Question: I recently had the bilges of my narrowboat painted. They used a paint with two components that needed to be mixed, and warned me that it contained 'isocyanates', and to avoid sleeping on the boat until the fumes had cleared. 

They said it was aircraft paint they had left over from another job, and that it would be very hard and so good for preventing rust in a place which is unventilated, damp, and uninspectable.

Initially the smell was overpowering, but they told me that the fumes would go away in a week or so. 

A month later, although the smell has gone down a lot, there's still a smell of paint fumes in my bedroom. 

Does anyone know what these fumes are likely to be? The smell itself isn't too troubling, but I wonder if they're poisonous. 

I tried sleeping there last night, and woke up with a slight sore throat and have had a mild headache today (might be coincidence, of course...)

Any good ideas for getting rid of the fumes, apart from the horror option of ripping up the whole of the boat and grinding off all the paint and re-doing it? Will they eventually just go away on their own? Is there any way to speed the process?

Answer: 
I'd say put it inside the closet.
If you get false alarms, consider moving it.
Else, it's the best place to alert you.

Chances are if the boiler is working well, you'll never hear a peep from the detector. Hopefully you did get the type that shows you the CO level, so you can check if you're getting zero or something higher.
The detector is there to protect people not the furnace. It should be in the living space not the utility space. And you should have one on each level