Drift diving or anchorline drifting and the new experiences it can offer are discussed. Techniques and safety rules for learning this new skill are given. Skill and experience are important factors that will spell the difference between an enjoyable an a miserable drift dive.

Have you ever wondered what a worm feels like, wrapped around a hook and trailed through the water? You can find out – try drift diving while hanging on an anchorline!

Later in this article you will learn “normal” drift diving techniques but, for the adventurous, here’s a new twist. Pick a no-swell day, the flatter, the better. Lower the boat’s anchor to a pre-determined, sensible depth and tie it off. Cut the engine. A buddy pair enters the water and swims down the anchorline. As the boat drifts with the surface current, it drags the divers who are hanging on the anchorline, above the anchor. Don’t get too close to the anchor, if it jerks in a swell, you’ll get clobbered.

While streaming through the water, you may see amazing things. One day around the Southern California Channel Islands I played worm and was greeted by amorous sealions (skip the rookery areas during mating season) and a school of Yellow Fin Tuna. The tuna encircled the anchorline, parading around and around. Smaller fish will appear out of nowhere, perceiving the boat to be a giant bit of flotsam and a new home.

If you are drifting over a slopping bottom contour, the biggest fish common to the area may be cruising, looking for food. It is a little scary hanging mid-water and not clearly seeing what comes swimming out of the haze. To enjoy anchor sitting you need a flat ocean so you aren’t being yanked up and down, risking air embolism and sacrificing the best possible visibility.

My most memorable anchor drift dive was the day porpoises came leaping by, stopped in their tracks and came back to frolic around those of us clutching the anchorline.

With limited space, anchor sitting is for one buddy pair at a time. Both divers descend and ascend at the same time, using the anchorline. The deck crew tracks the pair’s bubbles and is prepared at all times to start the engine and pick up the divers, if they drop off the anchorline. Divers should take full gear, including instrumentation on this type of dive. Your air consumption will be different (slower if you are really calm and faster if you are apprehensive or excited) and you will probably maximize your bottom time. As an added safety precaution, carry a surface signaling device – whistle, inflatable float, strobe light, etc. – in the case you surface and the crew does not see you.

Anchor sitting is definitely an advanced boat handling, divemastering and diving activity. It can be incredibly boring or the ride of a lifetime.

If you are not quite ready for anchorline drifting, try some tamer drift dives to build your confidence and skills. Drift diving, usually enjoyed along a vertical wall, lets the current propel you through the water. Since the best reef viewing is from the side or when looking up, drifting along a wall lets you set your best viewing angle. It is ecstasy to be weightless, flying along with a minimum of effort.

Drift diving with currents

Several factors affect how and where to go drift diving: 1) The water clarity (it’s no fun to go bump in the haze); 2) The current’s strength (it’s not handy to have your mask ripped off); 3) The experience/ability of each diver (there’s no way to wait for someone having problems); and 4) The competence of the boat skipper. Drift diving is almost always a boat dive, because the logistics and prudent safety precautions for shore-based drift dives are onerous.

There are several methods commonly used to drift dive. Which one you select will depend upon the environmental conditions and the experience level of the divers. Different areas require drift dives be executed in ways best suited to that environment, the type of boat and the typical skill of the divers. Be certain you understand the how-when-why of the divemaster’s pre-dive briefing. Each participant must be able to implement the plan or the dive will fall apart and must be aborted.

For the most enjoyable, safest drift dives, choose your group carefully. The adventure can only be as thrilling as the least capable diver can manage. If you are very experienced and go with people who have buoyancy, ear or gear-use problems, you are going to have a frustrating, disappointing dive.

Before you pay to go on the boat trip, ask the operator pointed questions about the experience of the other divers. If you are not satisfied with the answers, or are concerned from your own observations of the other divers, don’t go. You are not an egoist – you are a realist about your personal safety, enjoyment and financial investment. This caution is not meant to discourage you from drift diving or to put down beginning divers but rather to maximize the fun of diving and decrease the aggravation potential.

Float Or Buoy Drifting

Float or buoy drift diving gets its name from the float used on the surface to mark the moving location of the group. A typical dive would include the following:

* A pre-dive briefing on the boat.

* All divers suit up and do a thorough buddy check.

* The boat is not anchored.

* When all divers are ready to jump in, they enter the water as quickly as possible and stay together at the surface float until everyone is ready to descend.

* The lead divemaster holds onto the float’s downline and descends to the selected depth, followed by the divers descending as a group on the downline.

* At depth, the divers drop off the line and drift along at the same depth as the lead divemaster.

* The lead divemaster holds onto the downline and float.

* The rear divemaster, the last diver down the line, takes a position at the end of the group.

* Some resorts use a second float at the rear, carried by that divemaster.

* It is the responsibility of each diver to stay in sight of the lead divemaster, at the prescribed depth. There should be no stopping.

* When a diver reaches the pre-agreed upon amount of air, typically 1,000 psi, the buddy team begins working its way through the group to the line, signals the lead divemaster that they are low on air and OK. Then the pair begins ascending, lightly holding the float’s line.

* Once on the surface, the divers inflate their BCs and give an over the head OK sign to the chase boat.

* Pick up procedures vary, but one system is that as soon as the OK sign is returned by the boat crew, so both parties have acknowledged seeing each other, the divers let go of the float line and begin moving away from the buoy.

* The boat approaches the buddies for pick up as soon as they are safely away from other ascending and waiting divers.

* Other boats prefer that divers wait at the buoy as a group and only let go in pairs, once all divers are on the surface.

Float or buoy drift diving works really well for groups of up to a dozen divers in low or moderate currents. As you might imagine from the procedure’s description, the dive turns into a tangle if someone cannot clear his/her ears or won’t maintain buoyancy at the agreed upon depth. Stopping and holding onto the reef quickly separates you from the group, which is a problem. Divers ascending off the line risk being hit by the boat motoring behind the group.

Night diving in current is commonly a float drift dive. The experience level and confidence of the divers needs to be higher and lights are required. Divers attach chemical lights to their tank valves, plus attach turned on lights to both ends of the float’s downline. The lead and rear divemasters need to have unique lights, so they can be differentiated from all other divers. An easy way is to attach two chemical lights to the lead divemaster and four to the rear divemaster. Before attempting night drift diving, divers should have separately mastered night diving and drift diving.

Live Boat, Free Drift Diving

Sometimes the most practical option is to let the divers descend to depth, float along freely and have the boat watch for bubbles while trailing behind at a safe distance. When there is a likelihood a float and line might become entangled in pinnacles, kelp or other obstructions, live boat drift diving is common. More experienced divers enjoy the greater freedom of drifting without lines. That freedom depends upon divers of similar abilities, committed to staying together at a chosen depth, following the lead divemaster and using about the same amount of air. This author has concluded that free drift diving is a terrific small group activity (four to six divers).

The boat skipper and crew should be alert and on watch with their group in the water. The boat should not leave the area for any reason. The boat crew watches for bubbles and tracks the group’s movement. It is especially important to notice if bubbles remain stationary or leave the rest of the group – these are emergencies in the making.

Chase boats frequently drag a current line off the stern. It takes crew awareness not to back down over the trailing line and wrap the prop. If possible, the boat needs a way to warn divers underwater that something has changed and to surface. Such events might include an accident, a sudden and dramatic change in the weather or a boat breakdown. An underwater recall unit such as the ones required on charter boats in Los Angeles County, California can be used to recall divers to the surface.

When returning to a live boat trailing a current line, wait on the surface for the skipper to swing the line close to you. Grab a hold and be prepared to decrease the volume in your BC. Kick on your stomach, pulling with your arms to work your way up the line. You will be pulled through the water as the boat continues to drift after it cuts power. Get streamlined and hold on. Stay on your stomach so you can lift your head up and see the crew on the stern. If you roll onto your back, your arms will stretch out, the line go over your face and possibly get entangled in your equipment – all with nasty results. Stay on your stomach!

Don’t panic if the boat doesn’t come to pick you up immediately. If the crew has acknowledged seeing you and exchanged over the head OK signals, just slightly inflate your BC and wait. With several buddy pairs in the water, the crew must evaluate the safest order for the pick ups, which may not be in the order divers appeared on the surface.


Drift diving is a popular advanced boat diving activity. It is great fun and allows you to see more territory while experiencing the feelings of being in harmony with the movement of the ocean. There is a gentleness that can be enjoyed when you glide above a seascape while barely kicking a fin. There is also an adrenaline rush that comes from hanging on a line and feeling like a flag on a pole on a windy day. Whatever the drift diving technique used, it is a way to “get down and get high” on the beauty and adventure of scuba.


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