Estonian shipyard BLRT Grupp is to modernise six Spliethoff MPPs.

The vessels are F-type units of up to 12,500 dwt, the yard said.

The deal includes installation of exhaust scrubbers and ballast water treatment systems.

BLRT had earlier won a contract for similar work on 14 of the owner's S–type ships with capacity up to 21,500 dwt.

"Work on modernisation of ships has already begun and will continue until the beginning of 2020," said Andrejus Babachinas, chairman of the council of directors of BLRT Repair Yards.