Martyn has 42 years of international shipping experience and has worked for shipowners, operators and shipbrokers in London, Johannesburg, New York and now Singapore. The companies he has worked for include Van Ommeren UK, Simpson Spence and Young Johannesburg, Clipper Bulk USA and HSBC London. Martyn joined Grindrod Limited in 2008, was appointed Chief Executive Officer of its subsidiary Island View Shipping in 2010, and became Chief Executive Officer of Grindrod Limited's Shipping Division in 2011. He was appointed to the Grindrod Limited board in 2011 as an executive director where he served until the listing of the Shipping division on the NASDAQ in June 2018.
Martyn is a director of the UK Freight Demurrage & Defense Association (UK), a director of BIMCO representing Singapore, a member of the advisory panel to the Singapore Maritime Foundation and is a member of the Baltic Exchange, having been first elected in 1979.