Navigating Underwater Without a Compass
There's already a lot to remember when scuba diving so it's no surprise that divers, especially new ones, struggle with navigating underwater without a compass i.e. natural navigation. Fortunately, natural navigation isn't all that difficult -- it merely requires knowing a few things to look for and paying attention to underwater cues.
Map Out the Dive Site
Getting even a simple sketch of the underwater terrain can go a long way with helping a diver orient himself underwater. Coming upon a feature is a lot more useful when you have some idea of it's relationship to other important features of the dive site. The most basic maps include contours of the shoreline or area, depths, and major features. Adding detail such as the types of bottom terrain, vegetation, and marine or aquatic life.
When using underwater features to navigate you can look for 1) unique features or 2) features arranged in a unique formation. For example, a bunch of seaweed is likely to be indistinguishable from another bunch of seaweed, but if combined with a grouping of rocks it may be sufficiently unique to use for navigation. Throw in additional information such as depth, and you increase the uniqueness of the feature.
Ripples in the Seabed
Although the only occur in relatively shallow depths, ripples in the sand are a good indication of which way the shore is i.e. they orient themselves parallel to shore.
The direction of the current can be another navigation aid since it's something that can be felt throughout a dive. Of course, tidal currents change throughout the day so be sure to understand how to interpret those changes.
Look at Where You Came From
If you've ever hiked, you've probably encountered the situation where your return path wasn't as obvious as you expected it to be. That's because the trail's twists and turns can make features visible in one direction and hide them in another. Similarly, when scuba diving, the view when traveling in one direction can be sufficiently different as to disorient you if you're not looking behind you as you move through the waters.
So yes, the newness, sensations, and distractions of diving can be quite overwhelming. Still, with the tips above along with a keen eye, you can navigate underwater as if you had a compass in hand.