(2) Where to plonk the mast - CLR

Stage 1. Practical Junk Rig page 92:  How to work out the Centre of Lateral Resistance (CLR). Make a scale Drawing.
The weather is fantastic.. what more do you need but some helpful assistance (Artie the willing),  a measuring gizzie and the boat sitting on the trailer to take all the necessary dimensions to result in a scale drawing  on A3 size graph paper.. piece of cake!! (yeah)... Luckiliy, Robin Blain (Junk Rig Association) kindly gave me a copy of the original Colvic Watson sales bumf and some photos of  another conversion job, so not only having some dimensions and outline drawings, I have something to compare my results to!!
Unfortunately, my first result looked more like the ruddy Titanic than Bobtail (very worrying?!).. so recheck time, this time with a 3 mr "ruler" made out or a piece of 2x1, Much better as I hadn't measured the gap under the keel properly (idiot).. but result is now as accurate as I can make it!
From the scale drawing, we made a tracing of the under water profile (incl the rudder),  we then folded it into a concertina shape so it didn't flop about and then see-saw'ed it on a knife ... when finally we managed to balance it, the fulcrum point is the CLR... wow, what fun!
It was Blue Peter time again, the only thing missing was the proverbial toilet roll tube ? (if you don't know what I am prattling on about: you are too young!!)...
Anyway, from this we transferred the information to the Scale drawing... cool!
The next step it to work out the Centre of Effort (CE) of the proposed sail and how this relates to the CLR of the hull. Apparently this should be somewhere between 5% -  9% of the length of the water line forward of this CLR, this will then identify where the mast should ideally be... there are a number of things to consider (listed on page 110 and 119) to achieve this. It seems a bit complicated, but involves more bits of paper and card to cut and pins and string and scissors (no crayons though) ... what fun: more Blue Peter stuff!!

The end result of where to actually plonk the mast will still be a bit of a compromise, despite the theory. There will be a lot of windage area on the stern as I aim sail inside the wheelhouse with the full canopy up, this could have some considerable impact on the lee/weather helm effect on the rig, so whatever I do, I must be able to adjust position of the mast or rake it (etc) after I have done some real sailing ..
Later, darling, later, but happy days: we will need a touch of Harbour Acceptance Trials, just like in my old job with the MOD(N),  my motto was:
 "Don't cross bridges sunshine, if you have two birds in the hand and cant get through the eye of the needle because the bush is too big"...
Confused ? you betcha, join the club ha ha!!