Black Flags - Netting?

[L-Plate]

A few weeks ago, we were out off Eastern Moreton Island, heading out to Square Patch from the 35s. We haven't had heaps of experience outside so were motoring nicely along. We pulled up with a bit of a fright when a deckie noted a black flag bobbing around on a buoy to the North of us. We then noted another buoy with black flag further south of us. Essentially drawing an invisible line between the two and we were headed across that line. With little experience outside, we were very cautious when crossing this "invisible line" - I was worried that something below the surface would foul my prop. We didn't see anything. Can anyone give any advice as to what this may have been? It was on a Monday over Christmas break (gosh, that long ago!) and it was about 10.00am.

We had only just heard of the dive boat going down at Flinders after having fouled her anchor so we were quite concerned.:o

[lido76]

Mate the were probs pro spanner crabers wouldn't imagine that there would be any nets below.cheers brendan

[DALEPRICE]

gday mate,

brendan has hit the nail on the head with what they are, may also
have been the head and tail float of a set of sand crab gear. Most of the
crabbers run weighted ropes, though some dont and have 20 metres
of slack rope that sometimes floats behind the flag when its calm so it pays to keep a little bit away.

cheers dale