Thanks for everyones help, I have got the plans now and the hull. I have scanned and blown up the drawings to 1/72. The model is only goinfg to be a suface runner for two reasons;
1. Their diving reputation was awful, they seemed to spend a lot of time nose down in the sea bed.
2. I want to see if I can squezze a small foggy inside to get some authentic looking smoke out.
Like the picture Andrew, I am planning on building K3, what scale is your model?
Mark