Short Answer: Depending on your survey type and environment, non-conductive anchors and flotation materials can be used to keep your marine cables in place.
Long Answer: Different survey situations and environments will call for different methods to keep your marine cables in place. For instance, if you are surveying in a coral reef environment, then you should not use anchors since they could negatively impact the habitat.
In general, the best way to run a floating cable is in calm flat water with low water current and wind using a rope pulling on either end from the cables molded-in anchors. This works well on a pond or across a slow-moving river. Anchoring floating cables on open water is very difficult and involve multiple anchors and ropes.
To prevent drift on towed marine methods, it's best to run the system into the water's current if it is a significant current. An example of this would be to profile while moving upstream. For wind drift, you should use low-profile floats such as small fender buoys or closed-cell foam tubes to minimize the wind's effects.
Closed-cell foam tubes such as the ones pictured above will help your cables float and give stability in most situations. They are also ideal because they won't soak up water. Simply cut to the necessary length that you need. We often recommend brighter colors for maximum visibility.