Fortescue Metals Group (FMG) founder and chairman Andrew Forrest has revealed an 8.1% stake in Australian shipbuilder Austal.

The mining and vessel chartering billionaire said in an Australian Securities Exchange filing that he has recently acquired 4.9% or 17.7m shares in the ropax specialist in an equity swap deal through his Tattarang Ventures company.

Tattarang has also acquired another 3.2% in Perth-based Austal in open-market share acquisitions.

Forrest’s total investments now stand at AUD 56.4m ($42.2m).

The deals could be seen as another demonstration of Forrest’s interest in zero-carbon shipping and shipbuilding.