USS Constitution’s Main Mast Rig Repairs

The Naval History and Heritage Command (NHHC) Detachment Boston’s riggers are down-rigging USS Constitution’s main mast so that the ship’s main top mast (second section of the mast), main fighting top, and main channels can be removed for replacement and repairs. NHHC Detachment Boston is a civilian branch of the U.S. Navy located in the Charlestown Navy Yard and tasked with the ongoing care and preservation of USS Constitution.

The current main top mast was made in 2009 from laminated Douglas fir. At 64 feet, 10 inches long, the main top mast weighs 5,300 pounds. The new top mast will be manufactured by the Detachment Boston from laminated southern yellow pine.

The main fighting top was last removed for repairs in November 2008. It will be examined to determine if only repairs or a complete replacement of the top will be necessary. Each of Constitution’s three masts must be either partially or wholly down-rigged to facilitate removing the main top mast and the main fighting top.

A “top” on a vessel is the platform found approximately half-way up the mast. The top was important because it extended the top mast standing rigging shrouds athwartships, giving the top mast shrouds a greater angle to the mast which provided additional and necessary support for the top mast and the rig above.

On a warship like USS Constitution, the tops are known as “fighting tops.” The tops were battle stations for Marines and “riflemen” (crew trained to fire muskets and rifles), providing an elevated vantage from which they could fire at their opponents either in the enemy’s fighting tops or upon the officers and crew on the opposing warship’s spar deck.

Constitution’s main top is the largest of the three tops on the ship. It is 21 feet wide and 15 feet, 4 inches deep. It weighs 10,000 pounds. Because the main top is too big to be brought inside Building 24, the Detachment Boston’s preservation facility, it will be worked on under a large tent in front of the building.

While the main mast is down-rigged with just its lower mast remaining in place, the main channels will also be replaced. The “channels” on a vessel (sometimes also referred to as the “chains” or “chain-wales”) are platforms that project out from the sides of a sailing vessel’s upper hull. The channels allow for greater spread of the lower masts’ rigging, providing needed support to the lower masts.

Constitution is a “ship” by rig. A ship is a sailing vessel with a minimum of three masts (fore, main, and mizzen) and each mast has horizontal yards from which the square sails are set. The ship rig is the most complex sailing rig. The three masts and their components are connected to each other and are directly affected by work on any section of the three masts. Therefore, work on the main mast necessitates partial down-rigging of the fore and mizzen masts as well. The down-rigging began in late 2022 with the removal of most of Constitution’s running rigging attached to the yards. The uppermost standing rigging supporting the fore and mizzen topgallant/royal masts was removed so that these masts could be lowered, thereby freeing up the main topgallant/royal mast and main top mast to be down-rigged and removed.

Because all of the main mast standing rigging has to be removed to facilitate the removal of the main top mast and the main fighting top, the lower main mast will be supported, “stayed,” with temporary steel cables.

USS Constitution will be down-rigged through the rest of 2023. The new main top mast, the repaired or replaced main fighting top, and the new main channels will likely be installed on the ship by spring, 2024. Once the main fighting top is placed on the main mast, the upper masts, lower and upper standing rigging, yards, and running rigging taken off the main mast will be re-installed. The fore and mizzen masts will be re-rigged with their upper masts, yards, and standing and running rigging as well. Constitution’s three masts should be fully rigged for the summer of 2024.

The Author(s)

Margherita M. Desy
Historian, Naval History & Heritage Command

Margherita M. Desy is the Historian for USS Constitution at Naval History and Heritage Command Detachment Boston.