[Mowgli]

Hey Kristian..

First and foremost, read both advises above over and over again.. They'll save your life..

In the abscence or presence of a free diving partner, you can also do it the traditional way the divers in the Gulf did decades ago..

Tie a rope around your waste and the other end either on the boat or in someone's hands who's on the boat..

If you experience SWB, you'll live..

If you don't have a dive watch to tell you your depth, you'll know..