While this may not particularly be an "exploit" so as much just a simple "glitch", it's quite fun to amuse yourself with between waiting for mail from tradepacks. The harpoon system for Clippers is a smidgeon buggy when you attempt to shoot at object above a surface in front of you and can allow you to sail into the skies! This trick will generally work if there is any sort of straight, vertical surface. While it won't let you do too much, you can occasionally swing from the skies and bump into ships coming into harbor.
This sort of trick can be done when your ship is sitting on land as well, to an extent. Attempting to shoot the ground behind you (or too outside the regular scope for the ship) will cause the aim to shoot slightly towards the sky, allowing you to very slowly but steadily ascend. However, this trick cannot be used once you're too far away from a regular surface. I hope this provides some fun!
An idea on what is looks like:
Step 1) Position your Clipper facing towards the surface you're going to be climbing.
Step 2) Attach yourself to a surface above you as much as possible and begin to reel yourself in.
Step 3) Once you begin to ascend, attempt to re-attach to the surface. Due to the position of the camera, targeting will tend to become inverted for whatever reason. So by hovering your mouse over a position on the surface, you will see the reticule hovering in the blue. It takes a bit of fidgeting the position to get a good shot.