James,
You state that you are re registering your boat. Therefore, there simply had to be a builders certificate if she was on an official ships register anywhere before. Ergo you should have or be able to obtain a builders cert. copy at least.
The EU certificate of conformity, as far as I am aware, only becomes relevant to vessels made after 1998.
Contacting a genuine registration broker in whatever country you are trying to register in, would help give you a clear understanding of what exactly is required and how to obtain it.
It took me nine months to delist my SM from France and re register in Ireland. It was all uphill. The biggest obstacle being, that the vessel was lying in France and the Irish authorities wouldn't accept the majority of surveyors prepared to undertake the work which primarily was confirming that the boat physically existed. Lloyds turned it down stating it was simply too difficult.
Ultimately, the official register of official Irish registered ports, has the discretion to accept of reject a vessel onto their list and I eventually found a reasonable port officer.
When the boat was eventually sold on to an American buyer, despite providing him with copies and samples of all documents prior to contract, I believe that he had again, had a very difficult experience putting the boat on a US flag.
It is a difficult and often contrary process.
Good luck.
Trevor Lusty
Ireland
