A superyacht owned by the Russian billionaire Alexei Mordashov was able to transit the blockaded strait of Hormuz after undergoing maintenance in Dubai because neither Iran nor the US objected, a source close to Mordashov said on Tuesday. It has been unclear how the multi-deck pleasure vessel, worth more than $500m (£370m), gained permission to sail on Saturday through the commercially important waterway at the heart of the US-Iran conflict, where traffic has been severely restricted since February. Alexei Mordashov. Photograph: Kommersant photo agency/Rex/Shutterstock Sailing under a Russian flag, the yacht, called Nord, crossed the strait on an approved route in compliance with international maritime law, the source said. “Iran did not interfere with the movement of the yacht, as it is a civilian vessel of a friendly country conducting a peaceful transit.…