Removing the trampoline frame off the hull posts?

I need to remove the port hull. I noticed the single bolt on each side had a plastic nut which kind of surprised me. Easy to take these of but why is the hull post not just falling off. I see no movement and do not want to put pressue on the hull. Is this normal?
Maybe WD-40 spray?
I'm assuming it's a H16? If so, take the bolts out of all 4 corners. Once that's done, use a rubber mallet and hit upward on the corner castings to loosen them up. Make sure to use a rubber mallet or block of wood so that you don't damage the castings.

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Tim
81 Hobie 16
87 Nacra 5.7
Austin, TX
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The corner posts can be stubborn! I epoxied the entire frame of my H16 last year and to help pull the castings off the post I used a scissor jack. Placed it between the hull and the casting and with a LITTLE pressure and tapping with a wooden block it came apart easily. Just be sure to use some padding on the hull and don't use too much pressure to avoid "crushing" the fiberglass! Move front to back a few times. As long as you are pulling one hull you just as well pull the other one and epoxy the whole frame. The stiffer boat makes a lot of difference in handling!
Got it guys! I turned the Hobie 16 upside down and put my blue barrel dolly under the hull in the rear and used a 2 x 12 x 36" board to hit down on the casting. After a few good hits and using WD-40 the hull finally came off. After my post, I thought, that was a dumb post!. I was just afraid of ruining the hull. Thanks!