1920's Naval Architecture Terms

I'm currently in the process of trying to figure out some terms from an English motor yacht built in 1920. I have the lines plan, table of offsets, hydrostatic curves, launching hydrostatics and some GA drawings. I've made a model and the displacement works out but I'm have trouble with "referenced" measurements, LCB, LCF, VCB.

Some longitudinal measurements are taken from the "Locus of the LCB" and some vertical measurement are taken from the "Scrag." These are terms I've not run across before, can anyone help out?

 

Scrag is the neck ? Not sure if boats have necks ! Locus of the LCB seems somewhat self-explanatory ?

 

Locus simply means a particular point or place.

As for scrag, maybe it's from the Danish "skrog", for (apparently) the hull of a ship?

It sounds like one of the cross beams has gone out askew on the treadle and you're doing your best to cope with the report of it.