Warsaw — The Soviet Union plans to strengthen commercial and Warsaw Pact communications on its northern flank with a major ferry project across the Baltic that links a Lithuanian port with a port on an East German island.
Construction of the new terminal has begun, as has the laying of the first hulls for the vessels that will operate it. The Soviets already have such a ferry link on the southern flank of their defense perimeter, crossing the Black Sea between the south Ukrainian port of Odessa and Varna, one of several big Bulgarian harbors.
The existing ferry and the projected one will have more in common than shipping and operational design. They will also have a potential significance in the event of war: Each bypasses an ally in whom the Soviets might have less than total confidence in an emergency.
The Odessa-Varna link passes within sight of but does not stop at the Romanian shore or Romania's major naval and commercial base, Constanta.
Romania has frequently nettled the Russians with its independent positions in foreign affairs. It is, for example, the only East-bloc state to maintain normal relations with Israel through the long Arab-Israeli conflict. It has grown more chummy with communist China since Peking's break with the USSR and the East bloc in the early '60s.
The new Baltic ferry is to start operating in 1985-86. A direct link between the Lithuanian port of Klaipeda (prewar Memel) and the East German port of Sassnitz on Rugen Island, it will bypass Polish ports like Gdansk and Gdynia.
The Poles have said little or nothing about the project, which was disclosed in the German communist press recently. But they suggest it will have no appreciable effect on Poland's earnings from transit traffic. It is said the need for the ferry arose principally because Soviet-East German trade has increased so fast - tripling in the last decade - that existing sea routes and Polish transit facilities are no longer adequate.
The reason for bypassing Poland is almost certainly the instability it has presented from a Warsaw Pact point of view ever since the summer of 1980. Earlier, during the 1976 strikes, workers from the Ursus tractor plant here cut the main international East-West European railroad. Ever since, the Soviets have worried that uncontrolled Polish unrest could threaten the all-important lines of communication to their forces in East Germany.
In July 1980 - in the first strikes before the great Baltic stoppage - Lublin railwaymen repeated the performance of blocking a main line to Russia, increasing Soviet apprehensions. This kind of threat has been high in their thinking ever since.
This concern outweighs any other about Poland, and any clearly perceived danger of this kind would be the one factor likely to prompt direct Soviet intervention.
Martial law provided some guarantee. But, since its partial removal in December, there have been periodic indications that Soviet anxiety about Poland's political and internal situation has not subsided.
The new ferry will apparently be similar to the Odessa-Varna line. The 300 -mile Baltic crossing will be maintained, on a daily 20-hour schedule, by six 560-foot vessels, each of nearly 12,000 dead weight tons. Three will be Soviet and three East German. Each will have a capacity for more than 100 freight cars together with trucks and merchandise.
The vessels will be fitted with Russian broad-gauge rail on two levels. In an emergency they, like those on the Odessa-Varna run, could easily be adapted for carrying military hardware and equipment.