船舶基礎(chu)知識：造船業(ye)的(de)噸位和排(pai)水量

為表示(shi)(shi)船舶(bo)的大小，除用(yong)(yong)船長(chang)、船寬等尺(chi)度以(yi)外，通常用(yong)(yong)噸(dun)(dun)(dun)位。船舶(bo)噸(dun)(dun)(dun)位種類繁雜(za)又易混(hun)淆，主要有四(si)種：①表示(shi)(shi)船舶(bo)的重量(liang)(liang)(liang)，排水量(liang)(liang)(liang)噸(dun)(dun)(dun)；②表示(shi)(shi)船舶(bo)的容積，用(yong)(yong)總噸(dun)(dun)(dun)（GT）或(huo)凈噸(dun)(dun)(dun)（NT）表示(shi)(shi)；③表示(shi)(shi)裝載貨物的重量(liang)(liang)(liang)，用(yong)(yong)載重噸(dun)(dun)(dun)（DWT）表示(shi)(shi)；④表示(shi)(shi)船舶(bo)建造工作量(liang)(liang)(liang)，用(yong)(yong)修正總噸(dun)(dun)(dun)（CGT）表示(shi)(shi)。

排(pai)(pai)水量(liang)(liang)(liang)噸(dun)(dun)：船(chuan)(chuan)舶(bo)(bo)(bo)浮在(zai)(zai)水面(mian)上時(shi)，排(pai)(pai)開水的(de)重(zhong)(zhong)量(liang)(liang)(liang)等(deng)于(yu)浮力，也(ye)等(deng)于(yu)船(chuan)(chuan)舶(bo)(bo)(bo)本身(shen)的(de)重(zhong)(zhong)量(liang)(liang)(liang)。因此，排(pai)(pai)水量(liang)(liang)(liang)噸(dun)(dun)也(ye)就等(deng)于(yu)船(chuan)(chuan)舶(bo)(bo)(bo)的(de)重(zhong)(zhong)量(liang)(liang)(liang)。排(pai)(pai)水量(liang)(liang)(liang)噸(dun)(dun)在(zai)(zai)軍(jun)用(yong)艦艇上廣泛應用(yong)，但在(zai)(zai)民(min)船(chuan)(chuan)上除待拆船(chuan)(chuan)舶(bo)(bo)(bo)用(yong)空載(zai)排(pai)(pai)水量(liang)(liang)(liang)噸(dun)(dun)(即輕噸(dun)(dun)，LDT) 作(zuo)為(wei)買賣(mai)廢船(chuan)(chuan)的(de)尺(chi)度(du)外，很(hen)少實際用(yong)作(zuo)新船(chuan)(chuan)度(du)量(liang)(liang)(liang)單(dan)位(wei)。只是在(zai)(zai)中國，對于(yu)非貨運船(chuan)(chuan)舶(bo)(bo)(bo)類的(de)拖船(chuan)(chuan)、漁船(chuan)(chuan)、工程船(chuan)(chuan)等(deng)，往往使用(yong)滿載(zai)排(pai)(pai)水量(liang)(liang)(liang)噸(dun)(dun)作(zuo)為(wei)表示(shi)船(chuan)(chuan)舶(bo)(bo)(bo)大小的(de)單(dan)位(wei)。

載重噸(dun)(dun)（DWT）：是貨船(chuan)可用(yong)于裝載貨物的最大營運(yun)噸(dun)(dun)位(wei)。一般指貨船(chuan)在(zai)結(jie)構吃(chi)水(shui)(shui)或滿載吃(chi)水(shui)(shui)時裝載的貨物、淡水(shui)(shui)、燃料(liao)潤(run)滑油(you)、爐水(shui)(shui)、備品、供應品及(ji)人員、行李等噸(dun)(dun)位(wei)之和（空載排(pai)水(shui)(shui)量(liang)+載重噸(dun)(dun)=滿載排(pai)水(shui)(shui)量(liang)噸(dun)(dun)）。

總(zong)噸(dun)（GT）：是(shi)(shi)國(guo)際(ji)通行(xing)的船(chuan)舶計(ji)量(liang)單位之一(yi)，是(shi)(shi)登記噸(dun)位的一(yi)種，主(zhu)要用(yong)來衡量(liang)民用(yong)船(chuan)舶的大小（容積(ji)(ji)）。總(zong)噸(dun)是(shi)(shi)指各(ge)航海國(guo)家按照《國(guo)際(ji)船(chuan)舶噸(dun)位丈量(liang)公約》（1982年7月18日(ri)起實行(xing)）制定(ding)的丈量(liang)規范丈量(liang)的船(chuan)舶圍蔽處所的容積(ji)(ji)噸(dun)。

修(xiu)(xiu)正(zheng)(zheng)(zheng)總(zong)(zong)(zong)(zong)噸(dun)（CGT）：是國(guo)際(ji)通行的船(chuan)(chuan)(chuan)(chuan)舶(bo)計量(liang)單(dan)位(wei)之(zhi)一(yi)。在(zai)(zai)船(chuan)(chuan)(chuan)(chuan)舶(bo)總(zong)(zong)(zong)(zong)噸(dun)基(ji)礎上考慮船(chuan)(chuan)(chuan)(chuan)舶(bo)復雜度而(er)計算(suan)出的船(chuan)(chuan)(chuan)(chuan)舶(bo)度量(liang)單(dan)位(wei)，計算(suan)方法為(wei)：修(xiu)(xiu)正(zheng)(zheng)(zheng)總(zong)(zong)(zong)(zong)噸(dun)GT=GT×C，其中為(wei)GT總(zong)(zong)(zong)(zong)噸(dun)數(shu)，C為(wei)修(xiu)(xiu)正(zheng)(zheng)(zheng)系數(shu)。中國(guo)民用(yong)鋼(gang)質(zhi)船(chuan)(chuan)(chuan)(chuan)舶(bo)修(xiu)(xiu)正(zheng)(zheng)(zheng)系數(shu)按船(chuan)(chuan)(chuan)(chuan)舶(bo)行業(ye)標(biao)準《民用(yong)船(chuan)(chuan)(chuan)(chuan)舶(bo)修(xiu)(xiu)正(zheng)(zheng)(zheng)噸(dun)計算(suan)》標(biao)準號為(wei)CB/T3484-2005確(que)(que)定。目前國(guo)際(ji)上均按0ECD造(zao)船(chuan)(chuan)(chuan)(chuan)工作組1994年1月制(zhi)定的修(xiu)(xiu)正(zheng)(zheng)(zheng)系數(shu)表選(xuan)用(yong)。修(xiu)(xiu)正(zheng)(zheng)(zheng)總(zong)(zong)(zong)(zong)噸(dun)不僅比(bi)載重噸(dun)、總(zong)(zong)(zong)(zong)噸(dun)更能(neng)正(zheng)(zheng)(zheng)確(que)(que)反(fan)映(ying)(ying)造(zao)船(chuan)(chuan)(chuan)(chuan)工作量(liang)大小，同(tong)時還在(zai)(zai)一(yi)定程度上反(fan)映(ying)(ying)船(chuan)(chuan)(chuan)(chuan)價高低和產(chan)值大小。因(yin)而(er)，能(neng)比(bi)較(jiao)正(zheng)(zheng)(zheng)確(que)(que)地用(yong)來表示造(zao)船(chuan)(chuan)(chuan)(chuan)產(chan)量(liang)、造(zao)船(chuan)(chuan)(chuan)(chuan)工作量(liang)(新接船(chuan)(chuan)(chuan)(chuan)舶(bo)訂單(dan)量(liang)和手持(chi)訂單(dan)量(liang))和造(zao)船(chuan)(chuan)(chuan)(chuan)能(neng)力。特(te)別是在(zai)(zai)產(chan)品結構(gou)差異(yi)很(hen)大的國(guo)家(jia)之(zhi)間和企業(ye)之(zhi)間進行比(bi)較(jiao)，用(yong)修(xiu)(xiu)正(zheng)(zheng)(zheng)總(zong)(zong)(zong)(zong)噸(dun)作為(wei)統計單(dan)位(wei)比(bi)載重噸(dun)、總(zong)(zong)(zong)(zong)噸(dun)要準確(que)(que)得多。

中國主要采(cai)用(yong)(yong)載重(zhong)噸(dun)(dun)(dun)（DWT）和排(pai)水量(liang)噸(dun)(dun)(dun)，而(er)(er)國際(ji)(ji)上采(cai)用(yong)(yong)較多是(shi)總(zong)(zong)噸(dun)(dun)(dun)（GT）、修(xiu)正噸(dun)(dun)(dun)（CGT）。國際(ji)(ji)造(zao)(zao)船(chuan)(chuan)業(ye)，包括(kuo)造(zao)(zao)船(chuan)(chuan)企業(ye)、船(chuan)(chuan)級社、咨(zi)(zi)詢研(yan)究機(ji)構(gou)(gou)和國際(ji)(ji)造(zao)(zao)船(chuan)(chuan)組(zu)織(zhi)(如經濟合作與發展(zhan)組(zu)織(zhi)(OECD)造(zao)(zao)船(chuan)(chuan)工作組(zu))，在(zai)船(chuan)(chuan)舶生產總(zong)(zong)量(liang)的統(tong)(tong)計(ji)(ji)中，較少使(shi)用(yong)(yong)載重(zhong)噸(dun)(dun)(dun)。只有一些大型常(chang)規貨(huo)船(chuan)(chuan)的造(zao)(zao)船(chuan)(chuan)公司為顯示其噸(dun)(dun)(dun)位(wei)大而(er)(er)采(cai)用(yong)(yong)載重(zhong)噸(dun)(dun)(dun)；一些咨(zi)(zi)詢研(yan)究機(ji)構(gou)(gou)在(zai)統(tong)(tong)計(ji)(ji)貨(huo)運船(chuan)(chuan)舶時也有以載重(zhong)噸(dun)(dun)(dun)為統(tong)(tong)計(ji)(ji)單(dan)位(wei)，但(dan)是(shi)他們更多地使(shi)用(yong)(yong)總(zong)(zong)噸(dun)(dun)(dun)和修(xiu)正總(zong)(zong)噸(dun)(dun)(dun)。作為當今世(shi)界重(zhong)要的國際(ji)(ji)造(zao)(zao)船(chuan)(chuan)組(zu)織(zhi)OECD造(zao)(zao)船(chuan)(chuan)工作組(zu)，在(zai)造(zao)(zao)船(chuan)(chuan)統(tong)(tong)計(ji)(ji)不(bu)使(shi)用(yong)(yong)載重(zhong)噸(dun)(dun)(dun)，而(er)(er)只使(shi)用(yong)(yong)總(zong)(zong)噸(dun)(dun)(dun)和修(xiu)正總(zong)(zong)噸(dun)(dun)(dun)。