Having had a closer look at the Great Dane 28’s data, I think she deserves her own thread, so I jump from the Magazine 84 thread to here.
At first glance, the GD28 looks quite normal for her time, not very dissimilar to my IF, Ingeborg. However, her displacement (3800 - 4200kg) puts her among the real heavyweights.
Her Disp./WLL. ratio is around 400, which puts her in class with the Nicholson 32 (Ingeborg: 270).
The description I find about her (in Swedish) indicates that she was designed for serious ocean travelling, but it also indicates that she is under-rigged for normal sailing.
Her SA/disp is around 13. This is where the JR can help. Even with a shortish mast, as shown below, the SA/disp. can be brought up to over 16, which is decent. With a camber/chord ratio of 8 – 10%, she should move well, and no doubt sail in rings around an original sister boat.
On the sailplan below, I have reduced the boom length from 5.2 to 5.0m to bring the CE a bit further forward. In case I have overdone it, the whole sail can easily be shifted a good deal aft, to get her in balance. How tall the rig can be made, depends of available mast material. I guess I would not go higher with aluminium or wood, but a light and strong carbon mast could justify a taller rig.
The traced hull and in particular the underwater hull has been taken from quite low-res diagrams on the web, so are quite inaccurate, but hopefully they are good enough for this exercise.
Arne