sci.military.naval FAQ, Part H
Age of Sail & Historic Ships

Revised 30 March 2000
Version 1.51
Compiled and Maintained by: Andrew Toppan
SMN FAQ Main Page:

Contents of this section:
Section H.1: What is hogging?
Section H.2: Status, condition and restoration of USS Constitution
Section H.3: Controversy about the history of the frigate/sloop-of-war USS Constellation
Section H.4: Restoration of the Sloop-of-War USS Constellation
Section H.5: Sailing Ship Rig Types & Classifications

Section H.1: What is hogging?

The terms "hogging", "hogged" and "hog" refer to the sagging of the bow and sterm of a ship relative to its midships section. A ship that has experienced hogging is said to be hogged. Instead of showing a flat, level hull line, a hogged ship is "curved", with the bow and stern lower than the center of the ship.

Hogging is generally found in older wooden vessels, due to the natural weaknesses in their structure. However, a small degree of hog is not unheard of in iron and steel ships. Hogging occurs because the bow and stern of the ship, while carrying a considerable amount of heavy equipment, posses relatively little buoyancy. The center of the ship, on the other hand, possesses a great deal of bouyancy and may be quite light-weight if the ship is not loaded with heavy cargo or ballast. This unequal distribution of forces, with great weights but little buoyancy fore and aft, and little weight but great buoyancy amidships, leads to deformation of the hull.

Section H.2: Status, condition and restoration of USS Constitution

USS Constitution is the oldest commissioned warship in the US Navy, and the oldest warship afloat in the world. Constitution was commissioned in 1798, first putting to sea 23 July 1798. She was one of six frigates authorized by Congress in 1794. She is known as "Old Ironsides" because cannonballs were once seen to bounce off her hull.

Constitution was designated as an "unclassified" ship (IX) in 1920, being numbered IX 21 on 8 Dec 1941. The desigation IX 21 was withdrawn on 1 Sept 1975 because it tended to "demean and degrade" Constitution through association with the other IX craft, a group of barges, hulks, test vessels and other miscellaneous equipment. She is now identified as "ex-IX 21". Constitution was renamed Old Constitution 1 Dec 1917 to clear her original name for a new battlecruiser. The battlecruiser was cancelled and Constition was restored to her original name 4 July 1925. The ship has been berthed at Boston since 7 May 1934. Until 1997, no sails had been been fitted since that time.

Constitution was rebuilt and modified several times while in service, and has been "restored" several times. The restorations frequently made errors because there were no original plans available. Some structural parts were left out because everyone assumed she would never sail again, so it was assumed that she wouldn't need as much strength as had been built into her originally. Unfortunately the omission of those structural parts lead to deformation of the hull while she was tied up as a musuem ship.

By 1990 Constitution was in need of another restoration. She had "hogged" considerably (bow and stern sagged), and her general condition indicated the need for drydocking and major restoration work. Therefore, at the end of the Sail Boston '92 "tall ships" event, she was stripped and drydocked. The objective of the restoration was to restore her to her 1812-era condition and configuration. Plans for her sistership President were obtained from the Royal Maritime Museum at Greenwich, England; they had been drawn up after President was captured by the Royal Navy. The plans were used to ensure that she was restored as accurately as possible.

All rigging, spars, ballast, guns, non-structural interior items, etc. were removed before reconstruction began. All structural members deleted during previous restorations were restored, and she was restored to "sailable" condition, but plans did not include fitting her with sails. Measures were taken to keep her from drying out while in drydock--the hull was draped with canvas to keep moist air in and to keep the sun out, and several inches of water were kept in the bottom of the drydock, to keep everything moist. Specialists in wooden ship restoration were imported from other museums and ship restoration operations.

Structurally, the restoration replaced all deteriorated wood, replaced virtually all of the knees, added considerable structural bracing (knees, diagonals, etc.), and replaced all cracked or weakened metal fittings. Most of the wood used was live oak felled by hurricane Hugo. The Navy sent teams out into the forests after the storm, templates in hand. Pieces that matched the templates were shipped to Boston for use in the restoration. A considerable supply of surplus oak was stored against future requirements. The structural improvements should retard future hogging.

The hull was entirely recaulked and recoppered. She has received all new laminated spars, designed to last longer than previous built-up spars. All new rigging has been fitted; all interior bulkheads, fancy work and other non-structural items have been replaced or refurbished. New lighting and fire protection systems have been installed; they are considerably less ugly than the old systems. She was refloated 26 Sept 1995; fitting out continued well into 1996.

Much of her hull structure is still original. The keel, keelsons, stem, sternpost, and many ribs and planks are original. The keel is believed to have at least another 100 years off life left in it. Virtually all of her metal fittings are original, including the bronze rods (forged by Paul Revere) that hold her hull together. The rods were examined by sonar during the restoration and the few cracked rods were replaced.

Although the Navy has not planned to sail her, there had been consistent suggestions that she be fitted with sails since it was announced that she would be restored to "sailable condition". Sailmakers offered free sails and the Coast Guard offered to train her crew aboard Eagle, but the Navy declined. It was thought that the possibility of damaging a priceless national treasure was simply too great. However, in late 1995 it was decided that she would be fitted with sails and would be sailed for the first time since the 1800's. The first canvas for her new sails was cut during summer 1996. At first she was only fitted with a few sails, but a full set of sails will be fitted as funds are available. The sails are to be paid for by a "penny drive" similar to the fundraising effort that paid for her initial restoration in the 1920's.

On July 8, 1997 Constitution was towed from her berth and taken several miles offshore, where her sails were set. All but one of the tugs cast off their lines, and the remaining tug allowed her towlines to go slack. Constitution then sailed under her own power, reaching approximately 6 knots. However, this was not officially considered a "sail" because the tug was still attached to Constitution.

On July 20, 1997 Constitution was towed from Boston to Marblehead. On the 21st she was towed out from Marblehead, the tugs were released, and she set her sails. She then sailed, under her own power and without any assistance, for the first time since the 1880's. The sail lasted approximately one hour.

Since then it has been proposed that she sail to various ports, including Gloucester and Portsmouth, NH. However, the Navy has announced that she will not leave the immediate area of Boston Harbor.

Section H.3: Controversy about the history of the frigate/sloop-of-war USS Constellation

The exact history and classification of the frigate or sloop-of-war USS Constellation often become issues.

The original Constellation was a frigate completed in 1797. She was one of the six frigates authorized in 1794; Constellation was one of the three 36-gun ships of the group (Constitution was one of the three 44-gun ships). Constellation was broken up in 1852 at Gosport (Norfolk), Virginia. In 1853-1855 a new 22-gun sloop-of-war was built at the same shipyard and given the name Constellation. As was common at the time, the new ship was built using funds appropriated for ship repair, rather than new-construction funds. To maintain the illusion that the ship had actually been "repaired" rather than built new, Navy records showed that the 1797 frigate had been "modified" to become the 1855 sloop-of-war. In reality the 1855 vessel was completely new, and was quite different from the 1797 vessel:

		1797                    1855
		====                    =====
Length          167 feet                179 feet
Spar Deck       partial (~40% open)     complete (100% decked over)
Gun Deck        partially open          completely closed
Guns            36+, spar and gun decks 22, on gun deck only
Stern           square                  rounded
Bulwarks        open (for gunports)     solid
Over the years the ship came to be one of the few remaining sailing vessels in the Navy. Because of the falsified records from the 1850's, the Navy treated her as if she was a 1790's frigate. She was designated IX 20 at the same time Constitution received her designation (see above). In 1955 she was donated to a preservation group in Baltimore, Maryland, where the 1797 frigate had been built. The group "restored" her to look like the 1797 ship by removing part of the spar deck, cutting holes in her bulkwarks, and adding guns on the spar deck. These changes contributed to her deterioration by reducing the strength of the hull, adding significant weight, and letting water in to the interior of the ship. The group steadfastly maintained that Constellation was the original 1797 ship, despite much evidence to the contrary.

In 1991 a US Navy study conclusively proved that the ship was not the original 1797 vessel. This fact has now been accepted, and the vessel has been restored to her 1855 form.

Section H.4: Restoration of the Sloop-of-War USS Constellation

In 1994 the Navy surveyed Constellation and found her to be in very poor condition. One officer reported that he could easily plunge his finger through some of her major beams, due to the advanced state of decay. Among other problems, she was leaking 1200 gallons a day and had suffered 35 inches of hog. She was promptly closed to the public, and all rigging and guns were removed. The frail hull was temporarily supported by a network of steel cables and slings to hold her in her proper shape until she could be drydocked.

The original museum group, which had been responsible for the "restoration" of the ship since 1995, was dissolved; the Constellation Foundation was formed to save the ship. The Foundation abandoned the claim that the ship was the 1797 frigate. This allowed them to promote the ship as "the last surviving ship of the Civil War" rather than having the ship seen as "just another 1797 frigate".

Constellation was moved from her berth to a shipyard on 17 November 1996; restoration started soon thereafter. The restoration work was completed in 1999. For more details and photos of the restoration, see

Section H.5: Sailing Ship Rig Types & Classifications

Sailing ship classifications can be confusing, as some designations refer to the rig (type of sails) carried by the ship, while others refer to the military role of the ship. The most common designations are as follows:

Back to the FAQ Archive Page

This FAQ created and maintained by Andrew Toppan
Copyright © 1997-2003, Andrew Toppan.
Reproduction, reuse, or distribution without permission is prohibited.