A hook and loop fastener on steroids.
The 3M Dual Lock Reclosable Fastener features 250 stems/in2 for a secure hold. This version is a clear 1" wide strip with an adhesive on the back. Sold by the inch in up to 48" lengths depending on availability.
The advantage of this style of reclosable fastener over typical Hook and Loop tapes is that the holding power does not degrade when wet. The polypropylene stems do not absorb or hold water and work well in the marine environment.