In March in the Gulf of Mexico in 3180 m of water, seven acoustic runs were conducted over a two‐day period. A directional source was suspended, at 80‐ and 360‐m depth and below a duct, from a surface ship that was essentially in a drift mode. An omnidirectional receiving hydrophone was towed at 3 kt at depths between 70 and 330 m and from 0.8 to 12 km. The acoustic energy was propagated in the form of 120‐msec CW pulses at 380 and 258 Hz, alternately, every 15 sec. During these opening and closing range trials,X‐BT's were taken at the receiving ship. Analysis for the received pulse levels was restricted to those coming via the refracted only and surface‐reflected propagated modes. Comparisons made of ray‐trace calculations from several models of the predicted acoustic signal levels with experimental results show good agreement through the Lloyd mirror interference regions with somewhat lesser accuracies for single path arrivals at the maximum ranges.