An overweight spaceship (or OWSS for short) is a would-be spaceship similar to the lightweight spaceship, middleweight spaceship and heavyweight spaceship, but longer. On its own an overweight spaceship is unstable. While the latter two xWSSes produce belly sparks that would die off, an overweight spaceship produces an egg that does not vanish but interferes with the body.
Nonetheless, an overweight spaceship can be escorted by true spaceships to form a flotilla. For an OWSS with top "spark" length over 4, minimal escort size difference is 4, as shown on the left. It is also possible to stabilize the OWSS with more OWSSes, which then have to be stabilized by more xWSSes.
Many lengths of overweight spaceship can be constructed by means of glider synthesis. Recent syntheses are collected in the xq4 synthesis listed in Catagolue; a number of older recipes can be found in Mark Niemiec's synthesis database.
In other rules
The non-totalistic rule FattyLife (B3-n4nt5qr6i/S23) is specifically tailored to support the overweight spaceship with spark length 3, making it a p8 spaceship.
Overweight Spaceship with escort
Overweight spaceship supported by more overweight spaceships.