Unlike the well-known furry variety, USS Constitution‘s many mouses are lumps of line and canvas built up on the outside of the diagonal stays that run between the masts. The mouse prevents the stay, which is looped around the mast and secured with an eye splice, from tightening up on itself. In Constitution‘s 1992-1996 restoration, several mouses were re-introduced to the stays between the masts. The Naval History & Heritage Command Detachment Boston riggers followed late 18th and early 19th century rigging techniques to “raise” each mouse. The Young Sea Officer’s Sheet Anchor by Darcy Lever, originally published in England in 1808, was used as a guide to re-create the rigging mouses needed to secure the diagonal stays between the masts.


Illustrations on page 10 of  The Young Sea Officer’s Sheet Anchor…, by Darcy Lever. Fig. 83 shows a mouse with the exterior lines ready for weaving.

 

Charles Ware’s 1817 sail plan of Constitution clearly shows mouses on the stays between the masts.

Sail Plan for the U.S.S. Constitution, 19-4-43 Record Group 19 [Courtesy National Archives and Records Administration]
Sail Plan for the USS Constitution, 19-4-43 Record Group 19. The red arrows point to where the mouses can be seen in the rigging on the forestays down to the bowsprit, and the mainstays between the main and fore masts. [Courtesy National Archives and Records Administration]

By the end of the 19th century, Constitution‘s standing rigging was wire rope and did not require mouses. The wire rope was spliced back in on itself to create the loops needed to go around the masts.

In the re-rig of the 1927-1931 restoration, natural hemp fiber was used for the standing rigging. The Navy Yard riggers again did not use mouses. Instead they spliced the hemp to make the loops, similar to the way it would have been done with wire rope in the late 19th century. It is likely that the 1930 Navy Yard riggers were more familiar with splicing wire rope than hemp. Therefore, when it came time to make up Constitution‘s standing rigging, they spliced the hemp as if it were the more familiar wire rope.

Raising a Mouse

Since the 1992-1996 restoration, when the standing rigging was changed to spun polyester, the diagonal stays between the masts have carried mouses. The mouses have short lifespans as the pressure of the eye splices causes them to collapse over time. The mouse on the mizzen preventer stay required full replacement during the 2015-2017 restoration.

NHHC Detachment Boston riggers Ryan Whitehead, Jose Hernandez-Juviel, and Timothy Burns worked in raising the new mouse on the stay in the rigging loft of Building 24 in the Charlestown Navy Yard. The mouse was completed in May 2016 and installed on the ship in June. The photo series below shows each major step in the process.

 

[Courtesy Naval History & Heritage Command Detachment Boston]
A mouse constructed in the early 2000s for the mizzen preventer stay shows signs of collapse. [Courtesy Naval History & Heritage Command Detachment Boston]

[Courtesy Naval History & Heritage Command Detachment Boston]
The woven polyester cover is removed to expose layers of tarred manilla line and rotten canvas, which must also be removed. [Courtesy Naval History & Heritage Command Detachment Boston]

[Courtesy Naval History & Heritage Command Detachment Boston]
All the layers of canvas and manilla line are removed to expose the wrapped polyester rigging. [Courtesy Naval History & Heritage Command Detachment Boston]

[Courtesy Naval History & Heritage Command Detachment Boston]
The mouse is made of alternating layers of parallel polyester twine wrapped in canvas and 1/4 inch polyester line. In this photo, NHHC riggers use a serving mallet to apply the first layer of 1/4 inch line. [Courtesy Naval History & Heritage Command Detachment Boston]

[Courtesy Naval History & Heritage Command Detachment Boston]
The finished first layer of the wrapped, or served, 1/4 inch line. [Courtesy Naval History & Heritage Command Detachment Boston]

[Courtesy Naval History & Heritage Command Detachment Boston]
A layer of canvas is applied to the first layer of 1/4 inch line. [Courtesy Naval History & Heritage Command Detachment Boston]

[Courtesy Naval History & Heritage Command Detachment Boston]
Polyester twine strands are laid parallel over the new canvas layer. [Courtesy Naval History & Heritage Command Detachment Boston]

[Courtesy Naval History & Heritage Command Detachment Boston]
The rigger continues to wrap layers of 1/4 inch line over the previous canvas and polyester twine layers. [Courtesy Naval History & Heritage Command Detachment Boston]

[Courtesy Naval History & Heritage Command Detachment Boston]
As the layers increase, the rigger uses a serving paddle to tightly wrap the 1/4 inch line around the canvas layer. [Courtesy Naval History & Heritage Command Detachment Boston]

 

[Courtesy Naval History & Heritage Command Detachment Boston]
In order to create the tapered shape, more layers of twine, canvas, and 1/4 inch line are added to build up the bottom of the mouse. The old mouse cover can be seen on the floor below. [Courtesy Naval History & Heritage Command Detachment Boston]

[Courtesy Naval History & Heritage Command Detachment Boston]
After the mouse has taken shape, the riggers begin grafting the thicker outer lines to create the exterior basket weave covering. [Courtesy Naval History & Heritage Command Detachment Boston]

[Courtesy Naval History & Heritage Command Detachment Boston]
The preventer stay is hoisted upright so the riggers can stand and weave the outer lines over the mouse. Note the new beige leather chafing gear that have been stitched to the stay. [Courtesy Naval History & Heritage Command Detachment Boston]

[Courtesy Naval History & Heritage Command Detachment Boston]
A close up of the mouse as the exterior cover is woven and begins to take shape. [Courtesy Naval History & Heritage Command Detachment Boston]

[Courtesy Naval History & Heritage Command Detachment Boston]
At the end of the weaving process, the mouse is completely covered. [Courtesy Naval History & Heritage Command Detachment Boston]

 

[Courtesy Naval History & Heritage Command Detachment Boston]
Once the mouse is complete, the riggers test its position on the stay to make sure it properly holds the eye splice. This mouse successfully prevents the loop of the stay from tightening up on itself. [Courtesy Naval History & Heritage Command Detachment Boston]

[Courtesy Naval History & Heritage Command Detachment Boston]
Two mouses are visible on Constitution‘s lower mizzen mast stays. The top mouse is the new one raised on the preventer stay during the 2015-2017 restoration. [Courtesy Naval History & Heritage Command Detachment Boston]
The new mouse should last several years, but will likely need replacement before Constitution‘s next dry docking in approximately 20 years. Next time you visit Constitution and look up in the rigging, try to spot a mouse!

– M. M. Desy & K. Monea

 

_____

The activity that is the subject of this blog article has been financed in part with Federal funds from the National Maritime Heritage Grant program, administered by the National Park Service, U.S. Department of the Interior, through the Massachusetts Historical Commission, Secretary of the Commonwealth William Francis Galvin, Chairman. However, the contents and opinions do not necessarily reflect the views or policies of the Department of the Interior, or the Massachusetts Historical Commission, nor does the mention of trade names or commercial products constitute endorsement or recommendation by the Department of the Interior, or the Massachusetts Historical Commission.

The Author(s)

USS Constitution Museum