The primary judgment
31 Having considered all the documentary evidence and the evidence of the witnesses, the trial judge concluded on the balance of probabilities that:
(a) On 17 December 2001, the claimants' boat, while moored at Little Sirius Cove around lunchtime, starting taking in water at such a rate that the boat quickly sank.
(b) The water entered the boat via the starboard engine muffler which had partly come apart between the base or flange of the body of the muffler and the flange of the base of the muffler, both pieces having been joined by bonded fibreglass in the manufacturing process.
(c) The water entered the bonded flange of the muffler through a process called "wicking".
(d) The ingress of the water between the two "mating surfaces" had caused a "delamination" or debonding, in parts sufficient to allow the water to flood, notwithstanding the relatively low pressure at which the muffler operates.
(e) It is not clear whether the fibreglass bonding delaminated allowing the "wicking" of the water in the first instance, causing further delamination, or the wicking occurred first, causing the delamination by the egress of the water.
(f) Both the starboard and port mufflers (the latter did not leak and was in sound condition when inspected by Mr Box on 18 December 2001) were suspended by three hoses - two input hoses from the boat motor and one exhaust hose - such that the muffler body and base were suspended above, but not attached to, the hull of the boat, either by self-tapping screws or otherwise.
(g) The running of the motor caused the muffler to vibrate, but that vibration was not causative of the splitting of the starboard muffler base from its body that allowed water to being to "wick" its way between the mating surfaces.
I interpolate here that this finding ((g) above) has some significance for one of the two theories for the cause of the muffler failure, based not on poor fibreglass bonding at the flange, but on a theory advanced by Dr Scheirs, FM's expert, when cross-examined. He said it was due to loss of integrity and deterioration in a "gel coat", which he said was due to vibration, at least in part.
(h) The splitting of the base of the starboard muffler from the body was a gradual process that occurred between the muffler's installation by the second defendant, Mr Turner, two years previously and 17 December 2001, culminating in the division of the base and the body of the muffler on that day to such an extent that sea water was able to enter the bilge of the boat and ultimately sink it (judgment, WB, 26-27).
32 After making these findings, the trial judge emphasised that the claimants bore the onus (judgment, WB, 28) and that the evidence disclosed that no expert or the manufacturer could give a clear and unequivocal reason for the muffler's failure. The trial judge appeared to find significance in the fact that the port muffler, also manufactured by FM, was installed at the same time as the starboard muffler and in the same manner (supported only by three hoses), yet it did not fail. Indeed according to Mr Box it was intact with no leaking when he examined it (judgment, WB, 28).
33 The trial judge then commented that "the number of reasons or possible reasons advanced by the experts for the muffler's failure were considerable" and can be taken from the written submissions of Mr Turner as follows:
(a) The interface between the body and the base failed and was weak.
(b) Water came from the inside of the muffler to the outside.
(c) Water came from outside the leading edge of the muffler to the inside.
(d) Flexing of the flange.
(e) The form of construction (there being no fibres in parts going across the interface).
(f) Catastrophic event or number of small events.
(g) Poor adhesion.
(h) Overpressure.
(i) Inadequate construction/ poor manufacture.
(j) Loss of integrity/ deterioration of the gel coat.
(k) Backfire.
(l) Dropping a spanner on the edge of the muffler.
(m) Removal of the gel coat by being subject to chipping or stress or mechanical interference.
(n) Inadequate construction of the muffler at the base.
(o) Normal pressure resulted in delamination of the base (judgment WB, 28-29).
34 I interpolate here that the trial judge made no attempt to relate the various supposedly separate reasons for failure to either or both of the only two explanations for that failure. Nor did he group those supposedly separate reasons as they bore upon, or were elements of, the only two possible explanations. In determining the cause of the muffler's failure, not on the basis of a clear and unequivocal reason, but on the correct test of the balance of probabilities, that should have been done.
35 The trial judge dealt with the question of breach of duty on the premise that there was no doubt that the manufacturer FM owed the claimants a duty of care.
36 The trial judge discounted the evidence of Mr Box, who was a self-employed surveyor, assessor and insurance loss adjuster, a certified naval architect. Mr Box had identified the cause of the muffler's failure as a failure of design and manufacture by FM, rather than a problem with the installation. He discounted Mr Box and his conclusions on the basis that Mr Box had not explained how the design and manufacture of the muffler were inadequate or involved a defect. Neither did any of the other experts, according to the trial judge. Thus he concluded that there was no evidence of what FM could or should have reasonably done in the manufacture of the muffler to prevent the delamination at its base (judgment WB, 31).
37 The claimants tendered a report of Dr Graham Edward from the School of Physics and Materials Engineering, Monash University dated 7 October 2003, his expertise being in relation to polymers including polymer recycling and degradation. The trial judge however stated that he did not attribute "great weight" to the conclusions of Dr Edward as to the defects in the flange and its bonding because of his limited expertise. This was on the basis that Dr Edward had conceded in cross-examination that:
(i) His expertise was in polymers.
(ii) He was not familiar with the manner of constructing this type of muffler.
(iii) He was not given and did not seek any information about how the muffler was constructed, and
(iv) He could only "surmise" how the muffler was made (judgment WB, 32-33).
38 The trial judge concluded that without "convincing evidence" as to the actual defect in the design and manufacturing process and what could or should have been done to correct it, he could not find that FM breached its duty of care to the claimants (judgment WB, 33).
39 Although the claim in negligence against Mr Turner is now of no relevance to this appeal, certain findings remain of significance. The trial judge concluded that he was not convinced that Mr Gorman, a director of FM, whose evidence he had otherwise accepted, had given precise instructions to the second opponent, Mr Turner, to the effect that the muffler must be secured to the boat by a "four point fix" (judgment WB, 34). I interpolate a "four point fix" was by way of four bolts in the circumference of the flange whereby the body of the muffler is secured to its base via the flange.
40 Mr Gorman impressed the trial judge as a witness, particularly his belief in the integrity of his product (judgment WB, 34).
41 In any case the trial judge had regard to the fact that:
(a) Mr Box did not think that the four screws would have prevented the delamination,
(b) The muffler was secured by the three hoses, its own weight and its position in the boat, and
(c) Mr Box had experience of a muffler having delaminated in circumstances where it was secured (judgment WB, 34).
42 Thus while acknowledging that Mr Turner had a duty to the claimants to install a muffler in such a manner as to prevent damage, in light of that evidence, the trial judge was not convinced that this duty had been breached (judgment WB, 34).
43 I interpolate that this conclusion has implications for the second theory based on deterioration of the gel coat. Dr Scheirs gave evidence that wicking was the cause of the water entry causing in time delamination. His evidence was that this would have been made less likely by reinforcement around the base such as through fasteners or a circular clamp or thicker flange or additional matting (transcript WB, 167.20-168.32). His evidence on the use of screws was that it would have stopped the muffler deflecting under vibration and would ultimately have protected the gel coat from chipping so letting water in. The following passage reflects that conclusion:
"Q. So the screws would stop the deflection, is that what you are saying?
A. Yes.