Search technique depends on several variables. A circle search from a peg in the ground works if you have a smooth sea floor. Circle searches using a method an earlier poster described (sending down a weighted line tied to a cleat or other object near where you should be searching) is a really creative way to do a circle search as long as pilings, etc., don't interfere with the circle. Circle searches generally are best for small objects in poor vis, as I recall.
However, you might modify depending on the situation. If the object is known to be within a slip at a marina it's different than if it's in an open area with no clear boundaries.
