This was the fourth experiment under the program with the participation of Julia and Doncho Papazovi. The experience acquired during the previous expedition came very handy in the preparation for this one since it was much more complex and professional. The vessel used was shipping life boat long 8.5 m. with deck and a possibility for water drainageе. The deck was much more convenient and functional. The mast was higher, 7.5 m., the rigs was gaff and again with mainsail and jib. This time the boat was equipped with a short-wave frequency radio. The battery of the radio was charged by the engine. They also had permanent compass light, тор light and AC current for the radio. A serious ordeal was the permanent watch keeping at night since there were no automatic navigation tools. Julia and Doncho conducted scientific research and filled out tests. The nutrient intake was similar to that in the third expedition and was slightly improved to add liofizated fruit. Unfortunately, just like during the third expedition, they had problems with canned fresh water. The cans containing fresh water corroded and the taste changed. It is a great luck not to encounter any serious difficulties during a cruise of 14800 kilometers in the Pacific in a shipping lifeboat wading only 30 centimeters and with a first stop after Caliao at the Marquise Islands at a distance of about 8700 kilometers. Unfortunately, the worst of all possible things happened to Dju and Doncho. Initially, the radio antenna broke and it was impossible to fix it at sea. Thus they had no connection with the world and could not send a help signal. Later the rudder plate broke, and 1000 miles from Caliao during a storm the mast broke as well. It is difficult to believe but Dju and Doncho managed to cope with both problems. They made a new rudder plate using the remains of the old one, hoisted a new mast and adjust the sails to the renovated shorten mast. It is not necessary to go into details, but few people in their situation would handle such problems so successfully. It is a miracle that with such rig and diminished capabilities they managed to “hit upon” the Marquise Islands. But Dju and Doncho succeeded in that and successfully reached Hive Oa on the Marquise Islands on 10th of May 1976. It was only when they reached Tahiti that they were able to fix and replace the mast. The maneuvers around Samoa and Apia were made especially difficult by the strong drift and the lack of wind.