A sea and air rescue effort was going on late last night after two boats carrying scores of illegal immigrants sank in heavy seas off the coast of Evia yesterday. In the afternoon, a helicopter crew found three bodies. Earlier, a drowned man was found near Mantoudi. Coast guard officials said that at about 7 a.m. yesterday, residents at Kymasi near Mantoudi in northeastern Evia found a large number of illegal immigrants. Authorities, who detained 70 of them, said that the migrants had swum ashore after their boat began to take on water. None of the passengers knew how many had been aboard, raising fears of more drowning victims, beside the one found, as winds of up to 9 on the Beaufort scale were blowing in the area. Further south, near Hiliadou, 28 people (including two Turks who were alleged smugglers) were found. Their boat was found a mile off shore, half sunk.