Scattered on this record is the factual debris that remains when, unfortunately, two ships do not pass silently in the night. The collision on December 16, 1962, between the SS Atlantic Sun and the SS Esso New York, both loaded tankers, resulted in the filing of claims by the owners of both vessels. Following an extended trial, the district court determined that the Sun 'did all that could reasonably and prudently be done, under the circumstances, to avoid the collision,' and granted Sun Oil Company exoneration from liability. The Esso was held solely responsible and Humble Oil and Refining Company was assessed damages in the amount of $407,093.55. This appeal followed.

On the morning of the collision, the Sun was bound for the open sea, leaving the Delaware River channel and proceeding down the Delaware Bay on a constant course of 157 degrees. The inbound Esso was proceeding up the Bay at a course varying between 350 degrees and 003 degrees, having navigated on the west side of the river channel opening in order to take aboard a river pilot at Lewes, Delaware. At approximately 0901, when the vessels were roughly three miles apart, the Sun detected the Esso on her radar. Her master concluded that the ships would pass safely starboard-to-starboard if the Sun maintained the 157 degrees bearing. There was logic to the expectation of starboard-to-starboard passing: Sun was on a southeastward heading; Esso was coming from the west shore and was proceeding northwardly, making for the channel entrance.

By 0906 the vessels had closed to approximately one mile of each other. Radar observations by the Sun confirmed her earlier belief in the safety of a starboard-to-starboard passing, and subsequent visual sightings allegedly substantiated this belief. At 0906.2, however, the Esso began moving east of 360 degrees, a movement presumably designed to emphasize the pilot's belief that a port-to-port passing should be executed. This gradual shifting of course was observed by the Sun.

At 0907, the master of the Sun, deciding that a safe starboard-to-starboard passing was no longer possible due to the Esso's change of course, ordered a 10 degrees right rudder in order to execute a port-to-port passing. Ten seconds later a 20 degrees right rudder was ordered. Before these course changes were seen by those on the bridge of the Esso, however, the Esso, at 0907.2 or .3, began to check its right swing and come slowly left. By 0907.5, before Esso's right swing was entirely checked, it had reached a bearing of 010 degrees which was perceptible to the Sun. Within the next thirty seconds the Esso's left rudder brought her to 008.4 degrees but this 1.6 degrees course change was not discernible to the Sun.

By 0908, therefore, the inbound Esso with engines full ahead was swinging left at 14.2 knots. The outbound Sun was swinging right at 11.7 knots, having moved 14 degrees from its 157 degrees bearing to 171 degrees. At this time the Sun went hard right rudder and the Esso began hard left, and both vessels were in extremis and on a collision course. Approximately one minute later the Sun sounded her danger signal and ordered her engines full astern. Just prior to the collision the Esso also ordered her engines reversed, but even the prompt execution of the order was unavailing. At 0909.5 the vessels collided.

Sun Oil contends that prior to 0906.2 when the Esso commenced a 10 degrees right swing, the Sun's master correctly concluded that the ships could have passed safely starboard-to-starboard; that the Sun's course change to the right was necessitated by the Esso's improper change of course from 360 degrees to 010 degrees; that even after Esso's right rudder the Sun's right rudder created a safe port-to-port passing situation; and that Esso's final hard left constituted the sole proximate cause of the collision.

Humble Oil argues that a safe starboard-to-starboard passing was never possible without earlier course changes. It insists that proper seamanship required the Sun to establish a port-to-port passing and to direct her course to Esso's stern; that the Esso's course change from 360 degrees to 010 degrees was justified as an attempt to create the correct passing pattern; that its subsequent hard left was executed not at 0908, but at 0907.3 before any perceptible course change by the Sun; and that this maneuver, putting the Esso in extremis, rendered any subsequent evasive tactics impossible. Humble concludes, more from dedicated advocacy than persuasive logic, that the sole cause of the collision was the Sun's failure to stay clear as required by the Inland Rules of the Road, Art. 19, 33 U.S.C. 204, thus creating a situation in which each vessel found it necessary simultaneously to guess at the other's intentions. Alternatively, Humble urges that, assuming its negligence, the like negligence of Sun in the failure to change course earlier should have precluded Sun's right to recover.

Filing extensive Findings of Fact, a Discussion and Conclusions of Law, the district court resolved all critical doubts in favor of the Sun. It found that when the Sun first sighted the Esso on her radar at 0901 her master correctly concluded that there would be a safe starboard-to-starboard passing. It also found that the Sun's 10 degrees and 20 degrees right rudders (at 0907 and 0907.17) were necessitated by the Esso's swing to the right which began at 0906.2, and that had these respective courses been maintained the vessels would have been cleared for a port-to-port crossing at a distance of approximately 1500 feet.

It was determined that the Sun was at all material times proceeding 'at a prudent and moderate rate of speed,' and that the Esso's engines were full ahead and accelerating after picking up the pilot. The district court further found that Esso began her hard left rudder at 0908, that by this time the Sun had come 14 degrees to her right, from 157 degrees to 171 degrees, that this course change should have been observed by the Esso, and that the Esso should have and could have done precisely the opposite of what she did do: she should have executed a hard right rather than a hard left. In the words of the district court, 'the sole substantial cause of the collision was the Esso New York's left rudder when the vessels were clear for a safe port-to-port passing.' As noted, the Sun was held blameless.

We have engaged in a painstaking review of the record in this case. Had we presided at the trial of this cause it is possible that the complex factual array would have led us to a different result. But in our role as an appellate tribunal, we are unable to say that the essential findings of the district court on the negligence of the Esso and the exoneration of the Sun were 'clearly erroneous.' Rule 52(a), Fed.R.Civ.Proc. Although the evidence was not uncontradicted, it was sufficient to support the trial court's findings.

This court has carefully defined our role as an appellate court in reviewing factual findings of a trial court. In Speyer v. Humble Oil and Refining Co., 403 F.2d 766, 770 (3 Cir. 1968) we said:

In reviewing the decision of the District Court, our responsibility is not to substitute findings we could have made had we been the fact-finding tribunal; our sole function is to review the record to determine whether the findings of the District Court were clearly erroneous, i.e., whether we are 'left with a definite and firm conviction that a mistake has been committed.'

This is consistent with the governing principles enunciated by the Supreme Court:

While, of course, it would be our duty to correct clear error, even in the findings of fact, (plaintiff) has failed to establish any greater grievance here than it might have in any case where the evidence would support a conclusion either way but where the trial court has decided it to weigh more heavily for the defendants. Such a choice between two permissible views of the weight of the evidence is not 'clearly erroneous.'

United States v. Yellow Cab Co., 338 U.S. 338, 342, 70 S. Ct. 177, 179, 94 L. Ed. 150 (1949). And to the same effect is Mr. Justice Douglas' statement in United States v. National Ass'n of Real Estate Bds., 339 U.S. 485, 495-496, 70 S. Ct. 711, 717, 94 L. Ed. 1007 (1950):

It is not enough that we might give the facts another construction, resolve the ambiguities differently, and find a more sinister cast to actions which the District Court apparently deemed innocent. We are not given those choices, because our mandate is not to set aside findings of fact 'unless clearly erroneous.'

Finally, we find no error in the allowance of damages for the expenses incurred in diverting another vessel to transport Sun's cargo to its destination, or in the award of interest-- conceded by Humble to be discretionary-- from the date of the collision. See, e.g., Rugo Constr. Co. v. New England Foundation Co., 172 F.2d 964, 967-968 (1 Cir. 1949); O'Brien Bros. v. The Helen B. Moran, 160 F.2d 502, 506 (2 Cir. 1947).

The judgment of the district court will be affirmed.

On this record Judge SEITZ cannot accept as many of the findings and conclusions of the district court as does the majority. However, he concurs in the affirmance of the judgment below because there is a sufficient evidentiary basis for the conclusion of the district court that Esso's negligence was the sole proximate cause of the collision.