This is about this question:

How might one guesstimate the "true" odds at Fort Donelson? [closed]

I'll concede that the title is somewhat broad. But I did my best to suggest objective, factual methods of answering it that can follow formulas actually in use.

  • Suggestion 1: How many "extra" men were there on the gunboats that were assisting Grant, but technically not under his direct command?

    This is a matter of record, except that I don't have access to these records.

  • Suggestion 2: Instead of comparing "men," compare the firepower of the guns on the gunboats versus that of Grant's 24,000 infantry.

    Someone at West Point or Annapolis would probably know the answer to this question.

  • Suggestion 3: Estimate the value of artillery as a force multiplier. This is a bit more subjective than the first two, but war game makers do this from time to time. That is, they create rules like:

    "Artillery increases the attackers' odds from one to one to two to one. Air power increases them to four to one."

    While these are necessarily "guesstimates," they are grounded in historical records. At the highest level, the Pentagon has powerful simulators for war games.

  • Suggestion 4 was just a "catchall" so I won't discuss it further.

And the question was not "What are the true odds…" (an opinion) but "How do people guesstimate the "true" odds…?" (factual).

The people mentioned above who are tasked with making these guesstimates could all give you factual, objective answers about what they do.

So why would my question be considered opinion based?

  • 1
    It seems like upvoted comment attached to the question answers this question.
    – T.E.D. Mod
    Oct 12, 2021 at 12:53
  • 1
    If it is possible to discuss two answers, it is subjective. If answer 1 says the ratio is two to one and answer 2 says the ratio is five to one, that will ge erate discussion, not an authoritative answer.
    – MCW Mod
    Oct 12, 2021 at 13:29
  • 1
    Why is this question considered opinion based? [...] How might one guesstimate [...] - Seems self-explanatory.
    – Lucian
    Oct 19, 2021 at 11:24
  • @Lucian: "Guesstimates" are used in military operations sometimes. For instance, there is a military axiom that an attacker needs a three to one (numerical) superiority to capture a fort (a guesstimate). Grant had 3 to 2. So did the gunboats provide a force multiplier of 2 to get him to 3 to 1 (answers are likely taught in the military academies. Simpler formulas: Did the men on the gunboats bring Grant's strength up to 3 to 1? Did the gunboats' cannon added to Grant's cannon divided by the Confederate's cannon amount to 3 to 1. The answers to the latter questions are part of the "record."
    – Tom Au
    Oct 19, 2021 at 13:02
  • @MCW: See my reply to Lucian. If e.g. the ratio of land plus gunboat-based manpower yields Grant a 2 to 1 advantage but the ratio of cannon yields him a 5 to 1 advantage, you get two different but (IMHO) "authoritative" answers that are useful in explaining the situation. Military issues are clouded with the "fog of war," and one will do well to "ballpark" them.
    – Tom Au
    Oct 19, 2021 at 13:07
  • @TomAu: This is neither a military site, nor an equation solving one. To keep the question historical, try perhaps rephrasing it as what guesstimates, if any, were either prepared beforehand, justifying the aggression, or afterwards, justifying the defenders' failure to keep it, and/or praising the assailants' bravery in storming it; or what scholarly (per the militarily-accepted methods you've mentioned) resources, if any, are there, discussing this particular aspect of the aforementioned battle.
    – Lucian
    Oct 19, 2021 at 14:37

1 Answer 1


With Grant leading the assault force, a rarity of competence among the generals on both sides: 100% chance of falling on the 16th or perhaps 17th.

With 16,000 men to defend a roughly 2 mile defensive perimeter, the Confederates were fielding 8000 men per mile. Despite numbers seemingly prophetic of World War 1 the fort succumbed on the second day of assault.

The truth is that Fort Donelson was woefully unprepared for an overland assault; doomed to fall quickly to any competent, determined, and aggressive assault. Think Singapore in February 1942. There was no fallback position from the outer perimeter except retreat into the fort proper combined with surrender (or as attempted unsuccessfully, breakout) by 80% of the defensive force; but even that buys only a few extra days.

General Simon Bolivar Buckner, however, argued that they were in a desperate position that was getting worse with the arrival of Union reinforcements. At their final council of war in the Dover Hotel at 1:30 a.m. on February 16, Buckner stated that if C.F. Smith attacked again, he could only hold for thirty minutes, and he estimated that the cost of defending the fort would be as high as a seventy-five percent casualty rate. Buckner's position finally carried the meeting. Any large-scale escape would be difficult. Most of the river transports were currently transporting wounded men to Nashville and would not return in time to evacuate the command.

A properly prepared fort holds out for months instead of hours, as Mantua in 1796 (7 months), Genoa in 1800 (2 months), Mafeking in 1899-1900 (7 months), or Tobruk in 1941 (8 months). Note that the number of defenders above for all but Mafeking is not far off the 16,000 at Donelson: Mantua 16,000; Genoa 11,000; Tobruk 27,000

enter image description here

All meaningful The land-facing defense of Donelson was encompassed in the assumption that Fort Henry wouldn't fall; with Henry itself having little in the way of land-facing defense. Although the Union wasn't big on that sort of thing: any Union commander at Fort Henry who didn't promptly capture Fort Donelson would have deserved court martial for cowardice in the face of the enemy.

  • 3
    I re-asked the question as "What made Fort Donelson peculiarly vulnerable to capture?" and suggest that you transfer your excellent answer to the new post, where it will get the attention it deserves.
    – Tom Au
    Oct 12, 2021 at 15:57
  • 2
    Ahm, is this answering this metaQ, or the one on main? Oct 12, 2021 at 17:59

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .