There has been a lot of discussion about this recently. Heat is the answer.
https://www.hobie.com/forums/viewtopic.php?f=70&t=62288Airsails wrote:
Just finished the upgrade on my 2011 Tandem Islander.
Removing the AKA knuckle lock plates can be difficult and result in broken screws, here is how I got mine out.
All mine were seized, this method removed them with no sheared heads or damaged threads.
First you remove the plastic lock plates with a pair of side cutters and pliers, they break off fairly easily.
Next, using a heat gun, heat each screw head in turn. They need to be really hot, I measured the temp using a laser thermometer and got a max reading of 350 degrees C. Takes up to a minute with the heat gun 2 cm from the screw head to get them this hot.
Now while hot, use a screwdriver to wiggle the head back and forth, shouldn't take much effort to remove them, if the screw is still tight, heat it more. My screws took on a brown tinge when they got hot enough. You won't damage the metal parts with the heat gun, it isn't hot enough for that.
I applied grease to the threads when the screws went back in to help stop corrosion.
Having a 6-32 UNC tap to clean the threads out helps when reinstalling the screws.