water strainer seal gasket

Good morning. I have not succeeded in finding a seal gasket for the raw water strainer on a 73 47 Commander. Does anyone know where I can find one?

It has an OD of 5.75 in, a width of about .25 in, and a thickness of about 1/16 as measured by a micrometer -- It is neoprene.

Thanks in advance for your help.

Regards,

Dennis