Exceptionnel. Une première. Un témoignage inattendu en provenance des Etats-unis. Sans autre commentaire, le voici:
Hello,
I apologize for not writing in French.
I own an Arcoa 520 that is titled as made in 1960. The number “99″, or maybe “66″ (who knows which way is up), is stamped in several places in the boat, mostly on the plywood floor panels and other removable pieces. It is a wood sailboat, with strip mahogany veneer above the waterline, and a set of yellow sails as pictured in one of the documents you have on the site. 
And a BD1, I believe. The gentleman I bought it from said the motor ran, but was not easy to start. I have not gotten that far yet.
It is a restoration project, needing a new cabin top, foredeck, some new wood for the keelson, some re-gluing where the mahogany veneer has lifted, and of course, a general refinishing.
It is missing the “Arcoa” name plates on the sides of the cabin. 
If anyone could provide me with a measured image of one, and an idea of the original material and thickness, I would appreciate it. Also, was the deck covered in canvas originally, like the cabin top?
A few pictures are attached.
Thank you for a wonderful website preserving the memory of these lovely boats.
Walter P.
Michigan, USA
Si quelqu’un dispose d’un logo arcoa en métal, tel que ceux qui été appliqués sur les parois latérales des roofs, et qui est prêt à le céder, je l’enverrai volontiers à Walter pour le remercier de nous avoir envoyer ce message, et en espérant qu’il nous tienne informé de l’avancement des travaux.
J.Loubet
28/05/2011
I hope you can do the best for your boat because he seems beautifull.
For your question, i have a number “10″ who is stamped in several places in the boat, mostly on the plywood floor panels and other removable pieces in my Arcoa 600. I don’t know what represent this number.
Best regard’s for the USA arcoa member.