In the liveaboard situation I was in, the guide already shot up the DSMB and we were on the surface. The problem was that we were in the wrong place and surfaced sooner than planned. The dive plan called for rounding a corner, into a bay, before surfacing. We encountered strong current at the corner, which quickly used up air, thus the earlier than planned surfacing. The guide waved the DSMB at the tenders, which we could see, but they obviously weren't looking for us yet. We tried whistles and DiveAlert. No luck. We tried my Nautilus Lifeline, which I hadn't charged fully, so the Chat function was disabled. In the end, we just had to wait until the tenders finally got off their break and start looking for us. We were the first dive group and pretty quickly, the other two dive groups surfaced around us. They encountered the same strong current, even some down current.