Crane and Westmoreland provide the following criteria for a black hole useful for a spacecraft:

1. has a long enough lifespan to be useful,
2. is powerful enough to accelerate itself up to a reasonable fraction of the speed of light in a reasonable amount of time,
3. is smal l enough that we can access the energy to make it,
4. is large enough that we can focus the energy to make it,
5. has mass comparable to a starship.

We find that a black hole with a radius of a few attometers at least roughly meets the list of criteria... Such BHs would have mass of the order of 1,000,000 tonnes, and lifetimes ranging from decades to centuries.

A BH with a life span on the order of a century would emit enough energy to accelerate itself to relativistic velocity in a period of decades. If we could let it get smaller and hotter before feeding matter into it, we could get a better performance.

A SBH with a radius of 0.9 attometers has a mass of about 606,000 tonnes and a power output of about 160 petawatts. Over a period of only 20 days a 160 petawatt power source emits enough energy to accelerate 606,000 tonnes up to about 10% the speed of light.

The upshot is that SBHs with effective radii between roughly 1 and 6 at- tometers could be adequate power sources for starship propulsion systems - if their power can be harnessed efficiently. The smaller the BH, the more powerful it is. However, one must either be able to arrive at one’s destination before the BH evaporates completely or one must be able to feed the BH in such a way as to prolong its life. In the most optimistic scenario, where one can feed the SBH very efficiently, one could have very capable manned starships driven by extremely powerful SBHs with radii smaller than our suggested range of 1 to 6 attometers.

In his 1983 novel Lifeprobe, Michael McCollum uses the idea of a nuclear fusion drive that makes use of an antimatter mini-black hole.

In a series of novels starting with the 1989 work The Founder, Christopher Rowley mentions a FTL propulsion method called the Fuhl drive. It uses miniature black holes trapped in a magnetic container, which are then spun together in patterns that drop the starship into and out of hyperspace.

The earliest use that I know of for this idea in sf is in Arthur C. Clarke's 1976 novel Imperial Earth:

"D'you see that pipe? said the engineer. "The small red one?... That's the main hydrogen feed.. All of a hundred grams a second. Say eight tons a day, under full thrust.":

They were now hovering beside a massive - yet still surprisingly small - cylinder that might have been the barrel of a twentieth-century naval gun. So this was the reaction chamber of the Drive...

Near the middle of the five-meter-long tube a small section of the casing had been removed, like the door of some miniature bank vault, and replaced by a crystal window... a microscope... was aimed into the interior of the drive unit.

Duncan floated to the eyepiece and fastened himself rather clumsily in place.

"Look at the crossover at the exact center," said his guide.

Duncan obeyed... then he realized that a tiny bulge was creeping along the hairline as he tracked the microscope. It was as if he was looking at the reticule through a sheet of glass with one minute bubble or imperfection in it.

[It's] like a pinhead-sized lens. Without the grid, you'd never see it."

"Pinhead-sized! That's an exaggeration if ever I heard one. The node's smaller than an atomic nucleus. You're not actually seeing it, of course - only the distortion it produces."
(Read more about Clarke's Asymptotic drive