Shipwrecks evoke feelings of nostalgia and awe in divers, but until you’ve dived one, it’s difficult to imagine. Here we take you step-by-step through the techniques you need for successful wreck diving.
#1 Be Prepared
Some wrecks are advanced dives, and dive operators will often make sure you're comfortable with deep dives and less-than-perfect conditions before they'll sign you up. An advanced-open-water certification or a logbook showing a recent history of similar dives will usually get you an OK. Some operators may require you to do a shallow-water reef trip as a checkout dive before allowing you to join an advanced wreck charter. Whether the wreck is a fairly shallow and easy dive or a deeper, more advanced dive, pay attention to the dive briefing to make sure you understand the dive plan, find out about conditions on the wreck, etc. Discuss the dive plan with your buddy.
#2 Get In and Down
On deeper wrecks, dive operators sometimes use a combination of lines to get you from the stern of the dive boat to the deck of the shipwreck. A trail line has one end tied to the stern of the dive boat with about 50 feet of line tossed out behind the boat and a float attached to the other end. The current will carry the float out behind the boat so divers will have a line to hold onto when they jump in. A tag runs from the stern of the boat to the mooring line. There are two setup variations. The more common variation runs along the water's surface. The second, often used in rough conditions, is a weighted descent line on the stern of the dive boat with the tag line also attached to the weight and running to the mooring underwater. If a mooring line is used by the dive boat operator, use it. Hold it with one hand (if permitted, wearing gloves is a good idea). Stay with your buddy and go hand-over-hand down the mooring until you get to the wreck.
#3 Explore the Wreck
Take note of your starting point. This is where you’ll want to end your dive. If there’s current, determine its direction once you're on the wreck. You can actually use the current as a tool in many cases by turning your dive up current from your exit point. Also, stay close to the wreck – it’s a safety precaution, but it’s also the best place to see the macro creatures that have set up housekeeping on the superstructure.
#4 Photograph the Wreck
It usually takes a wide-angle lens to photograph an entire wreck. A strobe is also very important. While some ships are shallow enough to shoot in available light, with or without filters, and other wrecks might be captured with an available-light “establishing shot” from a distance to show the general profile of the vessel, the photos taken on deck should be lit by strobe.
#4 Make Your Ascent
Two factors should limit your wreck dives: the no decompression limit and your available air supply. Manage both using the rule of thirds. You should use a third of your available time limit or air — whichever comes first — to swim away from your exit point, a third to return to the exit point and a third for delays or emergencies. Once you make it back to your starting point, use any remaining time to explore around the mooring, keeping the mooring line clearly in sight until it's time to go up.
#5 Back to the Boat
Once you've completed your safety stop, surface and use the tag line to move to the dive boat's stern, or just let the current take you to the trail line. Once you grab the trail line, continue down current so you're out of the exit area, inflate your BC and wait for your turn to exit.
Please note: Do not enter a shipwreck unless you have been properly trained in technical, full-penetration wreck diving. If you want to get started on this training, try an introductory wreck diving course. Look for an instructor experienced with the wrecks you will want to dive on, and try to take the course with the buddy you will dive with. Details between courses will vary, but they typically run two or three days, including three or four dives. Subjects include navigating outside a wreck and making a survey, pros and cons of artifact collecting, identifying and dealing with hazards, using lights, communicating with buddies and usually, at the end of the course, making a short penetration of the wreck. The tips here apply to diving on the external parts of sunken vessels.