What would be the longest hypothetical emergency which would confine the Apollo astronauts to their suits?

Question

This answer poses the possibility of an emergency that would require Apollo astronauts to spend the rest of the mission in their suits:

A hole in the CSM might be more of an issue, since large portions of the pressure vessel are inaccessible during flight. If such an inacessible hole happened, it's likely the crew would have gone to suits, on umbilicals, and taken the very next opportunity to aim for Earth.

At what phase of the mission would such an emergency occur that would maximize the amount of time that the Apollo astronauts would need to spend in their suits?

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Update:

There briefly was an answer (deleted by its own author) about how running out of supplies would be a limiting factor. True, but that's not how I've asked to approach the question ("what phase of the mission..."). Therefore, I've added the trajectory tag.

I had previously said that "Whatever Apollo 13 did" is not a satisfactory answer. My chief concern is that an acceptable answer is backed up by some sort of analysis, and not just idle speculation. You can do the calculations yourself (as in PearsonArtPhoto's answer), or you can cite NASA documentation, just as long as someone has run the numbers. However, if you're going to use a quote from Jim Lovell or Gene Kranz, then you ought to show that they were citing actual analysis rather than making a (very) educated guess.

Will the Apollo 13 scenario end up being the answer? My gut-level feeling is that it will be very close to the worst case, but that there still is an even longer scenario.

Answer 1

Let's think this through. Some potential scenarios:

1. The service module to rupture at the same time as the CM. It seems unlikely that anything that killed a service module could have been survivable from reentry that also caused a puncture, but... The worst case for this scenario is probably near that of Apollo 13, a few hours extra. Apollo 13 was about 87 hours from the incident to landing, so let's say 92 or so is the max.
2. Astronauts on the Moon, hole appears in CSM. The crew would have to leave the lunar surface, dock, and then return to Earth. I can't find an exact time, but let's assume at least 2 hours to get from an EVA back to the command module. Let's say another 3 hours to prep for ascent (Including waiting for the right time). Apollo 11 took 5 hours from launch to discarding the ascent stage. Then another hour to line up and prepare for the return to Earth, and 60 hours to return to Earth, for a total of 70 hours
3. Something happened near the beginning of the mission, just after TLI. With the main engine working, they could actually turn the craft around using just the main CSM engine, and thus it wouldn't be a significant amount of time. If for some reason that wasn't an option, the time would be much larger, maybe around 120 hours. But that could only happen if the debris event also happened at the same time as a failure to separate, and failures to separate spacecraft are very rare. I can only think of one in recent history, Zuma, and that was likely because it was a one off test.

So I know you don't like the Apollo 13 answer, but that is actually fairly close to the worst case scenario. A worse case of a truly diabolical situation could have lasted as long as 120 hours. But more realistically I would say 70 hours or so.