If you're using a multiplier or centrepin then wind in the face can cause
your tackle to stop dead in the air while the drum continues to turn - cue
nest. If you 'snatch' the cast - too short an action this too can cause
underpower at the tip while spinning the reel up more than usual. Scraps
of
seaweed/debris catching briefly in the rings can slow the tackle without
slowing the reel and of course an underbraked reel (or not enough thumb)
allows the reel to turn for too long.

If you have a fixed spool then either it is overfilled (with springy,
heavier line the fill is more critical.) or again you have sticky
weed/debris causing coils to clump together - usually only a problem if
the
line is wound on under minimal tension.

Hmmmm...

Maybe you're getting line-twist and it's twizzling up in which case look
to
your swivels.

Hth. Cheerio,

Thanks, yes it does help; I don't use a centre pin or multiplier reel (and
since I didn't mention it at all, I'm not sure why the other poster seemed
to think I did use one - but thanks for the advice anyway Tetley!).

I reckon as I'm new to it all, I'm probably doing a few of the things you
mentioned all at once - slightly snatching, into a slight headwind, perhaps
with a bit of weed and swivel twisting going on.

I guess its not something you notice that frequently in your casting if
you're a sit and fish type of person (I like to move about a lot and so cast
more often and consequently experience more nests as I'm picking up the
knack of sea casting).

Cheers!