SMP&rsquos well established manufacture and design team have recognised the requirement of the next step to extended bottom times with air nitrox and mixed gas diving with the ever increasing demands in the renewable oil and gas sectors in the offshore industry. SMP have come up with a design for a closed Bell TUP System which will be a unique one-off design available to all interested parties.
The system provides a cost effective diving solution through increased bottom times for the diving teams. This provides the capability for the diving team to be working from a Schedule 6 type Bell whilst the second team will be in decompression after completing their bell diving operations. This will mean continual productivity from the diving bell teams with less down time and smaller diving crews that would be applicable for normal air and nitrox diving.
Closed Bell Diving Description
SMP propose the utilisation of a minimum 4.5 m3 saturation diving bell which has the capability of bounce diving diving operations. This is critical to the utilisation of this system. The diving bell can be lowered to the seabed under atmospheric conditions. When the divers arrive at the work site the supervisors will have the capability to pressurise the diving bell equivalent to the work site depth which will allow the divers to exit the bell to proceed with their work tasks. This can be a single diver or two diver lock out with a stand by diver remaining in the bell.
On completion of the dive the divers will return to the diving bell where the doors will be sealed. At this stage the divers in the bell will start their decompression procedure. The bell will then be recovered to the surface with the divers continuing their decompression within this controlled atmosphere. The bell will be recovered by the handling system into the bell capture arrangement thereafter manipulated onto the bell handling trolley for mating to the divers transfer lock.
The above process allows for much greater productivity with diver&rsquos bottom times a more controlled and safer working environment and quicker and safer decompression procedures as opposed to the regularly used oxygen surface decompression procedure.
Deployment of the Diving Bell
The diving bell will be deployed either through a moonpool or over the side of a vessel using this gantry type handling system utilising a main bell winch and lift wire as the primary means of lifting the bell and additionally a clump weight system for secondary recovery. Both winch systems will be hydraulically driven by twin integral hydraulic powerpacks utilised to drive the complete bell handling gantry system. Additionally the main bell umbilical will be handled by a dedicated hydraulic umbilical winch and HPU.
The deployment system will recover the bell from depth into the bell catcher system position the bell over the mating trolley lower the bell into position onto the mating trolley and move the bell to the mating position for the bell mating clamp to operate and make the seal between the bell and the TUP.
Once the seal has been made between the bell trunk and TUP the dive crew from the bell will transfer into the TUP to continue their decompression. This crew will then enter into entry lock number 1 for continued decompression. The TUP will be vented to atmosphere and a new 3 man dive crew will enter the divers transfer lock to transfer into the diving bell to start the next bell dive.
The bell will be sealed and will be deployed to the working depth for the work to continue again. During this period the first diving crew which enter lock number 1 will be relocated into lock number 2 to continue their decompression procedure cycle. The continuing 3 man crews can rotate on this basis which will provide maximum productivity without committing the diver to saturation.
Decompression Chamber Operations
All three locks (TUP chamber lock 1 and chamber lock 2) will be controlled and monitored from 3 independent life support control panels mounted on the side of the chamber complex within the confines of the container.
Diving Bell Operations
The diving bell operations will be controlled from a saturation style diving bell operators control panel from within the 40&rsquo container.
Bell Deployment Handling Operations
This operation will be carried out from a remote location on the bell handling system but monitored from the bell dive supervisor&rsquos control panel.
System Exo-Structure and Bell Mating Trolley
This exostructure will act as a heavy duty crash protection frame mounted around the 40&rsquo ISO type container. This frame will include all the necessary lifting lugs and ISO corner castings to allow for ease of transportation. Please note that this structure will be a wide load and special clearance will be required for shipment on public roads.
The exostructure will allow for the 40&rsquo ISO structure to be mounted inside and the structure will act as the main support for the bell winch package and bell handling system.
Mobilisation and Demobilisation
This modular system is easily transported and mobilised to provide fast offshore operations on any suitable operation or vessel of opportunity.
Twinlock Decompression Chamber
IMCA D018 D024
5 Bar 50 msw
(but can be re-rated to 18 mtrs (590 fsw)
Diving Bell 3 Man
Victoria Machine Works
Chamber Lock 1 (entry lock)
18 mtrs (590 fsw)
x 2 Aluminium Benches
x 2 (bottom side)
Diver Transfer Lock
Chamber Lock 2 (main lock)
Ocean Systems Inc
2.22m (Dia) x 2.53m (H)
x 2 Aluminium Benches
2 x 600mm (24&rdquo) manways
1 x 400mm (16&rdquo) medical lock
1 x 300mm (12&rdquo) medi lock
3 x viewports (side)
3 x viewports (top)
Chamber is also equipped with chamber comms lighting gas analysis depth monitoring fire suppression system and CCTV monitoring.
Toilet Shower & Sink
L : 40&rsquo (12 mtr) x W: 11.8&rsquo (3.5 mtr) x D: 11.8&rsquo (3.5 mtr)
Weight: 38000 kgs
2 x Personnel Doors
2 x Heating and Air Conditioning Units
4 x Gas and Air Penetrator Plates
1 x Electrical Penetrator Plates
DDC and TUP:
Side Mating Manway and End Mating to SDC (Bell)
Divers Transfer Lock with toilet and shower facility
1.8 mtr Twin Lock Chamber for Diver&rsquos Decompression Treatment
Built in Master Control Panels
Capacity for 8 persons in the Twin Lock Chamber and 3 persons in the DTL
System currently rated to 50 mtr SWD but can be re-rated to 18 Bar 180 mtr (590 fsw)
Medical Locks and Chamber and DTL
Chamber and DTL outfitted with Comms Lighting Gas Analysis CCTV Systems CoolingHeating Scrubbers
LP Air Storage System
Fire Suppression System
Electrical Breaker System
Transformers and Battery Back Up Supply