#10 Martexin Original Waxed Canvas
The original waterproof material from mother nature, this was the material of choice for loggers and outdoorsmen long before Gore-Tex was a thing. An all natural cotton duck is impregnated with a proprietary blend of beeswax and linseed oil and gets a beautiful patina as it wears that some compare to leather. I buy mine from Fairfield Textile in New Jersey. The minimum orders and per color cut fees make it expensive to stock which is why it is so costly to upgrade your bag. I think it works really well reinforcing sailcloth and paired with leather for a truly classic look.