Piramic

In his scenario weight was a factor.

They were trying to get the sub to be as light as possible so it could be operated from nearly any vessel. The goal was to have the sub and a launch sled that could be launched and recovered aboard a rented ship. This was all to save money; they didn't want to have to purchase and outfit a special purpose support vessel.

I read Recursion a while back, it was a really strange book. I had to re-read the last parts to get a decent grasp of what was going on at the end.