Cho Yang America, DSR-Senator Line and Hanjin Shipping Co. are looking to add up to 100 ships to the worldwide container fleet, a move analysts say will contribute to a severe surplus of container space.

The lines - known collectively as the Tricon group - have not announced how many ships they are building. But industry estimates go as high as 100, with each of the vessels being able to carry the equivalent of 4,000 20-foot boxes (TEUs) or more, replacing ships that can now carry up to 2,700 TEUs."It's still all being hammered out," said Paul Laign, general manager of operations for Hanjin. "We won't be releasing the details until December."

Tricon's ships will join a fleet of larger containerships that are on order and will come into the trades within the next two years. Some industry analysts say there could be more space than cargo to fill it.

"The possibility of overcapacity warrants some consideration," said Jim Lawrence, president of International Market Strategies.

Peter Shaerf, managing partner of the Commonwealth Group, said the lines ''could be heading toward maxing on capacity." Overcapacity traditionally has led to rate wars as the lines struggle to fill ships.

According to the magazine Fairplay, there are about 377 containerships on order. Many top the 4,000 TEU mark. South Korea's Hyundai Merchant Marine, for example, has orders for seven containerships capable of carrying up to the equivalent of 5,551 TEUs, about the same size as new ships for Maersk Line being built in Denmark.

Initially, Hyundai ordered only six ships that could carry up to 5,046 TEUs. Five of the ships are slated for the route between the United States and Asia, and the other two are slated for the Europe-to-Asia route.

China Ocean Shipping Co. has placed orders for six ships on the trans- Pacific route, each capable of carrying up to 5,250 TEUs.

As of early 1993, about 1,020 containerships plowed the trade lanes, having enough space for about 1.8 million TEUs. A survey by Fairplay in March 1993 found companies had placed orders for 219 vessels for delivery between 1993 and 1996. The combined capacity for those new ships is 746,800 TEUs.

Many of those vessels will replace smaller ships. According to analysts and ocean carriers, many of the bigger ships will call at a limited number of large hub ports. The smaller ships will be scrapped or used as feeder vessels in trades like Asia and South or Central America.

"Many of the lines are going into the hub-and-spoke principle," said Mr. Shaerf.

"We'll be putting the older ships in the north-south trade," said Conrad Everhard, chairman of Cho Yang America.

Other forces are pushing the shipbuilding. Some lines are doing it because other carriers are, Mr. Shaerf said. "Once the competition starts to build bigger ships, then you have to build the bigger ships."

Mr. Everhard said, "Everybody's building ships now. You've got to, if you want to stay in the game."

For some foreign companies connected to their governments or government- controlled shipyards, money is less of an obstacle.

"I understand that some of the Korean lines can effectively get 100 percent financing," Mr. Lawrence said.

Still, if bigger ships open up too much space for the market, all lines will suffer.

"The lines feel that they will have enough cargo to fill the space," Mr. Shaerf said. "These ships run about $80 million each. I don't think that's done without any planning."

Many of the lines will scrap more of their smaller, older ships, Mr. Shaerf said.

Other analysts said the reunification of Korea and opening of other markets in Asia will put even more cargo in world trade.

"Container shipping is still a maturing market," Mr. Shaerf said. "It's still only a developing market."