Tokyo Bay's signpost, the largest buoy in Japan, is removed/3rd Regional Coast Guard Headquarters

Translated from the original article at: http://news.kanaloco.jp/localnews/article/1202200001/


February 20, 2012

Japan's largest floating signpost (left) is removed and replaced with a new floating style lantern structure=Tokyo Bay

On the 19th, the 3rd Regional Coast Guard Headquarters removed the country's largest buoy (The Naka No D Floating Lamp Post) from the northernmost shallows of Tokyo Bay, replacing it with a new structure.

Raised from the sea's surface, the buoy measures at 10 meters high with a foundation diameter of 10 meters. Including the anchored weight at the bottom of the sea, it weighed in at 212 tons. It was set up in 1979.

The new lantern stands at 12 meters. Differing from the one before, it is not fixated by a long chain at the bottom of the ocean. Because of that, the chances of it waving about and drifting off are slim. It's said to be more effective as a route point for establishing width.

The floating style lanterns completely fit within the standards of the International Association of Marine Aids to Navigation and Lighthouse Authorities. The 3rd Regional Coast Guard Headquarters has been working to exchange buoys since 2003. There are 209 navigation markers within Tokyo Bay. The The Naka No D Floating Lamp Post is now the 81st marker to be switched to floating style lanterns.


Original text:
東京湾の道しるべ、国内最大のブイ撤去/第３管区海上保安本部
2012年2月20日

撤収された国内最大の灯浮標（左）と新設された浮体式灯標＝東京湾

第３管区海上保安本部は19日、東京湾の浅瀬北端の目印となる国内最大のブイ「中ノ瀬Ｄ灯浮標（とうふひょう）」を撤収し、浮体式灯標を設置した。

引き上げられた灯浮標は海面から高さ約10メートルで、土台部分の直径は約10メートル。海底に沈めた重りを含め総重量２１２トンで、１９７９年に設置された。

新設された灯標は海面から高さ約12メートルで、従来のものと異なり、重りに固定する際に長い鎖を使用しない。そのため、標識の振れ回りや流失事故の恐れが少なく、航路幅を有効に活用できるという。

浮体式灯標は国際航路標識協会の規格を満たしており、同保安本部は２００３年から交換工事を実施。東京湾内にある２０９基の航路標識のうち、今回の設置を含めて81基が浮体式に切り替わった。