Artifact in Focus: The Mairi Bahn’s Compass

Let’s start with a bit of background information on the ship itself. The Mairi Bhan was a clipper built in Glasgow in 1874, and was called one of the most handsome ships in the Pacific by contemporary observers. The 230-foot-long ship spent much of her early career sailing across the world. By the turn of the century, the Mairi Bhan was sold to an Italian trade group that used it as a tramp freighter. It departed Genoa for Trinidad in early 1912 with a cargo of Italian wine, domestic goods and marble. After delivering her cargo safely on Trinidad, the ship took on a load of asphalt and headed west.

A day after departure, on December 7, 1912, the Mairi Bhan was caught in a storm and was blown off course towards Bonaire. During the storm, the asphalt started to shift in the hold, causing a dangerous situation whereby the ship started to list and ran the risk of capsizing. In an attempt to save his crew, the ship was intentionally run aground on Bonaire’s northwestern shore by Captain Luigi Razetto. The Captain and all crew members survived. The ship sat on the reef for several days, but on Christmas Day, it was reported that the Mairi Bhan had sunk in 30 feet of water and it was impossible to salvage the ship. Eventually, the majestic clipper slid further down the reef slope into deep water and came to rest on the sandy bottom.

Largely forgotten as time passed, the Mairi Bhan was rediscovered in 1968 at a depth of 200 feet and is now a popular site for technical diving. Over the years, numerous artifacts have been recovered from the wreck. Most recently, technical divers from Buddy Dive Center found the ship’s compass on the sandy bottom next to the wreck. After recovery and a lengthy conservation treatment, The Shipwreck Survey was asked to document the object.

The ship’s magnetic compass has been around in various forms for centuries. Since its development, ships have carried compasses to aid in navigation, especially when out of sight from land or at night. Ship’s compasses were often mounted on a binnacle, which is a stand or housing. The idea behind a binnacle is to counter the magnetic deviation caused by iron components of the ship so that the compass can point to magnetic north. On an iron-hulled vessel such as the Mairi Bahn, the binnacle would have been placed somewhere in the center of the ship. This would have minimized the effects of the magnetic properties of the iron vessel on the compass by placing it close to the magnetic center of the ship. It was likely placed close to the helm to allow the ship’s navigator to determine position and course. The compass contained a gimbal arrangement inside the binnacle to hold the compass card horizontal despite the motion of the ship. The compass was attached to the gimbal by small extensions on the side, two of which can be seen on the Mairi Bahn’s compass. It’s possible that the vessel carried multiple compasses. Ships were often fitted with a telltale compass as well. These were located in the Captain’s quarters, hanging above his bunk, so that he could see the course being steered without going on deck. If a telltale compass was used on the Mairi Bahn, it is probably hidden somewhere inside the ship.

We decided to enlist the help of talented archaeological illustrator Eric Stegmaier to make a reconstruction drawing of the compass and how it would have been placed on the ship. This is a great way of showing the original context of the object and it helps both researchers and the general public to understand how it was used.