depends upon the size of the chain: some chain is just as strong as any cable....but ANYTHING can be cut through if someone really wants to take your boat.....chains and cable are there to discourage "casual" thieves , or young kids looking for mischief or whatever: a serious thief will use a power tool to easily cut though any of those things. Same thing for the locks, again, discouragement. I have had locks that couldn't be opened anymore and I was able to cut through them in order to install the new lock. Make sure you report it to the proper authorities, especially, DEP, because since you are registered for that spot, you don't want to lose it, so that you can replace the stolen boat legally with DEP.