Quoting an answer I gave to the same question asked here in another thread.
The feature of destroying other people\'s ships- be it by hand, in a salvage ship, or with weapons- is one of the best aspects the game can have.
It\'s not that hard to get away from this problem. If you sit around the spawn shop on a server (eg. like on NASS), you should not be surprised at all if you have people taking blocks off your ship. You\'re inviting them to do that by sitting around there. It\'s like on minecraft servers- Building your house close to the spawn area is a bad idea because it will get griefed by the one-timer trolls and rule-breakers. Likewise, don\'t make the unwise choice of building your ship at spawn. Just spawn yourself a ship core, get out to a safe place (several sectors away) and build it there.
Having the aspect of players sabotaging and eating away your build is one of the many dangers you face as a ship commander. Protect yourself. Arm your ship with the best weapons, construct it at your own secret base, or join a faction- that\'s where there\'s strength in numbers. Rather than trying to run away from the problem by complaining about it as a dissapointment and an annoyance, make the smart choice of not allowing such a situation to arise by staying alert of your surroundings and protecting yourself.
Save your blueprint to the catalog as you build (so if it does get destroyed/griefed/whatever you can just go and buy back the ship design from a shop; this is why griefing is not as much of a problem on StarMade as it is on Minecraft), and don\'t make the bad choice of constructing your ship in an area clustered with lots of players. Problem solved.
Hope this helps.