Cutting Holes in 5mm fabric reinforced Neoprene

[Motor_Sailor]

Use a club hammer with the wad punch & use something like an (MDPE?) chopping board underneath to punch into so you do not damage the edge ,but essential that all is supported on something with mass not a flimsy bench.
Jim

Absolutely. Every essential detail.

On the sail loft floor you can only do this when directly over a substantial major floor joist. A couple of inches either side and it never works. Solid concrete floor would be best.