英和和英

出典:『Wikipedia』 (2011/06/10 09:52 UTC 版)

英語による解説

引用

A caisson lock is a type of canal lock in which a narrowboat is enclosed in a sealed box and raised or lowered between two water levels. It was intended primarily as a water-saving measure, but also to save construction costs when compared with other engineering solutions. It was capable of replacing up to seven conventional locks.[[1]] Other design benefits were speed of boat decent /ascent, and only a little loss of water when operating compared with a conventional boat lock, which required a volume of water equal to a boat and its cargo weight for each lock used in a flight between levels.