Hello all,
Iam struggling to understand the offset table and need few clarifications as I am new to ship design
I understood offset data has two tables
1.Half breadth- the width of the waterline at each station measured from the centreline.
2.Height above baseline- the height of each buttock above the datum line.
I just don’t understand how to meaure Main deck side/ Main deck center and keel for the height above base line table.
Im measuring the vertical distance of each station at interaction with buttock line. Please help me out.
Body plan and offset table attached as JPEG file.
Awaiting feedback.
Thanks.
Nick
I don’t know whether these will answer your question directly; but I think you’ll find them useful as an overview of lofting. Each of them ~25 minutes.
Nick,
The Half-Breadth Table to the left is telling you that the edge of the main deck at its utmost point is, in the case of Station -1/4, 5307mm off the center line of the vessel.
The Buttock Table is telling you that the main deck at side, in the case of Station -1/4, is 4700mm above baseline. The main deck at center datum means the main deck is, at Sta -1/4, 4775mm ABL.
so that makes 2 sets of coordinates for you main deck line. (0,4775) Main deck @ CL and (5307,4700) main deck at edge.
So measuring off your 5 meter buttock you come out 307mm and up 700 from the 4m waterline.
See?
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Wow, is somebody continue to do lofting manually ???
He’s fixing up an old (?1928?) yacht named Tally Ho. Time he gets done the only original bit will be the coin under the mast foot.
Offset table used very seldom now. Designers sent to shipyard 3D models, but from time to time, it is necessary to refresh your knowledge how to put it into computer…
State of arts old lines drawings and offset table.
