by DrPR » Fri Nov 12, 2010 4:30 pm
Joe,
Are you working from station line drawings or a Table of Offsets?
Station lines are vertical slices perpendicular to the longitudinal center line. Waterlines are horizontal slices through the hull at various elevations. Butt lines are vertical slices at regular transverse distances from the centerline.
Station spacing varies from hull to hull. For example, for the 610 foot long Cleveland cruisers station spacing was 15 feet, but it was 16.5 feet for the 673.5 foot Baltimore class ships. The length of the ship is divided into some number of stations and the general lines are drawn onto the hull cross sections at these stations. Later, after the hull lines are done the actual frame lines are created.
The Table of Offsets is much more accurate than hull line drawings. For US ships the width of the hull (transverse or "Z" dimension) is given in feet/inches/eighths of an inch - so 23-7-3 would be 23 feet plus 7 inches plus 3/8 inch. Sometimes the eighths number may have a "+" suffix, meaning that it is more than the value given, but less than an additional eighth (I just add 1/16 inch). I am not familiar with how foreign tables are set up.
These numbers are listed at various elevations (waterlines, or "Y" dimension) at a given station (longitudinal, or "X" dimension).
All elevations are relative to an imaginary "Base Line" on the inside of the keel plating. All offsets are to the inside of the hull plating - the actual outer surface of the framing the plating attaches to. Hote: the hull is substantially wider where the armor belts are attached outside the hull plating.
Did this help?
Joe,
Are you working from station line drawings or a Table of Offsets?
Station lines are vertical slices perpendicular to the longitudinal center line. Waterlines are horizontal slices through the hull at various elevations. Butt lines are vertical slices at regular transverse distances from the centerline.
Station spacing varies from hull to hull. For example, for the 610 foot long Cleveland cruisers station spacing was 15 feet, but it was 16.5 feet for the 673.5 foot Baltimore class ships. The length of the ship is divided into some number of stations and the general lines are drawn onto the hull cross sections at these stations. Later, after the hull lines are done the actual frame lines are created.
The Table of Offsets is much more accurate than hull line drawings. For US ships the width of the hull (transverse or "Z" dimension) is given in feet/inches/eighths of an inch - so 23-7-3 would be 23 feet plus 7 inches plus 3/8 inch. Sometimes the eighths number may have a "+" suffix, meaning that it is more than the value given, but less than an additional eighth (I just add 1/16 inch). I am not familiar with how foreign tables are set up.
These numbers are listed at various elevations (waterlines, or "Y" dimension) at a given station (longitudinal, or "X" dimension).
All elevations are relative to an imaginary "Base Line" on the [i]inside[/i] of the keel plating. All offsets are to the [i]inside[/i] of the hull plating - the actual outer surface of the framing the plating attaches to. Hote: the hull is substantially wider where the armor belts are attached outside the hull plating.
Did this help?