What should be done if the bottom time exceeds the table limits without available contact with NEDU?

Using the U.S. Navy Thaimann Algorithm Dive Planner is the correct approach when bottom time exceeds table limits and there is no available contact with the Navy Experimental Diving Unit (NEDU). This algorithm provides a systematic method for assessing decompression requirements based on the actual dive profile, considering the depths and times involved. It allows divers to plan for a safe ascent while managing potential risks associated with exceeding the standard dive tables.

This method serves as a vital tool, especially in situations where other resources or support are unavailable. It incorporates more variables and can yield a more tailored decompression schedule than standard tables alone, which is crucial for minimizing the risk of decompression sickness.

The other options would not adequately address the safety and technical requirements needed in this situation. Ascending immediately to the surface might overlook critical decompression needs, potentially leading to serious injury or incorrect ascension protocols. Ignoring the exceeded time poses significant health risks without following proper procedures. Continuing to dive until symptoms develop is potentially life-threatening, as it disregards the importance of preventive measures and the principles of diving safety.