>I have often been asked what it takes to dive wrecks safely or what training a diver should pursue to enjoy wreck diving, and my answer is always, "It depends." Many dive professionals have heard the following stated earnestly by an overzealous new diver: "I was hoping to dive the Andrea Doria or the Britannic — what do I need to do?" My answer to this statement is also consistent: "How many years were you planning to train for the dive?" It takes a while to work up to a low-visibility, cold-water, high-current, offshore, custom-blended-mixed-gas wreck dive; you have to master each component before trying to tie them all together.
>Let's face it, many wrecks are on the bottom because the surface conditions in the area were, at some point, less than ideal. Some of the most interesting historical wrecks are situated in especially challenging dive conditions. Divers wishing to visit these wrecks should be comfortable with high current and surge. This means lots of experience diving in the open ocean and good physical fitness. A giant stride from a pitching boat into turbulent waves can be daunting, but getting back onboard at the dive's end can actually be more physically challenging — and dangerous. You need to be able to haul yourself, your gear and 30 extra pounds of water weight back up the ladder as well.
>Strong Currents, Big Waves
>Every effort should be made to have equipment that is proper for the dive and streamlined to reduce drag, thereby reducing the effort required of the diver. Think you're in great shape and this doesn't apply to you? The fact of the matter is you are fighting physics as well as your physiology. As gas density goes up with increasing depth, carbon dioxide (CO2) retention also goes up with increased effort or work at depth. With an increase in CO2 retention, your likelihood of passing out from hypercapnia (excess CO2) or a seizure also increases. (Excess CO2 can predispose divers to seizures when using any gas mixture with a high partial pressure of oxygen.) Overexertion at depth has killed many divers via both mechanisms and is something to be avoided at all costs. A highly skilled diver will expend far less effort to move through the water than a brand new but highly fit diver. The best scenario: Be both experienced and in good physical shape with properly streamlined equipment.
>Speaking of overexertion, recent research indicates diver mortality from cardiac events is a growing concern, and various means of addressing this concern were the subject of heated debates at the 2010 DAN® Recreational Diving Fatalities Workshop. Overall fitness should not be taken lightly; if you are concerned about your cardiac health, talk to your doctor, or call DAN for a referral to a doctor trained in dive medicine. If you are over 40 or have cardiac risk factors such as long-standing high blood pressure, a history of tobacco use, heart disease in the family, diabetes or other medical conditions, you can't go wrong getting evaluated.
>OK, you work out regularly, don't smoke, keep up with your health concerns, have streamlined your gear so an occasional fin stroke keeps you ahead of the divemaster and have logged 82 Caribbean and offshore dives in the last three years. So what do you need to be concerned about down on a wreck?
>The Hazards of Wrecks
>Wrecks present unique hazards for those diving the outside as well as the inside of the structure.
>Inside a wreck there are other concerns: metal rusting to razor-sharp edges, rooms turned to impossible and disorienting angles, furniture lying in jumbled heaps and wiring that your shears won't cut. Insulation may fall from a ceiling, blocking a passageway while simultaneously dropping the visibility to millimeters, or an errant fin stroke might mix the paint on the walls with the water in the room, giving it the consistency of blue milk and forcing you to find a way out by fingertip. A 700-pound goliath grouper could suddenly realize you just swam into the room he was napping in — and that you are floating in front of the only exit. All these are real-world pop-quizzes I have enjoyed in the past. It turns out training for the worst-case scenario pays off every now and again, so pay close attention to your carefully chosen wreck instructor. Wreck diving can be done safely but requires training, experience and the right equipment. Don't shortcut any of these prerequisites, or you risk failing one of those quizzes.
>So you got trained, practiced, got your gear up to speed, and your buddy calls. He has booked a trip out to that wreck you've been chatting about forever. A few days later, you drop down into the depths, find the wreck, explore it and are ready to ascend. The current has picked up, so you and your buddy blow lift bags from the top of the structure before you drift off into the wild blue yonder. You release the bags from a down-current rail to ensure they, and eventually you, don't get entangled in the superstructure during ascent. Maybe you racked up a few minutes of planned decompression — no drama, you are trained and equipped for it. Twenty minutes later you have completed the dive and are on the surface — more than a mile away from the boat in a three-knot current.
>Getting Back on Board
>If you didn't anticipate the possibility of being alone in the open sea, your dive planning was, ahem, incomplete.
>© Alert Diver — Fall 2011