为了缩短船舶建造周期及保证船舶下水的大节点，轴系、舵系中心线确定在舵机舱平台以下所有焊接、火工矫正、密性等全部结束并报检通过后即可进行照光。
In order to reduce the building time and ensure the node of ship launching , the jobs under steering gear cabin deck such as blocks erection、erections welding、distortion correction by flame、tightness and so on should be finished completely ,after finishing these jobs ,we will decide the centerline of shaft line & rudder line.
1. 工具的选用
Tools and instrument
激光经纬仪、光靶。Laser theodolite and optical target.
FR-2
图1FIG. 1
2. 轴系中心线的确定
Decide the centerline of the shaft-line.
轴系中心线的确定应根据季节温度变化来进行，夏天一般在晚上8-9点进行,冬天一般在下午5点左右进行, 或在阴天进行，在轴系中心线的确定过程中，船上不应有能够导致船体变形的工作在进行。
This step should be done according to temperature change of the season of a year , in the estival season , this work should be done at evening 8-9 clock, and in the winterly season, this work should be done at afternoon 5 clock ,or in the cloudy day, and any work that can bring hull deformation should be stopped.
1）船体尾部理论轴中心面的确定。
Decide the center plan of shaft line outer of E/R.
①以中心线在船台上的延伸点为基准，调整激光经纬仪“1”的轴线直至与船
中心线重合。
Adjust No.1 laser theodolite centerline overlap with hull C.L. basing on
hull C.L.
②将激光经纬仪“1”射出的光点延伸到船台尾部光靶“3”上，根据机舱区
域舱底龙骨平整度数据平均值为基线高度并在垂直方向向上平移轴系高度+
船体板厚，则此点为轴系轴线上一点。以此点作为参考点并打好样冲点，
同时将激光经纬仪旋转180°将光点投射到尾柱上，并打好样冲，这样就
可初步确定轴系尾部理论面。
Extend the laser from No.1 theodolite to No.3 target, then according to the mean valve of flexibility of the keel under the ring of groove for main engine as datum high move No.1 theodolite up and down in vertical plan and measure the height of shaft line and thickness of armor plate, the point as a datum point in the shaft line, a laser point can be found in stern boss by turning No.1 theodolite 180°, and another mark will be made as the point. In this way, we can decide shaft center plan outer of E/R firstly. 2）机舱内轴系中心线的确定
Decide the shaft line in E/R.
①在机舱与尾管平面适当位置设立一激光经纬仪“2”，将光点延伸到船体外
部的光靶“3”，使之与光靶“3”上的样冲点重合。
Put No.2 theodolite to fit at Fr15. Its laser beam to be extended to No.3 target and to be kept superposition with that mark made on No.3 target.
②调整激光经纬仪“2”的位置，使之既能与船体尾柱上的样冲点的连线相
交，同时也能投影到光靶“3”上的样冲点上，调整经纬仪高度与光靶
“3”上的样冲点重合，然后将经纬仪“2”的位置固定。
Move No.2 theodolite, and keep its height same as the mark on No.3
target and make the beam pass through the center of marks on stern
boss, then fix No.2 theodolite.
3）轴系中心线的延伸
Extending the centerline of the shafting.
①将激光经纬仪“2”调转180°，将光点延伸并投影在机舱Fr40舱壁上，
并确定光点位置，打好样冲点，这点与光靶“3”上的样冲点的连线即为初
步确定的理论轴线。
Turn No.2 theodolite 1800, the laser beam can be extended to Fr40
bulkhead, make the mark again. Now we can say that the line decided by
this point mark and that one on No.3 target is shaft line.
②检查主机底座中线与理论轴线的偏离距离，偏移范围在±（5-10）mm之
内。
Check the deflection distance between base line and shaft line. Allow
deviation range to be within ±（5-10）mm.
3. 尾轴管镗孔时轴线的确定
Deciding centerline of stern boss
1) 加工圆确定前的条件
Preparation for this step
①本船上所有设备都已安装到位或用重量相当放置在相的物品应位置上代替。
All other equipments should be located or instead by others as same as
the weight.
②在本工艺进行的过程中，船上应停止冲击和有振动性的工作。
When this step being done, any impacting work or vibration job should be
stopped.
2) 定轴系中心线
Decide the centerline of shafting.
如图所示将激光经纬仪“2”放至机舱适当位置（如“图-1”所示），调整高
度和左右位置使射出的光点既能投影到光靶“3”上的基准点上，又能在旋转
