Having lost a few fins to hitting wildlife and sandbanks in the past it was suggested to me by local sailor Steve to carry a Trolling Paravane
instead of swimming in, waiting for a tow or friggin' round tying your harness round the back of the board.
I had cause to use it today and was surprised how ridiculously simple and effective it was to use and you can stuff it in your pocket or vest and only $13 @ BCF
www.bcf.com.au/p/neptune-trolling-paravane/127060.html?gclid=EAIaIQobChMI9O7T4PHm3AIV1amWCh1orABMEAQYASABEgLZs_D_BwE&gclsrc=aw.ds

Wow what a great idea. Would never have thought of it.

A must for anyone sailing long distance or way offshore

^^ Just guessing, but ive used them fishing. Longer line allows paravane to dive deeper. At the cost of extra drag from the line which prevents it diving correctly. But we are talking 50m+ of line. Id think 1-2m should be ample to get home.

www.whitworths.com.au/burke-easy-stow-sea-anchor