A sudden patch of thick Lake Michigan ice and a missed radio call contributed to the Jan. 5, 2014, collision of a bulk carrier and a Coast Guard cutter.

The bulk carrier Mesabi Miner struck a glancing blow at two knots into the stern of the Coast Guard cutter Hollyhock, according to a new National Transportation Safety Board report.

Hollyhock was leading a convoy of six vessels west of the Straits of Mackinac in the late morning, in good conditions with visibility around nine miles in 12-degree air and 12-knot northwest winds. Behind the 6,200-hp, 2,000-GT, 225’x46’x13’ Hollyhock was the 16,000-hp, 1004’x102’x29’, 34,728-GT Mesabi Miner, carrying 49,000 tons of taconite ore pellets from Minnesota bound for the U.S. Steel dock at Gary, Ind. The bulk carrier, owned by Interlake Steamship Co., is capable of carrying 63,300 GT of iron ore in seven holds. 

After freeing several ships beset by ice, the cutter’s officer of the deck instructed the bridge crews by radio that he intended to lead the convoy westward at eight to 10 knots, and that the first vessel in line should maintain a distance about 1,000 yards astern of Hollyhock. After getting up to speed, the master on Mesabi Miner used throttles on the bulk carrier’s twin engines to maintain a distance between 800 yards and 1,200 yards, with a speed estimated at 6.5 knots to eight knots, according to the NTSB report.

“During interviews, both the commanding officer of the Hollyhock and the master of the Mesabi Miner described a fluid operation demanding close cooperation between the vessel operators in coordinating speeds and distances,” NTSB report authors wrote. “Both felt comfortable with the scenario that day and agreed nothing seemed out of the ordinary or extreme about the day’s icebreaking operations.”

At 10:39 a.m. the cutter encountered heavy ice, and the officer of the deck contacted the master on Mesabi Miner, who put both throttles in neutral with 959 yards between the vessels. At full throttle, Hollyhock went into the ice at 5.5 knots but came to a complete stop. The officer radioed a warning to the bulk carrier but did not recall hearing an immediate acknowledgement, the NTSB report said.

The third officer on Mesabi Miner saw the cutter was making no progress, and alerted the master who put both engines in full reverse. The ship was still making over eight knots with a distance of 821 yards. On the cutter, the commanding officer assumed the bridge and ordered the crew to back up and run into the ice at full throttle, to no avail.

He ordered full left rudder and sounded the collision alarm in an effort to get off the port side of the looming bulk carrier, and about 15 seconds later the bow of Mesabi Miner made contact with Hollyhock’s stern at about two knots.

The cutter was out of action for several weeks while $244,145 in estimated damages were repaired, including structural framing at the stern and port quarter in the steering gear room, aft laundry, the sternthruster space, fantail, railing, and two small hull punctures about 20 feet above the waterline.

The bulk carrier had estimated damage of $250,000 including inset of the hull plate at the bow, distortion of internal framing in the forepeak, and minor buckling of the main deck forward. The hull had a 12-inch crack about four feet above the waterline.

NTSB investigators concluded that the bridge crews of both vessels failed to adequately communicate before the collision, and that missed radio calls were a contributing factor.

“A procedure calling for confirmation and acknowledgement of radio calls during icebreaking operations could have improved the effectiveness of communications among all vessels in the convoy, particularly when standard minimum distances could not be maintained due to the nature of the icebreaking,” the report said.