As the OVM 12 wrecksite lies between a depth of 35 to 40 meters, we dive with Surface Supply Equipment (SSE) and surface decompression. Normally scientific divers use scuba equipment, but because of safety regulations and to extend dive times we use SSE. The chamber ensures a safer decompression (as it is in a controlled environment) and allows us to spend more time under water. With SSE the divers are connected with an umbilical cord to the surface. This umbilical has three tubes: one with communication and film, one with air and one with the pneum. We dive with two divers at once.
First the divers put on their suits, jacket and helmet. The divers equipment is then checked. There is always one diver on standby in case something goes wrong.
The divers go down to the wrecksite in a cage. On the surface the umbilical cords are tendered.
From the dive control room the dive supervisor can talk to the divers and watch the footage from the cameras on the diver’s helmet. The dive supervisor can measure the depth the divers are at by using the pneum.
While at the wrecksite the divers have half an hour to take measurements, make drawings and/or film with the GoPro. Due to the relative short time under water the objectives for each dive have to be clear. Each morning all the divers are briefed and the goals for that day are discussed. In the evening there is a debriefing. All the measurements are added into the computer program Site Recorder. This program creates a site plan, based on the measurements from the site.
When the divers are back on the surface they have to get out of their diving gear and be in the decompression chamber in under 3 minutes. When in the chamber they will breathe pure oxygen to get rid of all the excessive nitrogen in their body. Depending on the time and depth spent under water, the decompression process usually takes 30 or 40 minutes. Once out of the chamber the divers have to wait for 4 hours to dive again.
This morning a filmcrew from RTV Rijnmond came by to see what we are doing. See:
Check in tomorrow to find out what all this diving has led to: our first findings and interpretation.
Robert de Hoop (intern Maritime Program)