Hello, my party has an airship that we are trying to figure out how to cloak or camouflage while we're not docked.
We've thought about invisibility permanency on the ship, but we're not exactly sure what size area that would cover; if it would work for the boat.
I'm trying to find other ideas that could work as well. Please advise.
Target you or a creature or object weighing no more than 100 lbs./level
Invisibility might work on an airship if your GM allows net weight rather than mass, but that's unlikely. Area is not a limit though.
Mage's private sanctum (with or without permanency) disguises what your airship is but not the fact that something's there. Fog spells would have a similar effect.
If your airship can be deflated/disassembled into to fit into a 20' cube then hide campsite would work.
Hallucinatory terrain could make convenient illusory trees to hide your airship.
In another edition, I managed to snag a cloud castle. Travel to and from requires teleport or some serious flight ability. Dim door is not enough.
This exact scenario happened in my current campaign. The party got an airship and visited a wizard (whom they dubbed the nickname McWiz lol) to make it permanently invisible. I got tired of trying to accurately calculate the weight of the ship and how much it would actually cost to make the ship invisible, so I said screw it, it costs 25,000gp and your ship can become Invisible whenever it is not moving (because I still wanted the liberty of having random aerial combat encounters, but still giving them the liberty of hiding the ship whenever they were in port), but it comes with a flying invisible rowboat that can seat 10 medium creatures and can fold up like origami and fit in your pocket when it's not in use. They were happy and I was happy.
Other than what's already been mentioned there are a couple of other spells that could be used that can be made permanent.
A few castings of the the spell Loathsome Veil would make it so that creatures want to avert their eyes. They would know something is there but they wouldn't want to look at it to figure out what it is.
There is also the spell Stolen Light. It might take multiple castings but I could see having 4 or more permanent versions of the spell placed around the ship, such that when all of them are activated the ship is fully encapsulated. At that point you just have to decide ahead of time what you want the ship to look like. If the DM is really nice they might let you spend some extra gold to allow you to change the image or have several pre-set images you can switch between.