Chapter 1 . The Lines plan
Ok. Here we go. The is the first of a series of articles which will chronicle the design and construction of a GRP sailing boat as it happens (more or less). I would like you all to follow progress and chip in with ideas, questions and suggestions as we go. I figured I would start with the linesplan since when I build a boat I start by drawing a?.. well you get the idea.
The linesplan is the cornerstone of a yachts design. It defines the shape of the hull and allows the designer to calculate the areas and volumes and where they are positioned in relation to the weights and forces that drive a boat through water. In other words is it gonna float or sink and will it fall over.
Have a look at the attached file. Its in JPG format so most of you should be able to read it (If you want a more detailed, full size printable PDF just let me know)
Beautiful, isn?t she??.<sigh>
Do you reckon it looks like a Twelve metre? As I stated in an earlier post I wanted a new hull under my old EC12 rig so here it is. She is big, fat and heavy. GO DINOSAUR POWER! No fins & bulbs here folks. The hull-only displacement is 11kg, up to nearly 12kg with keel. Big (well biggish) stable and good to sail.
Notice there are basically three views, each view showing ?slices? of the hull.
Starting with the body plan, you?ll see it shows the stations. These are the transverse slices of the hull, usually spaced at one tenth of the waterline length. Station 0 is generally at the forward end of the waterline and Station 10 at the aft end with the negative numbers defining the bow and those above 10 defining the aft overhang.
By looking at the profile you can position each of the sections as well as seeing her buttocks (I still remember the disappointment I felt turning up to class one day, seeing my fellow students all gathered around a desk muttering something about nice tight buttocks and bulbous bow only to find they were talking about a trawler??) Anyway where was I. Yes the buttocks are longitudinal slices through the hull. In this case they are spaced at 25mm and so are labeled Butt25, Butt50 and so on.
Finally there is the Plan View. It shows the shape of the various waterlines as well as the diagonals. The waterlines are the horizontal slices through the hull, again spaced at 25mm in this instance. The DWL is the Design Waterline and is position at which the boat is supposed to float. (Gotta keep track of the weight!)
The diagonals can be seen on the Body Plan as well as the Plan view. In this case there is one at 30? and one at 60?. The view in the plan view is a true view looking square on to them. These are a good final check to make sure the hull s fair. (Look around the aft end of the diags and you?ll see some funny shapes caused by the typical 12 metre style bustle)
So generally that?s about it for Lines plans from me.
Please post any comments and suggestions??.
Up next Chapter 2. From the Drawing Board to Reality
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