Help! Hobie Anchor Trolley installation problem

I've searched and not found my problem addressed. I'm trying to install the Hobie Anchor Trolley on my 2014 Sport. The bolts for the cheek blocks require a washer and locknut on the inside of the boat. Not a problem in the bow, but can't access the stern since the Sport doesn't have a rear hatch.
Can anybody suggest a remedy? What kind of screws could I use? THX !!!

I would suggest what is called a wellnut.

But in anycase, here is a great video runs you through the various options

https://www.youtube.com/watch?v=GHWHpGhjtUs

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2014 Hobie Outback set up for rod and longline fishing

WOW ! Thank you so much, several good ideas there.

What a great video ! Thanks Mahi.

I finally got it completely installed this afternoon after much fussing and ordering new parts and starting and stopping.
I ended up using both wellnuts and 3/16" tri-fold rivets. And replaced some self tapping screws from older installs with rivets. And added a zigzag cleat.

What prompted the install was I hooked a Goliath Grouper last December in the Keys....and was using an anchor trolley.
Going down again next month for some bonefish.

Nice work DCR! Setting my kayak up with all that type of thing was all part of the fun and very satisfying when finished.

Wow a goliath grouper that would have been awesome! Good luck with the bonefish

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2014 Hobie Outback set up for rod and longline fishing