As long as the statutory compulsion operates the person in charge of the ship is not the owner's servant, and the owner is therefore not responsible for his acts. Thus at common law the basis of the owner's immunity is the legal compulsion upon him If the owner or his agent, the master, should request or permit the pilot to continue in command of the ship beyond the time he is bound by law to permit him so to do, then the relation between the owner and pilot becomes at common law a contractual relation of service, to which the maxim of "respondeat superior" directly applies.
It is plain that the shipowner is liable for the negligence of a pilot voluntarily engaged because the relationship thus established is considered to be that of master and servant. This principle of the common law was considered in depth in a test case before the First Division of the Court of Session in 1925. The case was Thom v. J. & P. Hutchinson Ltd (Owners of S.S. "Smerdis") [16] . The widow and children of a ship's engineer sued the shipowner for damages in respect of the engineer's death, which was caused by the fault of a compulsory pilot. The claim was met by the defence of collaborateur, a Scottish doctrine which was equivalent to the English doctrine of common employment. By reason of s. 15 of the Pilotage Act 1913 U.K. - a provision in terms similar to s. 410B(2) of the Navigation Act 1912 Cth as amended, which I shall have occasion to consider later in these reasons - the owners of the "Smerdis" were to be answerable for any loss or damage caused by any fault of the navigation of the vessel in the same manner as they would be if pilotage were not compulsory. The pursuers maintained that the true relation between the owners and a voluntary pilot was that of agency and not of service, in which case the defence of collaborateur would have no place. The Lord President, in a judgment with which all three other members of the Court agreed, examined the submission in a passage which reads as follows [17] :
The point mainly relied on by the pursuers was the absence of power, on the part of the owners of the ship, to direct and control the manner in which the pilot exercised his duties. But if the employment is voluntary, I see no more reason to doubt the right of the employer to do so - however foolish it might be of him to attempt it - in the case of the pilot than in the case of the captain. It is, no doubt, true that the highly skilled nature of the work to be done and the remoteness of the ship from her owners make actual direction and control practically impossible in either case. But it is now for the first time suggested that the legal relation between a seaman and the owner of the vessel on which he serves is other than that of master and servant; and - though I rather think it is true that there is no case in which the true nature of the legal relation of a pilot (voluntarily engaged) to the owners has been canvassed - it has never been doubted throughout a long series of cases that it is that of service. The earliest quoted to us was that of The "Maria" per Dr. Lushington [18] . Lord Chelmsford evidently treated the point as one not open to doubt in Prowse v. European and American Steam Shipping Co. [19] , see at end of judgment. And the same understanding clearly underlies the reasoning in one of the latest cases (Steamship "Beechgrove" Co. v. Aktieselskabet "Fjord" [20] ). It is unnecessary to make a larger citation.
His Lordship concluded that "the liability artificially made to rest on the owners must be taken with all the legal qualifications attaching to it, and the defence of collaborateur is one of them" [21] .
1. (1839) 1 W.Rob. 95, at p. 99 [166 E.R. 508, at p. 510].
2. (1839) 1 W.Rob., at p. 103 [166 E.R., at pp. 511-512].
3. [1916] 1 A.C. 364, at pp. 382-383.
4. 1925 S.C. 386.
5. 1925 S.C., at pp. 392-393.
6. (1839) 1 W.Rob., at pp. 107, 108 [166 E.R., at p. 513].
7. (1860) 13 Moo. P.C. 484 [15 E.R. 182].
8. 1916 S.C. (H.L.) 1; [1916] 1 A.C. 364.
9. 1925 S.C., at p. 393.