That's especially surprising, since most boats are relatively low dust environments, unless you're actively working on the boat, like sanding woodwork, or have a pet aboard.
You're not living aboard are you?

Clothes in and out of lockers, towels, and last but not least, the bedding. With the two of us on a 32-footer, we tend to dust every day. erh, sorry, not me, but the other, and much more important half,

Exactly. All the dust from living ashore in 10% or less of the space.
In addition to the listing above, the fuzz from pulling a Kleenex from the box, turning pages of books, dust from every piece of fabric every time you move, all in a pretty dry environment, particularly (at least for me) in winter.
Kudos to IBM/Lenovo by the way. The new fan came yesterday midday. Popped right in and the laptop is perking right along so cool and quiet.
Now I am scratching my head over whether to get a spare fan and spare keyboard or just get a netbook as a spare computer.