are lowered to a safe distance ABOVE the highest structure to be worked on. The ROV checks the deployment. Once they are in position, the bell is lowered down two guides down the guide wires and the ROV tells the winch operator to stop when they come within a few metres of the clump weights. Only when this is done and the all clear is given, then the castellated lock on the bell bottom door is opened and the door swung inwards into the bell. Diver No 1 can then enter the water.
So for the Seabex I’m not so sure because the only dodgy sketch I can see on-line shows a dive system very roughly similar, but with a slightly different moonpool bell(s) launched at the front end with a cofferdam separating them??? I know the Seabex One and the Seacom used to launch and recover things through the aft moonpool also though.
Worth noting anyway: Trunking for diver transfers was something like 600mm in diameter (measure your shoulders and think how tight that is, I used to struggle to crawl through when the system was vented for maintenance!). On the transfer trunking at the wet pot to bell flange, the surface had a stainless steel “sacrificial ring” bolted to it. Because the split clamps would slide across the back of the trunking and bell flanges, they would wear over time and the clamps would eventually fail to seal. The sacrificial rings would be changed out for thicker ones over times to maintain a good seal. When the wear got too much then the clamps themselves would be replaced, and a thinner sacrificial ring would be swapped back-in...
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Topic: Graupner Seabex One (Read 16829 times)