Scuba Diving Week 4

07/18/11

Week 4 of scuba diving provided us with a lot of useful information and we just practiced what we learned during week 3 of class.

They recommend taking the Diver Stress & Rescue course if we take any of the other SSI Continuing Education courses so that we are well prepared for the issue that can happen underwater. It is always stressed that if you don't feel well in any way that you shouldn't dive. You only want to dive if you are in your comfort zone. Another course that sounds fun is the Night & Limited Visibility Diving one since coral reefs appear very differently during the night. There is also a Navigation course that is recommended.

We discussed currents and how you should always dive against the current so that you don't need to expend more energy returning to the boat than you did going away from it. There is a "rule of thirds": use a third of your tank going out, a third coming back, and have a third left at the end of your dive. To see why you shouldn't dive with the current (and why you might want flags or whistles attached to your BC) Mark recommended watching the movie Open Water. Most diving companies that take you out have a tagging system to keep track of everyone and not leave a diver abandoned out in the water.

Waves and rip currents were discussed next. Rip currents occur when there is a bottleneck created near shore by unevenness in the ground beneath the water. The rule for these is let them carrying you out if you are starting your dive but if you are returning to shore you want to swim diagonal or perpendicular to the current.

Sharks was our next topic of discussion: "the pitbulls of the ocean" because they are misunderstood. You're in more danger at the surface of the water (such as surfing or boogie boarding) because the silhouette looks like a shark's favorite food: seal. When you're diving you are in the shark's element and they can see what you are which makes it much safer diving in shark waters than surfing or just swimming in them. There are videos of people free diving with great whites who don't come to harm and actually avoid any aggressive behavior by swimming at the sharks if they seem to be stalking another diver. Sharks don't really like humans as a meal and probably don't like a meal that isn't running away from it.

After telling us about fire coral last week we went over what is best to treat injuries from the organisms on the coral reefs. Hot water is the go-to first treatment before seeking actual medical help. This is because marine stings (unlike stings from land animals) are not directly harmful due to an injection of venom since the nematocysts they release are stinging cells containing the venom. Instead of activating them by wiping them away, hot water keeps the cells from springing into the skin and allows them to be rinsed off. This is also why wearing full wet suits is recommended even in warm waters.

For any diving injury pure oxygen should be administered. Even if it is a fire coral injury, the pure oxygen should be administered while hot water is being poured on the infected area. The second treatment for decompression injuries would be a recompression chamber which one wants to avoid having to use. Although a dive may go well and rules were followed, other factors can contribute to having the bends. It takes about 24 hours to really get the symptoms and know you have it.

After considering some of these issues that may result in having to seek medical attention, they emphasized the importance of having DAN (Divers Alert Network) insurance since it's pretty cheap at only $35/year. We are covered throughout our class until we are signed off.

The water portion this week was review. We did learn how to manually inflate our BCs. Ashley learned how to swim with one fin since she sprained her foot the Tuesday before and it was swollen like a sausage. Next week seems to be the week we will actually play more.