Arne, thanks for reminding me that I should be placing more of my notes into my pages on the web site.
I’ve spent a lot of time trying to produce a table that would give all the answers to the Round and Broadseam calculations, and each attempt has ended up with more work for the sail maker to do. My original spreadsheet is still the simplest way to do the sums, so now I’ve tidied it up so that it is only necessary to put 3 numbers in three boxes to complete the calculations for a parallelogram panel. Arne has seen it and 1) suggested colouring the print to highlight the input boxes, and 2) using his knowledge of a foreign language, correct my spelling in my native language!!!
After many experimental calculations at the beginning I ended up using what I called a ‘Round Factor’ (fudge factor) to work out the rounding and has been built into the spreadsheet from the beginning, and if I remember correctly I used 0.5 or 50% for the main panels on Poppy, which were not critical. It has crept up with later designs, but has always been between 50 and 56%. The figure of 55% that Arne is quoting on page 4 of his 'Chain Calculator' seems to tie up well with the figures I've been using.
With luck I should get the spreadsheet and explanation into my notes on the web by the end of the weekend. The details of the combined downhaul/ batten parrels should follow shortly.
Cheers, Slieve.