Total provisions made against the legal actions, which are widely believed to have been instrumental in the ousting of Richard Fulford-Smith as chief executive, now total ?27m.
Clarkson said the parties had agreed that the settlement’s terms would remain “confidential.”
The legal actions against subsidiary H Clarkson & Co concerned third-party commissions, which it is alleged to have improperly paid on business transacted during 2001-2004.
Sovcomflot and Novoship were claiming $67m.
Clarkson chairman Tim Harris said that after taking “detailed professional advice it was thought better to settle than drag on with expensive litigation, the outcome of which is always uncertain.”
Mr Harris confirmed that the settlement also covered another potential claim by Sovcomflot for $71m relating to “a routine year-end valuation”.
No provisions have previously been announced against this potential claim.
In last year’s accounts Clarkson absorbed legal costs of ?3.2m relating to the claims and, with a further six months of charges, this is likely to have risen to nearer ?5m.
Mr Harris said: “The Clarkson team, under [new chief executive] Andi Case, can now put all its energy and expertise into what it does best — and in so doing, take this company on to even greater success.”
He did not think the Russian disputes had damaged the group’s reputation.
“I believe this has been handled very professionally and we have been meticulous with the information given to the market,” he said.