Since you are located out on the sand bar, you might want to take a ride over to Karl's Boats on Great Western Road in Harwich. If Karl can't find or make a board for you, then you are in a tough spot. He has never let me down on any sailboat related repair or upgrade that I have ever sent his way. He does some really nice high end tuning work too.
The original board fell off the boat at the mooring.
Karl re-installed the original board and charged labor cost of $2000.00 It fell off again the next time out and was lost.
Karls Boat Shop installed the Foss Foam board for me and the labor charge alone was $1500.00
The new board he installed fell off last month and is split along the edges.
Both times I had the boat in his yard,while on the lift slings he left the cabin hatch open and when I picked the boat up both times there was three inches of stagnant rain water in the cabin. This, after my asking and insisting the workers keep the cabin hatch way closed. It took me three days to clean the inside cabin, cushions, and mattress's and equipment,they still smell moldy. Not sure I'll be going back to Karls.