sealed, it cannot be safely retrieved to the surface. Recovery of saturation divers in such a case can be done by lowering another bell close to the disabled bell and transferring the divers through the water to the rescue bell, which is then sealed and recovered and locked on to the surface chamber in the normal way, after which the empty bell can be lifted by whatever means are available, for repair. A similar procedure may be used if for any reason the bell cannot be lifted. In the case of an open bell that cannot be raised the divers will abandon the bell by a method which depends on the type of bell. A wet bell which does not have a bell umbilical is the simple case as the divers are supplied direct from the surface through individual umbilicals which pass through the bell. The divers simply pass through the bell following their umbilicals and ascend to the surface assisted by the surface tenders. Any decompression required can be done in the water, or if there is a suitable hoist, surface decompression in a chamber may be practicable. If the divers are using excursion umbilicals supplied from the bell, they may not be long enough to reach the surface, and it may be necessary for the surface standby diver to meet them in the water and switch them over to umbilicals directly supplied from the surface. Rescue of saturation divers Rescue of saturation divers may be necessary in several possible scenarios: A diver working at the bottom may need to be recovered to the bell by the bellman The divers on a bell run may be stuck at the bottom because it is not possible to lift the bell. This is unlikely as there are usually alternative methods of lifting available. The divers may be unable to get the bell to seal and hold pressure at the end of the dive. The divers in the saturation system may be in danger from an uncontrollable hazard such as fire or imminent sinking of the platform Any rescue of saturation divers is logistically complicated by the absolute barrier that they must remain at or very near their saturation pressure at all times until they can be decompressed according to a suitable saturation decompression schedule. This means that they must transfer from whatever environment they occupy at the time of the emergency,