Diving well offshore is a pursuit many divers deny themselves, as a diver in the great beyond, miles from any known dive site the scope and realm of diving become infinite. It can allows you to become more at one with sea as you experience more of what the oceans have to offer.
Oceanic or ocean diving, by its definition, takes place well offshore and the shoal diving comments are equally applicable for ocean diving. Locating the dive site will almost always require depth finding / gps locators and an experienced coxswain / skipper.
Rescue from any potential accident will be delayed and in some locations there may not even be any rescue attempt possible! This alone should imply that divers are experienced veterans of the water. Dive plans should be agreed upon and stuck to. With no shoreline to aim for if in difficulty the use of cover boats is essential in oceanic waters.
In normal conditions there is no reason why separation of the divers should occur. The consequences of separation are dire indeed, it is necessary therefore for extreme caution and care to be taken when ocean diving. Consider the use of surface marker buoys mandatory with Delayed SMB's as a back-up. Mini-flares are recommended along with an SOS transmitter (sends a long distance signal to the coast-guard / Rescuers).
Tides at offshore sites are generally slight, although tidal streams and even ocean currents can be troublesome to divers in the water.
A swell is almost always present at ocean sites and can be deceptively large, since there are few reference points against which comparisons can be made. The abilities of the strongest diver can be quickly exceeded by even a moderate swell. The effects of a swell are most noticeable in shallow areas near the tops of shoals and these comments should be heeded. (see shoals section)
One of the exciting possibilities of ocean diving is that of seeing large, oceanic pelagic's such as sharks and whales. You are now entering their environment and anything may happen!
So far we have assumed that you will be diving on the seabed. However when attempting to dive with ocean creatures you may choose to enter the water the bottom is hundreds or even thousands of meters deep. The hazard now becomes obvious - that of sinking too deep and becoming overwhelmed by O2 toxicity / Narcosis. This is easier than many would assume, with a distinct lake of reference points and the water clarity, depth discipline and buoyancy skill become paramount. It is, therefore, essential that such 'on-the-edge' diving is left to divers who are very experienced and near-experts in their own right.
Ocean Diving - Cover boats
When diving at offshore sites the diver should be viewed as a team effort between the divers and their cover party. The divers must be locatable, as they are totally dependant on the cover boat to pick them up after their dive. Consequently, neither the boat nor the divers should do anything unplanned. Both must stick to the dive plan.
To aid in location marking the divers must use a surface marker buoy or, depending on the water conditions, a delayed surface marker buoy. They should carry whistles and flags mounted on extendable masts. The drift diving section has many points and tips relevant to Oceanic diving.
The boat used for covering the divers underwater must be in good condition and have a reliable engine, the comprehensive spares list in the boating equipment section of the Boat Handling page is a wise list to take heed from in Ocean diving. The coxswain should be a level-headed and salty sea veteran for this type of diving cover. Knowledge of the currents and weather conditions are important. Usually the cover boat will be operating from a 'mother ship' vessel and the two should be in radio contact. If there is a swell the divers may be invisible from the cover boat yet may be seen from the parent vessel.
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