Then it would be a Lizard Lifeboat!
Then fix the clear capsule (Lizard Home) to a part of the rigging
(Does your boat
have a mizzen mast
?) and then let the lizard come and go as it wants. With suitable cat proof placement or smaller holes (big enough for lizard, not big enough for cat to enter), this capsule could be a cool way for the lizard to be seen and yet safe.
Attach a bit of something to the outside of the capsule (near the entrance) to hold a small piece of food
for flies, and then the lizard can come out for a bite of some fresh soft fruit or insects when it wants.
Of course the cat may find the lizard appetizing, but that is a different problem.