Good question. If someone could invent something that stopped the little blighters eating the bait they be would become wealthy. On a serious note , crabs nicking bait it just one of those things. Sorry i can't be of any more help
Seriously the existence of crabs could be important if you're using crab bait as crabs equal FISH!
If the sea is still with little or no tidal current I sometimes fix a large float to the top of my trace which will keep the trace vertical lifting the top hook away from marauding crabs. However hungry crabs will shin up the trace! It does delay the litttle bu**ers! The rig is also very un-aerodynamic when casting.
As usual Swellys' right crabs should = fish. in my experience (admittedly limited) if you use crab as bait it tends to slow the little sods down quite a bit as opposed to using something like worm don't know why I don't suppose it's down to squeamishness on their part
ive found that using peelers does seem to stop them dead, perhaps they see themselves whipped on there??? also when being bothered by crabs, i put on 2lug, whip them right down and tip off with a bit of mackeral, that will solw them down, as it is just a bigger mouthful. if you are a flattie fanatic, (c'mon, no shame, admit it!!!) then having your bait floating above the seabed could be detremential to your fishing, but i find, getting a few lug, compacting them and whipping down tight, then tipped with a firm fleshed fish, mackeral etc, will slow them down a while, but being compacted, most species can get it in their mouths.
If you're getting bothered by crabs it means that you're in the right area for fish as fish will come in to eat the crabs or to feed on whatever the crabs are eating, which with a little bit of luck will be your bait
Another method you could try is to make your snoods using braid. I find this takes them a lot longer to nip through.
You could also try shortening the time that your bait is in the water. Start with, maybe 15 mins and then check your bait. If it has been savaged then try 10 mins etc. Some people may not agree with this but if the crabs have got there first and snaffled the bait, then no matter how long you leave your rig in the water, you wont catch a fish.
if you could fill a ragworm with C4,,have some sort of battery operated fuse that runs down the line from a little switch or button on the side of your reel..
when u see that familier crab pull on your line from ole Dave the crab..BOOOOOOOOOOOM!..then all his mates looking on,will see dave the crabs entrails floating around and will think, Sod this! im off!,
Therefore securing your next cast to be relatively crab free..and by blowing dave the crab to simtherines,,you have also made a nice ground bait to attract the much sort after Cod or Bass..
I smell a patent in the air chaps....im gonna be rich