By Tanker Through Thick Ice
Sailing through 60 cm thick ice in minus 20 degrees is a extraordinary experience.
Thomas boarded the vessel outside Copenhagen. After sailing 1½ days, the vessel met the first ice at the entrance of the Finnish Gulf:
”You never know when you meet the edge of the ice because the wind plays an important role in the creation of the ”new ice”, which is the first sign of creation of ice. The surface of the water becomes almost oily and ice crystals are formed in the water. Shortly after, 70-80 per cent of the sea was covered by ice.
The captain looked almost as much behind as ahead of the vessel. He did so to see how quickly the ice closed behind the vessel to get an impression of the ice pressure. As long as there is more than 20-30 m open water behind the vessel, there is no reason for concern for an ice class 1B vessel as Baltic Wind. After less than half an hour, the sea was totally covered by ice, even if it was still relatively thin – between 5-20 cm. The speed was 11-12 knots.
Assisted Small Vessels
Already three hours later, when the vessel passed Tallinn, the ice was 20-30 cm thick, and we began to pass small vessels which were stuck in the ice. The captain told us that small vessels are often stuck in the ice for 4-5 days waiting for an icebreaker or a vessel passing sufficiently close to help them loose.
Within an hour, Baltic Wind had passed three vessels which all became able to continue and follow us, and we now formed a convoy, led by Baltic Wind. The speed was 8 knots.
Over the radio we heard that an oil tanker called for assistance from Admiral Makarov, one of the five ice-breakers which assist vessels bound for Russian ports. The ice-breaker would be on the spot within 2-3 hours.
Convoy Sailing
The captain decided to stop Baltic Wind and wait for the ice-breaker, even though our speed by that time was 6-8 knots. That was a wise decision. In the line of Admiral Makarov we were able to maintain a speed of 12-13 knots and simultaneously we spared the hull from the ice. Shortly before St. Petersburg, Makarov changed her course heading for Primorsk, and we had to continue alone through 50-60 cm thick ice – somewhat of an experience.
After three hours we had to surrender to the ice and could no longer proceed on our own. Four hours later, another vessel passed sufficiently close by to enable us to get free and sail to St. Petersburg Pilot Station. Here, more than 20 vessels were waiting for pilot and ice-breaker assistance. After a couple of hours, an ice-breaker arrived and all vessels formed one long convoy with Baltic Wind as number 9.
Helicopter Tugs
During the remaining part of the voyage to the port, the vessel was assisted by two so-called ”helicopter tugs”. They are called so, because they can turn around themselves in the water and simultaneously break the ice so the vessels can call at the harbour. The ice at the port of St. Petersburg is some of the hardest ice in the world due to the low contents of salt. Therefore, voyages in the Finnish Gulf and the Gulf of Bothnia are very difficult compared to e.g. arctic areas despite the greater thickness of the ice there.
The voyage gave me a good impression of the unusual conditions under which the ice tankers operate and many experiences that I will be able to make use of in my daily work”.
Worth knowing about ice
Thickness and consistency
New ice: The consistency of the water becomes almost oily and ice crystals are formed in the water.
Nilas ice: A thin elastic crust of ice, easily bending on waves (up to 10 cm).
Young ice: 10-30 cm thick ice. At this level, the ice will often “raft”; two ice flakes are pressed together, so one overrides the other. This doubles the thickness of the ice.
First-year ice: Ice formed during one winter with a thickness of more than 30 cm.
Old ice: Ice which has survived last summer. This ice is normally more “soft” than first-year ice.
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Concentration
The concentration of ice is normally measured on a scale from 1-10 determined by the share of the sea covered by ice:
Less than 1 (10 %): Open water
2-3: Very open drift
4-6: Open drift
7-8: Close pack
8-9: Very close pack
9+: Closed ice
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Ice Sailing
Sailing in ice, you sail slalom between the thick ice, trying to find the thinnest possible ice to gain as much momentum as possible and make as little damage to the vessel as possible. The darker the ice, the more fluid water it contains and the easier it is to pass through.
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