Fishing Craft Technology

Practical 7 - Buttock lines and bilge diagonal

1) Aim: To draw the buttock lines.

Procedure:

• Draw the vertical lines parallel to and at equal distance on either side of the centre line on the body plan (say B1, B2).
• Note down the points where buttock line meet the body plan line (say BX8, BX9, BX10, BX11 etc.).
• Measure the distance between the reference line and the points which are noted above (Eg the distance between R and BX9).
• Transfer the above distance to the sheer plan at the same station
• (say 9).
• Repeat the same procedure for the other points at different sections.
• Join all these points to obtain buttock line.

2)Aim : To draw the bilge diagonal.

Procedure:

• Draw the diagonal lines to the body plan on both sides of the centre line (say D1 and D2).
• Note down the points where these diagonal line meets the body plan line ( DX2, DX4, DX10 etc.).
• Measure the distance from centre line to the above noted points (eg. the distance between C and DX2).
• Transfer the above distance in half breadth plan at the same section.
• Repeat the same procedure to other points.
• Join all the above points to obtain bilge diagonal line.