Dry, really dry, bilge.

I've used a "proper" one after spillages in the engine bay. The oily gunge ends up in the vac container where it is much easier to dispose of. liquids shouldn't reach the filter should they?

It's £16, try it.
Mine was a tenner from Argos about 15 years ago IIRC.
I felt it was just about worth the tenner, but I was paid more in those days.

These days I'd probably just put on my industrial gloves and use a bucket and j-cloth.
For sucking up dirty water I might use the Pela, if it's to hand.

Wet vacs come into their own when you've got a mixture of water and stuff the pela won't handle, like sawdust or bits of seaweed or something. But you usually want a proper 800W one.
12V stuff is so often mostly 'giftware'. Silly toys that are slower than the manual option.
 
I use a 1000w mains wet/dry vacuum that works great. I don't think the suck on a 90W vacuum would do much at all.

To be fair it was mildly useful for clearing up after drilling holes etc.
For instance when removing balsa from the core of a deck to add cleats.
 
I also had a rechargeable and 12VDC vacuum cleaner that worked and very light stuff but not very well so I got a small mains wet/dry that is much better as I has much more power for "real" work that I needed
 
Top tip for liquid in bilges.
Kiddies water pump they use to fire water at each other in the swimming pool. Will suck up water / oil from hard to reach places. Just suck it up and eject into conveniently placed bucket. Cheap as chips and easily replaced.
 
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