The appellant, De Beers Marine (Pty) Ltd (DBM), was the owner of an autonomous underwater vehicle (AUV), a robotic submarine which was used to map the seabed in its mining operations off the coast of Namibia. In September 2017, DBM concluded an agreement with the respondent, Harry Dilley (Pty) Ltd (HD), for the charter of a work boat to assist DBM in conducting sea trials in False Bay, Western Cape, to commission new equipment installed on the AUV. The work boat, the MV Nkwaza, was owned and skippered by Mr Harry Dilley, the sole director of HD.

During sea trials on 27 October 2017, the AUV suffered a communication breakdown and ended up washed ashore on the rocks near Simon's Town. The AUV was refloated and towed by the Nkwaza to Simon's Town harbour. HD subsequently instituted a salvage claim against DBM in the Western Cape Division of the High Court. The High Court held that HD was entitled to a salvage reward of ZAR 5,525,288.23. DBM appealed.

Held: The appeal succeeds in part. In terms of art 13.1 of the Salvage Convention 1989, in the Sch to the Wreck and Salvage Act 94 of 1996, a salvage reward of ZAR 80,000 plus interest is fixed.

There are two questions which this Court must consider. The first is whether the services by HD were rendered voluntarily or under contract. It is a settled principle that a claimant's entitlement to a salvage reward depends on whether it rendered the services in respect of which it claims 'voluntarily', ie without any pre-existing contractual or other legal duty. Although the Convention does not expressly include a general rule that in order to qualify for a salvage reward, a salvage operation must be voluntary, it does so by implication, by laying down general rules for the recovery of salvage and certain qualifications. The Convention restates the general principles of English common law that a salvor must be a volunteer to claim a reward. Article 17 provides:

No payment is due under the provisions of this Convention unless the services rendered exceed what can be reasonably considered as due performance of a contract entered into before the danger arose.

HD's services cannot 'be reasonably considered as due performance of a contract entered into before the danger arose', within the meaning of art 17 of the Convention. HD's services were rendered voluntarily: it was engaged in a salvage operation.

Article 12 of the Convention states that a salvage operation must have a useful result before there is a right to a reward. Article 13.1 sets out the criteria for fixing the reward. Prior to the Convention, the tribunal or court would consider the factors present in the case at hand, whereas the Convention prescribes in art 13.1 the criteria to be taken into account when fixing a salvage reward. The Court is required to analyse those criteria in the light of the facts to distil an appropriate award in money terms. The main criteria in the assessment of a salvage reward are the dangers to the property salved, the nature and burden of the services provided by the salvors, and the salved value, having regard to the policies of encouraging salvage and environmental services, and promoting the safety of human lives. The other criteria are effectively emanations of the main criteria.

Here, the whole salvage operation took about an hour. Its success was mainly due to the efforts of the divers. By contrast, the Nkwaza, which is not a dedicated salvage vessel, was not really imperilled, given the distance that it maintained from the coast at all times. The towage of the AUV was uneventful. It did not require any special or extraordinary nautical skill. The finding that the Nkwaza was exposed to a fair degree of danger is unsustainable on the evidence. The value of the Nkwaza was not high. HD is not a professional salvor, incurred no loss or additional expenses, and did not use any of its own salvage equipment in the operation. All the equipment used was supplied by the divers.

That leaves the salved value of the AUV. The High Court erred in rejecting the evidence concerning the salved value of the AUV. The Court could not attribute to the AUV a value of some ZAR 55 million based on its replacement value determined many years after it was built, because that was not the value of what was salved. Article 13.1.a of the Convention refers to the 'salved value of the vessel and other property'. That is the value of the AUV after it has been salved. It is not even its value before the mishap that led to it being salved. It is what survives after salvage that matters. If the property salvaged is worthless, there can be no reward. This Court is therefore at large to determine an appropriate reward in the light of the criteria in art 13.1.

The analysis of the art 13.1 criteria above shows that there was no risk or danger to the Nkwaza during the salvage operation, making it very nearly a question of towage. Although the AUV was not at risk of loss or destruction, there was valuable equipment on board which had been damaged. It was imperative that the AUV had to be recovered as soon as possible to prevent it from sustaining further damage. That would have happened had it not been recovered promptly.

The salved value of the AUV at the relevant time was ZAR 2,766,000, and on the evidence it was of strategic and operational importance to DBM. The salvage operation was successful and carried out promptly, not least because of HD's readiness to respond. Looking at the case objectively, a salvage reward of ZAR 80,000 is appropriate. On an overall application of the criteria, this reward is fair to both parties and gives effect to the principle that the salvee should pay for the benefit received; that the salvor should be rewarded for the service provided; and that the reward should reflect public policy. Public policy in the law of salvage is implemented in the practice of making awards on a generous scale, so as to encourage salvage services.