I don’t have the answer for you, but have some information that may help in your search.
I raced my East Coast 31 at Hamilton Island Race Week this year. An elderly guy came to talk to us after racing one day, mentioning that he was a friend of your dad. He also mentioned that he knew the guy that still has a set of moulds for the East Coast 31. You may be aware that a brand new East Coast 31 hull was for sale on E-Bay back in 2017. Anyway, the guy who has the moulds owns an East Coast 31 called Volo, which is moored in Kooroora Bay, Lake Macquarie. I don’t have any contact details, but perhaps someone at RMYC Toronto may be able to give you a lead.
Also, a Traditional 30 (Take 5) raced in the 2019 Sydney Hobart. As the hull design of those is very similar to the East Coast 31, perhaps that may be another way to get some similar hull plans.
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