The English aircraft engineer and boating enthusiast Tom Murrant (1939–2005) founded the Sealine parent company Fibrasonic Marine Ltd. in 1972 with the help of three other persons.

In the wake of the world oil crisis 1973, the young company suffered and survived several years by producing items for other sectors and as subcontractor for other boat builders.

[2] In the 1990s, Sealine entered the US-market and rose to one of the "Big Four" British motorboat builders (alongside Fairline, Sunseeker and Princess).

Tom Murrant and his Co-partners sold the company for US$45 million to a group of venture capitalists headed by the English industrialist Gerard Wainwright who started to improve build-quality and design.

[3] The new owner implemented advanced manufacturing structures, widened the range upwards and tried to attract the market with luxury.

In 2011, Brunswick sold the company to US-based private equity firm Oxford Investment Group.