Story and photo by mnsmarine
with additional text by Andrew Wong
The Marine Group had its first multimedia presentation on May 12, 2004 entitled, “Diving for Exploration”. Andrew Wong, also an MNS member, shared his insights with 19 members and 2 non-members about what motivates people to do technical diving.
Recreational divers usually dive to not much more than 20—30m. Beyond that point, the logistics and risks begin to require divers to possess training, experience, and specialised equipment to descend deeper than 40m.
Technical diving usually refers to diving in an overhead environment such as a decompression dive, underwater cave or a shipwreck – places where you can’t immediately begin to reach the surface. Shipwrecks are considered more dangerous of the two because the open ocean is a very dynamic environment, with issues such as tides, strong currents and the physical condition of the wreck itself.
Your choice of a technical diving instructor is paramount to your safety, and enjoyment of the sport. Obviously, there are risks involved, but an excellent instructor will be able to provide you with the necessary skills and knowledge to manage these risks. It is perhaps most important to ensure that your instructor does technical diving regularly, rather than just teach it, and proof of a systematic and rigorous approach to the diving is important.
Technical diving is more demanding than recreational diving. Depending on the depth and time required, you usually need at least a twin set (2 normal tanks joined together). You will usually use at least 2 breathing gases, and include the use of Helium. Good dive planning usually means you don’t dive alone, but usually have a team consisting of 2 or more divers, and depending on the conditions, a surface support team and divers on standby may also be required. In specific situations, divers may also choose to use specialised equipment such as scooters (a diver propulsion vehicle or DPV) to negotiate long distances or strong currents.
The world record for the deepest, longest, and most extensive cave dive took place in Florida and was done in a cave with water up to 100m deep, for a total dive time of some 15 hours. The resulting distance covered in the cave was approximately 6km. In the video presentation, we saw the amount of equipment these divers carried with them, and how they changed their tanks in the cave.
Because of the Second World War, Asia is a fantastic place for diving large wrecks that are still in relatively good condition. Shipwrecks are living museums and reefs, with fascinating histories. An example of the connection between history and diving is the two shipwrecks sunk close to each other on 10 December 1941. These were the HMS Repulse (240 meters long ~ 60m deep) and the HMS Prince of Wales (224 meters long ~70m deep) in waters off Pulau Tioman. It was the first time in history that an aerial attack was successfully launched on battleships at sea (the Japanese attack at Pearl Harbour was against ships in port). It was also the first major attack in the Japanese invasion of Malaya.
In April 2004, some of the same divers who dived the HMHS Britannic in 1999 (the Titanic’s sister ship 270 meters long ~ 130m deep), as seen in the recent Discovery Channel documentary, dived on the HMS Repulse over five days. They managed to reach new areas inside the wreck including the engine rooms by spending an incredible 50 minutes inside the ship. In the video of this dive, we saw the 15″ guns of the Repulse, a giant Marbled Ray, and footage from inside the wreck.
After the talk, group coordinator Saras Kumar presented a small token of appreciation to Andrew. Members who were interested to see some of Andrew’s equipment stayed behind for this section.