Concerning the US Model 1852 Navy Officer's Swords and later variants -
To my knowledge there have been no official changes to regulations specifying the width, curve, or weight of the US Model
1852 Navy Officer's Sword. Although we see the earlier swords as being "combat worthy" with heavier blades, that was
simply a sign of the times when swords were intended to be effectively used in combat. The American Civil War changed all
that. I do know that many subtle changes have been made but not specified by regulation(s). In 1850, 1872, and again in 1902
several US military sword patterns were changed and some eventually adopted. It is quite odd that the US Model 1860 Staff
and Field Officer's Sword (for all Army Officer's) was not officially adopted until 1872 and became mandatory at that point
(only cavalry and artillery patterns were different). The adoption of the smaller lighter (and virtually useless) US Model
1872 Cavalry Officer's pattern seems to have been the beginning of the lighter more ceremonial/symbolic blades; everything
changed once again in 1902, the only exception being the Navy and related services.
The only Navy regulation(s) I have ever seen - related to swords - simply state:
1797 - CAPTAINS, LIEUTENANTS, AND MARINE OFFICERS, to wear when full dressed, cocked hats, with black cockades, and small swords (yellow mounted) and when undressed, such swords as may be hereafter fixed upon or ordered, which said swords are to be worn at all times by the midshipmen, who are to wear cocked hats, &c. when fully dressed only-- surgeons; mates, sailing masters, and pursers, cocked hats and black cockades.
1802 - CAPTAINS AND LIEUTENANTS, when in full dress, to wear shoes, buckles, small swords, and gold laced cocked hats; the lace not to shew more than three quarters of an inch on each side--in undress to wear hangers.
1814 - Captains and Lieutenants, when in full dress, to wear half boots, cut and thrust swords with yellow mountings, and gold laced cocked hats; the lace not to show more than three-quarters of an inch on each side.
1833 - No mention of sword(s).
1841 - The swords are to be cut and thrust; the blade to be not less than twenty-six inches long, and not less than one inch wide at the hilt. The belt must be made with a frog, so as to wear the sword perpendicular; grip to be of white, scabbard to be of black leather, mountings to be of yellow gilt. Belts for undress to be of black leather; for full dress, the belts to be of white webbing, both to be one and a half inche wide; the mountings must be yellow gilt. The swords and mountings, and the mountings of the belt, to be according to pattern. Belts shall be worn under the vest. Swords are always to be worn with uniform, when absent from the ship on duty, or when on leave upon foreign stations.
1852 - For all Officers--shall be cut and thrust blade, not less than twenty-six nor more than twenty-nine inches long, half basket hilt, grip white: Scabbards of black leather. Mountings of gilt; and all as per pattern [by supplied drawing of the hilt].
1864 - For all officers, shall be a cut-and-thrust blade, not less than twenty-six nor more than twenty-nine inches long; half-basket hilt; grip white. Scabbards of black leather; mounting of yellow gilt.
Present - Officers...shall have a cut and thrust blade, from 22 inches to 36 inches long, half basket hilt, and fit in a scabbard of plain black grain leather or synthetic material presenting the leather appearance.
It is also generally accepted that the "regulation sword length for an individual is determined with the sword at the carry position. The tip of the blade will fall not more than one inch above or below eye level."
It should be noted that the US Revenue Cutter Service Officer's Sword was a smaller,
straight-bladed sword - otherwise virtually identical to the US Navy Model 1852 - adopted
sometime between 1889 and 1896; it is my belief this sword was copied by the various makers
supplying both branches of service. There is no official record in Navy Uniform Regulations
specifying a lighter-straighter sword to the best of my knowledge. The last regulation specifying
a blade width was the regulation of 1841 when it clearly stated "not less than one inch wide at the hilt."
The next regulation (1852) failed to include a blade width specification.
One must also bear in mind, all officer's swords - save a few - were privately purchased by the officer or
officer's agent(s) [family, friends, etc.] and did not require Government inspection.
Additionally, although the Navy Officer's Sword hilt was been clearly specified in regulations
- by drawing - the blade (except for length) has never been specified except as noted above (with the exception
of the regulation in existence between 1841 and 1852).
Having said all that, it is generally accepted that US Model 1852 Navy Officer's Sword blades - from about 1852 to about
1872 - were heavier and apparently made with combat in mind. Blade dimensions during that time period were ~32" in length,
~1-1/16" wide at the blade flat (ricasso) near the hilt, and ~1/4" thick; after about 1872, they
became more ceremonial, blade dimensions were ~30" in length, ~3/4" wide at the blade flat (ricasso) near the hilt,
and ~3/16" thick.