Hi Julian,
The transom of a boat is the flat(ish) bit across the rear end and , if your boat does have a HIN (or pseudo HIN), it will be moulded into the fibreglass near the top of the transom, probably on the starboard side, maybe port, to be read from outside. Again, I don't think I have a photo of Wild Thyme's pseudo HIN, which she certainly has. I must get some photos of these features when I'm next aboard her this coming week.
A pseudo HIN is a term I unvented for a number looking a bit like a HIN made up by the builder before the EU recreational Craft Directive required HINs on EU built yachts. Moulded in HINs were required in N America well before the EU so EU builders who wanted to sell into N America were often being asked where is the HIN - they resolved the matter by inventing numbers of their own. In the case of Wild Thyme, built in 1988, the pseudo HIN on her transom is based on the number of her Lloyds Certificate, but is not actually mentioned on either the Lloyds Certificate or the Builders Certificate issued by Marine Projects.
Peter.