Shouting into the water helps a bit, but an extremely good plan is to tap two pieces of metal together e.g. your specs on a watch, the pin of your belt buckle on its buckle square, a shirt button on a watch or belt buckle.
Ukungxola emanzini kuyanceda kancinci, kodwa icebo elilungileyo kukubethanisa iintsimbi ezimbini kunye umzekelo iindondo zakho newotshi, unotaka webhanti lakho, uxakatha kulo, uxakathe nakwisikwere, iqhosha. Lehempe, kwiwotshi, okanye ibhanti exakathileyo.