How to develop frames without buttock lines?

[alpayed]

Hi Tony.

It's a long explanation but the shape of the hull is essentially derived from the stations. amidships and fore and aft are constructed from a few basics, floor harpin, breadth sweeps, floor sweeps, etc. Both the waterlines and buttock lines are a method of controlling the hull form largely at the bow and stern. There are no formulas or graphical means (like controlled sweeps) to develop these areas. They were largely at the whim of the designer.

There is more than enough data above to reconstruct the hull form above. The waterlines and buttock lies can be extracted from the stations given. the bow and stern shape can be derived also. The buttock lines are shown beyond station 10 which is where they are most useful. in developing the waterlines and buttock lines they are played off against each other until the hull form is fair. In the construction of the lines below I also used what I refer to as control lines. these are developed somewhat at right angles to the waterlines. The hull form is plotted into this view and the shape smoothed out. The points then projected back into the body plan and sheer plan and the waterline/buttock adjusted as required. See also the pdf on understanding ships draughts.

understanding ships draughts.pdf This playing off of the lines is repeated many times until the hull form is properly faired. The mid body is well controlled by the floor harpin, breadth sweeps, floor sweeps,rising line of the floors.

 

Regards Allan

Edited July 16, 2021 by alpayed

[tkay11]

5 hours ago, alpayed said:

in developing the waterlines and buttock lines they are played off against each other until the hull form is fair

 

Thanks very much, Allan. I especially enjoy the idea of 'playing off against each other'. This is very helpful. I also appreciate the pdf, which adds significantly to other tutorials such as Wayne Kempson's 'Drafting ship's lines in CAD'.

 

Tony

[AnobiumPunctatum]

Quote

Thanks, Christian, for reminding me about your Triton build. A really great undertaking. I really appreciate your plans reconstruction. How is it getting along? Have you yet decided to get back to a build?

 

All parallel frames and fore cant frames are finished. In the moment I am busy to draw the after cant frames. Then the hawse pieces and transoms will follow. I hope that I continue with model building next year. But all planning is dependent from my job.