Getting things to stick to polyethylene can be challenging.
Pretreat by cleaning, sanding with 100 grit sandpaper, wipe down with rubbing alcohol
The following adhere well without any heating or significant plastic dissolving

Remember that the velco adhesive doesn't hold well in the heat of the summer.
Duct Tape can hold whatever you want in place till, Gorrilla Glue, Silicone or Marine Goop cures.

You might consider combining some Strong Magnets & Marine Goop on the inside of your yak to hold loose Lures, Pliers, Hemos, Clippers & Hooks to the deck, cockpit walls, Hatches or just about any place
Examples:





Big Red showed me this trick

Great tip with the magnets. I spread on some 3M automotive adhesive (designed for engine work) to the back of the velcro strips--should help with the heat tolerance. Using the velcro to help secure AGM battery in battery box (along with some carved foam planting knee pads and carved/cut yoga foam blocks.
yoga foam blocks


Foam kneeling pads


Found the blocks and pads at BigLots real cheap

Nice tip on the magnets

don't forget this adhesive, one of the very best! sascho Lexel Caulk Tube

Forgot about Lexel--my neighbor let me borrow some one time -- good stuff.

There is a wholesale magnet distributor in Plano that if you can imagine a shape and strength they have it. I suggest you stick with the Neodymium magnets because of the strength and size ranges available. I believe most are nickel plated and not sure if they will start to rust. May need to check on that before installing or you could just cover in the goop used to attach to yak.

The website is magnet4less.com if you want to see their offerings.

www.magnet4less.com

also hear old hard drive magnets are pretty strong. nice way to hold metallic objects to the yak without having to
tether or velcro them down. ill be adding some small but strong magnets soon to my rig