| 翻訳と辞書 |
| Otso (icebreaker) ： ウィキペディア英語版 |
Otso (icebreaker)
''Otso'' is a Finnish state-owned icebreaker. Built by Wärtsilä Helsinki shipyard in 1986 to replace the aging ''Karhu''-class icebreakers, she was the first Finnish post-war icebreaker to be built without bow propellers. ''Otso'' has an identical sister ship, ''Kontio'', which was delivered in 1987.
== Development and construction ==
In the early 1980s, the Finnish National Board of Navigation began looking for a replacement for the aging ''Karhu''-class icebreakers ''Karhu'', ''Murtaja'' and ''Sampo'' which had been built in the late 1950s and were no longer wide enough to escort modern merchant ships.〔Karhu II - A new-generation icebreaker. Shipping World & Shipbuilder, October 1985.〕 Furthermore, the old icebreakers were expensive to operate and, despite their small size, required a relatively large crew of 53.〔Kaukiainen (1992), page 330.〕 The development of the new class of icebreakers, dubbed ''Karhu II'' in the preliminary papers, intensified when Wärtsilä opened a new ice model test facility in 1983. The tenth post-war icebreaker of Finland was ordered from Wärtsilä Helsinki shipyard on 19 March 1984 with a price of FIM 235 million.〔〔Uusi murtaja tilattu. Suomen Merenkulku 6/1984. Page 43.〕 The ship was launched on 12 July 1985 and delivered to the owners on 30 January 1986.〔Helsingin Sanomat, 31 January 1986.〕 Her name, ''Otso'', is one of the many epithets for bear in the Finnish language. In January 1987, ''Otso'' was followed by a similarly-named sister ship, ''Kontio'', after which the three ''Karhu'' class icebreakers were decommissioned and sold.〔
During extensive ice trials in the Bothnian Bay in March 1986, ''Otso'' was put through a series of test to determine her icebreaking capability. In a race against the 1975-built ''Urho'' in level ice, ''Otso'' beat the older but more powerful four-propelled icebreaker by a ship's length,〔Turunen (2011), pages 37–39.〕 showing that in terms of ice resistance the new icebreaker was superior to her predecessor.〔〔 In ice, she could easily maintain a speed of and small ice ridges along the way appeared to be of no consequence to the vessel. However, the strength of the new icebreaker was put to the ultimate test when she encountered a large pressure ridge reaching all the way to the seafloor some below the surface. After preparations, ''Otso'' was accelerated to a speed of and rammed into the ridge at full power. Since the new icebreaker had a smooth inclined stem and lacked the bow propellers of her predecessors, she rode up the ridge and began listing to the port side as the hull rose from the water. After coming to a stop, ''Otso'' slid back by herself without utilizing the engines, and the ridge was penetrated on the second charge.〔〔 The robustness of the ship and its propulsion system were further proven when the icebreaker was backed into a ridge at "to prove to the customer it doesn't break".〔(Icebreakers! ) Popular Mechanics, February 1989. 〕
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Otso (icebreaker)」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|