Safety Stop required ?

[Kingpatzer]

I always say they're "required like motorcycle helmets." The law doesn't demand it. No scuba police will pull you over for not doing one. But if all that's between you and an undeserved DCS hit is 3 minutes at 15 feet, you'll really regret not doing it later.

[DivemasterDennis]

Good comments. I'd like to add a few more. First, my wife and I always do a safety stop on dives 40 feet or more, and if we have been doing repetitive dives over a number of days, we do them on every dive. Some dives end with diving in the shallows, and if we spend 3 or more minutes at 20 feet or less, that counts as our safety stop. A good example is in Bonaire, diving the Helma Hooker from shore. The dive is to about 90 feet or more, but the exit is a gradual climb up a 45 degree reef wall, the top of which is between 15 and 20 feet. Swimming around in the shallows and enjoying the animal behavior and colors at shallow depth makes for a great safety stop. When we have a safety stop when ascending from about 6o feet or more, we always look into the deep blue, during the stop and are often rewarded with sightings of rays, sometimes tuna or other predatory fish, and even an occasional game fish like a sail or swordfish, and the occasional shark. Safety stops are also good places to practice body control through different positional hovers. Making a practice of safety stops reduces risks on those occasions when you can't or don't make one. As a DM I have had to retrieve dropped gear at the end of a dive and not always had the time or inclination to do a full stop, especially if its the last dive of the day. But except for those occasions, I do. A safety stop habit is a good habit to have.
DivemasterDennis

[Hawkwood]

As you said you were doing your four OW dives, you had to have done one safety stop for 3 minutes at 15 feet. It is a requirement. Perhaps you did as Quero suggested, swam the safety stop. To bad it was not made clear to you.