The Coast Guard is your ally, along with the Navy. Talk to your insurance company; they have lots of experience (or else you picked the wrong one.)
Oh, are you equating copyright violation with major theft, murder and associated felonies so heinous that there is actually a separate body of international law to address it? Please don't do that.
Unless you are already a market leader, copyright violation is largely equivalent to an unpaid, unauthorized marketing issue. Your problem is to convert those non-paying users into paying users.
Policy:
1. Make it so inconvenient to use your software without paying for it that they decide to pay you. This is the "stick" option: you hit them with a stick until they either go away or pay.
2. Make it so easy and useful to pay for your software that they decide to pay you. This is the "carrot" option: you dangle something good in front of them until they willingly walk towards it.
Every method falls into one of those two policy groups. Think about which policy you want to use before you start making changes.
If you decide to make your software open source, you are likely to stop making money at it by selling it. However,
you can still make money by consulting -- you are the world's foremost expert on this software, after all.