update:
local library supplied the following -
Booth, Graham 'The Narrowboat Builder's Book' 3rd ed (1999) isbn 1870002717
not enjoying the general design of this book - a little too busy with unclear illustration and poor reference between pics and text - as for content hard to assess as I am not putting theory into practice quite yet!
Billingham, Nick 'Narrow Boats (sic): Care and Maintenance' (2003) isbn 1852238615
proved much better for me to 'zip' through - enabled me with 'nb' terminology and a better orientation of things 'technical'.
Thanks: end of thread?