Editing Ice (section)

===Water-borne travel===
[[File:Frozen Lake Huron- icebreakers and commercial vessels.jpg|thumb|Channel through ice for ship traffic on [[Lake Huron]] with [[ice breaker]]s in background]]
For ships, ice presents two distinct hazards. Firstly, spray and freezing rain can produce an ice build-up on the superstructure of a vessel sufficient to make it unstable, potentially to the point of [[capsizing]].<ref>{{cite journal |last1=Mintu |first1=Shafiul |last2=Molyneux |first2=David |date=15 August 2022 |title=Ice accretion for ships and offshore structures. Part 1 - State of the art review |journal=Ocean Engineering |volume=258 |doi=10.1016/j.oceaneng.2022.111501 |bibcode=2022OcEng.25811501M }}</ref> Earlier, crewmembers were regularly forced to manually hack off ice build-up. After 1980s, spraying de-icing chemicals or melting the ice through hot water/steam hoses became more common.<ref>{{cite journal |last1=Rashid |first1=Taimur |last2=Khawaja |first2=Hassan Abbas |last3=Edvardsen |first3=Kåre |date=17 August 2016 |title=Review of marine icing and anti-/de-icing systems |journal=Ocean Engineering |volume=15 |issue=2 |pages=79–87 |doi=10.1080/20464177.2016.1216734 |bibcode=2016JMEnT..15...79R }}</ref> Secondly, [[iceberg]]s&nbsp;– large masses of ice floating in water (typically created when glaciers reach the sea)&nbsp;– can be dangerous if struck by a ship when underway. Icebergs have been responsible for the sinking of many ships, the most famous being the [[RMS Titanic|''Titanic'']].<ref>{{cite book |last1=Halpern |first1=Samuel |last2=Weeks |first2=Charles |year=2011 |title=Report into the Loss of the SS ''Titanic'': A Centennial Reappraisal | editor-last = Halpern | editor-first = Samuel | publisher = The History Press | location = Stroud, UK | isbn = 978-0-7524-6210-3 }}</ref>

For [[harbor]]s near the [[geographical pole|pole]]s, being ice-free, ideally all year long, is an important advantage. Examples are [[Murmansk]] (Russia), [[Pechengsky District|Petsamo]] (Russia, formerly Finland), and [[Vardø (town)|Vardø]] (Norway). Harbors which are not ice-free are opened up using specialized vessels, called icebreakers.<ref name="Sahari2021">{{cite journal |last1=Sahari |first1=Aaro |last2=Matala |first2=Saara |date=9 December 2021 |title=Of a titan, winds and power: Transnational development of the icebreaker, 1890-1954 |journal=International Journal of Maritime History |volume=33 |issue=4 |pages=722–747 |doi=10.1177/08438714211062493 }}</ref> Icebreakers are also used to open routes through the sea ice for other vessels, as the only alternative is to find the openings called "[[polynya]]s" or "[[Lead (sea ice)|leads]]". A widespread production of icebreakers began during the 19th century. Earlier designs simply had reinforced [[Bow (watercraft)|bows]] in a spoon-like or diagonal shape to effectively crush the ice. Later designs attached a forward [[propeller]] underneath the protruding bow, as the typical rear propellers were incapable of effectively steering the ship through the ice <ref name="Sahari2021" />