The first thing to understand is the shapes we use are only to show the points where the lengths are measured and are not meant to show the exact shape of shade sails we manufacture.
The diagonal lengths dictate the shape and are absolutely essential in producing the shade sails accurately.
As a simple example the diagrams here shows three shapes all of which have four sides, each 600 in length, but varied diagonal lengths of 846.17, 993.77 and 1155.89 which significantly alter the final shape and dictates how we make the shade sail structure.
You might have a four sided shade sail structure but want an extra mounting point on one side. If that were the case you would choose five sided and divide the side where you will have the extra mounting point as shown in the example of a five sided sail with one continuous edge (lower)versus a true five sided shape.
Likewise if you had a four sided shade sail and wanted six mounting points you would choose the six sided formula and follow a similar method. You will also see here how the diagonals define the final shape
It is important to understand that all our shade sails have parabolic curved edges. Without a curve it would not be possible to obtain good tension on the shade sail. The curve is concave (inward) and at the midpoint would be about 8% of the length of the side.
As the shade sail is tensioned this reduces to between 3% and 6% - depending on the tension.
Take your measurements from mounting point to mounting point as shown in the graphic.
When you get the shade sail Quotation we will ask you if you want us to make the shade sail to be "actual" or for us to make "allowance"
We also give you the option for us to include the fittings.
We supply one turnbuckle and one D shackle for each connecting point.
For shade sails up to 35 M2 (376.73 ft2) we supply 8mm fittings, above we use 10mm. All fittings are 316 Marine Grade Stainless Steel.
The combined length of the extended turnbuckle and the D shackle is 32cm.
When we receive an order it is sent to our pre-production department where they produce a CAD (Computer Aided Drawing) of the shade sail. This CAD provides the dimensions for the factory to work with.
If you have specified "ALLOWANCE" we take away 32cm in the direction of tension. Below is an actual CAD used for an order
The outer dimensions are the actual dimensions and the inner dimensions after allowance. Note the 32 at each mounting point.