Accountant, Simon Johns, 39, and James Coquelin, 38, who works for HSBC, bettered the previous mark of 343,285metres in the lightweight category of the 30-39 years age group on the Concept-2 rowing machine with a distance of 350,342 metres.
They were rowing to raise money for The Ivy Trust and The Priaulx Premature Baby Foundation charities and are confident of reaching their target of £7,500.
Donations can be made at www.justgiving.com/Row-24