3.2 Limitation and the basis of liability
MC §§ 172 and 172a only defines and delimits the groups of claims which are subject to limitation according to each of the two limitation regimes. These provisions are subject to the general rule that “shipowners”, as defined in MC § 171 (Article 1, paragraph (1) to (3) of the Convention), are entitled to “limit their liability” for maritime claims (supra 2.4.1). However, neither MC §§ 172 or 172a, nor the legal framework of the two limitation regimes, determines whether one or more of the persons entitled to invoke limitation, actually has personal liability for the particular limitable claims asserted. In general, the answers to such questions depend on the applicable rules of the law of damages. Both MC §§ 172 and 172a provide – consistent with the Convention Article 2 paragraph 1 – that the types of claims listed are subject to limitation, whatever the basis of liability may be. Even if invoking limitation does not mean admission of liability (Article 1, paragraph 7 of the Convention), there is a remaining problem that the actual basis of liability may differ both with the particular claim(s) asserted and with the person actually invoking limitation.
The “basis” for personal liability of the owner and/or the operator of a ship, however, may be different and vary with the particular claim(s) subject to limitation. The actual operator of the ship is generally liable according to MC § 151 for damage linked to the operation of the ship, while the removal and cleanup operations after a casualty to the ship is generally a strict liability imposed on the owner of the ship (infra 3.4.3). Hence, by determining whether or not the owner or the actual operator may be held personally liable for the particular claim asserted, the actual “basis of liability” may also be of consequence for the scope of application of either of the treaty-based or the national limitation regimes, as defined in MC §§ 172 and 172a. Thus, a shipowner, being not also the operator of the ship, may not be held liable according to MC § 151 for a claim covered by MC § 172, while an operator not being the shipowner, may not be liable for claims listed in MC § 172a (infra 3.4.3). If, in a particular case, the same person may be held personally liable both for § 172-claim(s) and for § 172a-claim(s), in the context of limitation it is nevertheless necessary to keep the two groups of claim(s) separate, because one group is subject to the limit in MC § 175, paragraph (3) and the other subject to the limit in MC § 175a. Additional questions relating to the basis of liability for particular claims are likely to arise if a casualty involves more than one ship (infra 3.4.6).
Accordingly, a maritime claim listed in MC § 172 or MC § 172a is not subject to limitation unless – according to applicable rules relating to the basis of liability – the shipowner or the operator of the ship actually invoking limitation is or may ultimately be held personally liable for the claim(s) asserted. In general, however, limitation of liability for claims covered either by MC § 172 or by MC § 172a may be invoked by the shipowner or the actual operator, if alleged by legal action to be liable for any limitable claim(s), cf. the rules on aggregation of claims in MC § 175, paragraph (4) and § 175a, second paragraph. The direct link between personal liability and the right to limitation is particularly apparent in Article 1, paragraph 1 of the Convention and in MC § 171 first paragraph. This also explains why § 171 first paragraph expressly refers to both of the two different rules relating to liability for claims in respect of the cost of loss-prevention measures now set out in § 172 first paragraph (4) and in § 172a, first paragraph (3) supplemented by § 179 (supra 2.4.3 at note 34).