This paper presents 2 sets of sea experiments on underwater acoustic sensor networks based on the TDA-MAC protocol that were carried out in May and June 2022 around the SEM-REV test field site. Since 2018 SEM-REV hosts the first offshore floating turbine prototype in France. A key conclusion from the sea trials is that the synchronisation between the assets must be carefully executed to succeed in the sensing data collection, especially in bad sea conditions. Packet Delivery Ratios (PDR) below 60% were observed, in particular, if no prior reliable handshake was recorded between the different assets. The paper lists several lessons learnt during those 2 sets of offshore experiments.