Strikes that are crippling the port of Piraeus in Greece last week and this week are just the latest in a series of industrial actions and other problems that are inflicting severe damage to the port.

Tugboat crews struck between last Friday and Sunday while an action by the Panhellenic Seamen’s Federation is still ongoing.

The tugboat strike stranded at least 15 large container ships. The seamen’s strike is expected to continue until at least Thursday night. Port workers struck for a month last spring.

Research indicates that Piraeus lost 15 working days in container handling this year due to strikes, but also problems with pilot boats and tugboats. The port has also lost 30 days for cruise tourism and two months of its railway link with Europe due to a blockade at Idomeni by refugees from Syria. Experts estimate that the port of Piraeus has lost 10 percent of its potential output in 2016.

As a result, the port has lost competitiveness compared to its Mediterranean cohorts. The Piraeus Port Authority has suffered a weakening in bargaining power with international container and car shipping companies and cruise operators.

The consistent inability of the pilot service to meet demand at the port could jeopardize the port authority’s negotiations with major shipping alliances to call on the port at all. Reports by local news agencies say that the shipping companies are complaining that the strikes and the pilotage delays are costing them money.

The government of Greece privatized the port of Piraeus, along with the port of Thessaloniki last year as part of a $96 billion bailout deal with the European Union. After some delay, the government sold its two-thirds interest in Piraeus to the Chinese carrier and port operator COSCO in a deal that closed last April. COSCO had earlier owned a minority interest in the port and had operated two of its three cargo piers.