It is within the framework of the discipline called tort law that the rules of compensation for damages are to be found. The Swedish general tort law is subsidiary, which means that laws that in the light of the question at hand seam more adequate shall be applied instead of the ordinary tort law.
Within the framework of what is colloquially called maritime tort law ( sjöskaderätt ) , one may for example sort legal rules concerning compensation for damages occurred under transport, by escape of oil from ships or damages occurred by collision of ships.
There are differences between the ordinary material law of torts and the material law of maritime tort law. Insofar one argues that legal, formal, coherency is the proper yardstick of legal legitimacy either the ordinary tort law or the marine tort law has to be wrong. Of course, one could argue that the correct yardstick is consequential coherence and that only the result matters independent of what kind of instrument (the joint and several- or the pro rata liability) that is used.
Another argument would be that there are differences as well in theory as in practice, but that those differences are justified in the light of that the political motives may differ between those the systems of law. In other words: the political instruments are set to achieve different political goals.