Complex sentence: Surcouf had an altercation with Decaen but had to renounce his ship, and eventually purchased the "Sémillante", which he renamed "Charles", to return to Saint-Malo, where he arrived on 4 February 1809.
Split into simpler sentences: Surcouf had an altercation with Decaen but had to renounce his ship. Returning with this vessel to Saint-Malo, he arrived on 4 February 1809.