The shipping casualties that hit the headlines are generally the major total losses, particularly those associated with serious environmental damage. However, the main call upon hull and machinery insurance policies come from partial losses, or 'particular average' claims, resulting from damage to vessesl and their machinery suffered due to the ordinary hazards of maritime trade. Once policy coverage has been determined, the crucial question is how much the policy pay. The insurer will be looking to see repairs carried out with all possible economy, whereas the assured, particuarly in the current buoyant freign markets, will want the vessel back in service as soon as possible. The Marine Insurance Act (MIA) 1906 states that the measure of indemnity is the 'reasonable cost of repairs' and this article examines how this phrase is interpreted in practice, in the context of policies subject to English law.