SOUTH Sea Development, a property and hotel development firm, has announced a two-thirds drop in profit to $20.7 million for the year ending March 31. Turnover more than halved from $510.9 million to $216.4 million and a dividend will not be paid as the directors believe it more prudent to conserve cash. Over the year, the company said it finalised licensing and design work on mainland projects in Nanjing and Qingdao and says its projects in Vietnam and North America are progressing well. A spokesman said: ''The group is in its second full year of operation as a property development company [and has] invested its cash resources in projects with maturities from two to six years.'' He said projects in Richmond in Canada, and Seattle in the US should be completed early next year. ''The group's Seattle project will be completed in the middle of next year. The group has a preferred equity and profit distribution right for this project and profits are expected to be booked in the 1994-95 fiscal year.''