About Diesel and Marine Group
Where it all started
The Simplex-Turbulo Group Ltd was first established in 1935 as a UK company selling marine components manufactured by Deutsche Werft (later Howaldstwerke-Deutsche Werft or HDW), a leading Hamburg-based shipyard.
Our first sale in September 1936 was for the rudder of the Castle Combe – it was so well balanced that, incredibly, no power steering was required.

Since then the business has developed into an international company supporting the marine and power generation industries, as well as other specialist industries with a range of high quality engineering equipment, in particular in:
the supply and service of sterntube seals and other ship’s components
the supply of spare parts for four-stroke medium speed engines
condition monitoring instruments including fuel test kits, particle counters, oil testing and vibration analysis
hydraulic oil surveys and oil purification/regeneration
Current ownership and directors
The company is still 25% owned by the original German founders (now SKF Marine GmbH, still based in Hamburg) with the remaining majority shareholding owned by the Hogg family, James (the Chairman) and Clare Hogg are active directors of the company, with Thomas Kaiser, of SKF Marine, also a board member.

James Hogg
James Hogg is Chairman of Diesel & Marine Group. He has an MA in Jurisprudence from Oxford University, and an MBA from London Business School. He has more than 40 years experience in the marine industry, 35 years of which has been with Simplex-Turbulo.

Clare Hogg
Clare Hogg is Director of Marketing and HR for Diesel & Marine Group. She is a language graduate; has a MA Marketing; is a Chartered Marketer; a Fellow of the Chartered Institute of Personnel and Development; and an Institute of Directors Accredited Director.

Thomas Kaiser
Thomas Kaiser is Director (representing the interests of SKF Marine GmbH) at Diesel & Marine Group. He has a M Eng Master of Engineering and has extensive experience in the marine and diesel engine industries.
These days Simplex-Turbulo Group Limited operates internationally, having registered companies in the UK, Germany and Singapore, and other offices in Spain (covering the Iberian peninsula) and Poland (coving the Baltic states as well as Poland). Of the 24 staff based at the headquarters in Hampshire, in the UK, a third are not British.
Companies included within the Group are Simplex-Turbulo Co Ltd, Lincoln Diesels Ltd, Simplex Converting Ltd (covering the converting industry) and STW GmbH. We also own the brand, Dorman Diesels.
What are our values?
We’re a family-owned company and we do our very best to try to ensure that all our staff feel respected and valued, and that they have a bit of fun along the way.

This approach also colours our approach to our customers. We build long-term relationships based on trust – we’ll give honest advice even if that means not making a sale!
That is also our approach to our suppliers, many of whom we have been working with for over forty years.
We’re all about quality. It’s an over-used word but we genuinely practice what we preach. We only source from manufacturers who also supply original equipment/engine builders. It’s just as important to us that the quality of our service is as good as the products we supply, our news feed is full of examples of customers who’ve been delighted and surprised by the lengths we go to in order to support them.
Solid and reliable
A1 credit rating
UK companies are ISO 9001 certified
£5m product liability insurance
A turnover of £14m in 2020; 60 employees and specialists