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Open Year-Round 9:30 to 5.

No. 35: Measuring Up: Gauges, Indicators & Scales

The maritime world has been dutifully measuring itself since the Ark was recorded at 300 cubits length over all, 50 cubits beam, and 30 cubits overall height. A deadweight tonnage could likely be determined, if we could agree on a conversion for cubits and how many animals actually made it aboard, their weight and the weight of their fodder, family victuals, etc.

The usual purpose of such measurements has been to levy the tariffs, taxes, duties, and premiums beloved of customs inspectors and marine insurance underwriters, but somehow they weren't around to hit old Noah up when he finally made port. Since then, the numbers have crept into maritime life in Biblical proportions.


Here are a few measuring devices employed in Maine's maritime history.

If the Ark had pulled into Bath, Maine in the 19th century, Noah would have had to report to the large granite U.S. Customs office building, that still looks out over the Kennebec River on Front St.

Depending on his paperwork, Noah would then have been escorted back out to his vessel by an agent or two who would be very interested in measuring a variety of internal volumes aboard. This calibrated sliding measuring stick is what they might have used. It is but one of several such, in various lengths, that MMM acquired after the Bath office was consolidated with Portland as foreign shipping landings on the Kennebec grew non-existent.


Each such measuring instrument has a 5-figure government registration number, in odd contrast to the humble nature of the handmade device and its basic scale, that would  simply round up or down to the nearest inch.


By 1790, the maritime service known originally as the Revenue Marine had been established by the fledgling U.S. government, ostensibly to reduce smuggling, but also to enforce tariffs. Alcoholic imports were 'proofed' by inspectors aboard patrolling Revenue cutters, using hydrometers like this one.

The contoured, chamois-skin -lined case protects the vial for the liquid being sampled and the glass instrument that was floated within.  The scale has been hand lettered; the manual of reference tables is dated to 1849.


From the engine room of the 1884 steam tug SEGUIN, this register recorded the engine revolutions. This straight totaling (not revolutions per minute) worked for the slower speeds of steam equipment. And, unlike more modern gauges, there was no need to squint at the numbers; the adjacent coin in the image is a quarter, which scales this lovingly polished device to about dinner plate size.


A bit smaller and a bit less polished, but possibly more crucial is this steam pressure gauge. Woe betide the engineer who neglected or ignored such a measurement. The Crosby Steam Gage and Valve Co., Boston, est. 1875, was a major purveyor of steam components for both the maritime and railway industries.
Found in the basement of a local house, the gauge's faceplate has been customized to reference an unknown steam pressure device built by, or at least assembled by Bath Iron Works, our local shipyard. Still in business here in Bath, BIW now installs engine room gauges that are way high tech, entirely digital, and never need polishing.

Except for their loose wrenches sliding by, the engine room gang would not really take note of how far the ship was rolling, but those up on the bridge would take considerable interest. This 1920 Henschel clinometer ambitiously records up to a 70-degree roll; the two reset-able outer needles record the extremity of motion, should the vessel actually recover.

Ships pitch as well as roll, but this McNab 'Pitchometer' is instead for determining the pitch of a boat's propeller - how aggressively the lead edge of the prop blades grab at the water. The heavily built brass gauge has a small spirit level behind the tightening wheel, and adjusting arms to conform to the complex geometry of the propeller being measured. Unfortunately, the user manual is missing. The McNab Co. of Bridgeport, Connecticut also held the U.S. license for the now almost-forgotten Kitchen reversing rudder, patented in England in 1916.

A 1937 Gray Marine Motor Co. pocket calculator to determine the speed-slip of a boat for any given RPM and propeller pitch, possibly a boat-show freebie.
 

A London made 1854 Edward Massey taffrail log. Despite the elegant script engraved in the brass, this bit of clockwork was meant to be shackled to a line and committed to the deep. The copper helix would begin to spin and wind the gears calibrated within the triangular housing to record the distance traveled. The 'log', as it was traditionally called, was read by retrieving it from the water and swiveling open the protective lid to view the three dials indicating the half mile, miles and tens of miles of the day's run. After 1878, the arrangement was improved to allow the dials to remain aboard at the stern rail, connected to the submerged helix by a flexible rotating cable.

Ensconced in this varnished mahogany case is a steam engine indicator, a crucial tool for any mechanic, technician, engineer or inspector involved with steam power. 
 Mounted on the engine, pressure and cylinder stroke were recorded onto a paper card wrapped around the device, upon which an arm traced a diagram. Here is a typical example:

From the appearance of the elongated loop, which shows the drop in pressure over the stroke length of the piston, the valves can be adjusted to maximize the efficiency of the engine (pump, winch, locomotive, etc.), letting in maximum pressure just as the piston returns.

The appearance of the Philips' Planisphere star plotter has changed only slightly since the 1850's; this one could be anywhere between 1870 and 1930. Of course, with the exception of a few newly discovered planets, the heavens themselves have remained virtually unchanged for navigators through the ages, so the Philipses, father and son and their successors, deal in content with an eternal shelf life. The current design is now printed on more durable plastic, but lacks the distinctive tooled leather and gilt lettering of its predecessors.


Back down to earth for a standard far from fixed: three sawyer's scale sticks from the Maine woods.

Top- out of Milo Junction, a Valentine Fabian & Son Maine or Holland Rule;

Middle -out of Bangor, a Snow & Neally International Log Rule; 

Bottom - a board footage scale for already dimensionally sawn lumber.

A careful (squinted) comparison of the top two rules along the 12 foot log length row reveals the dilemma of  the diverging scales, starting at the 7 inch diameter mark, when the Holland rule jumps to 23 board feet coming out of the same log that under the International Rule yields 20 board feet. Akin to the railroad gauge wars, various other Rules were to be hashed over in Maine, including the Doyle Rule, the Scribner Rule, the Saco River Rule, and the Bangor Rule. State legislation finally settled on the International Rule in 1906.

A selection of net maker's mesh gauges or 'boards'; the larger two have been stamped with their circumferences. By extension, this figure will be the measurement of the mesh openings of the net when pulled closed corner to corner. These boards were carefully fashioned and polished out of the hardest woods available, sometimes even ivory, to smoothly assist the repetitive knotting process, and to resist the wear of the twine as thousands of knots were tied. If the mesh board wore, the net's gauge would become smaller, which could cause problems when the warden checked up on your shrimp net.

Finally, two measuring devices near and dear to our hearts, or, should I say, stomachs. (Left)  A lobster carapace length gauge to determine if it's a keeper. Current legal length is now slightly longer: 3-8/32", with an upper limit of 5" as well, which is why present day lobster gauges are two sided. (Right) A soft shell (steamer) clam ring with the two inch minimum shell size (at widest diameter). Up to 10% of a sampled pile of clams can be under this size.

Maine Dept. of Marine Resources

Let me know if you stopped by down here!
Thanks,
Chris Hall, Curator of Exhibits 

Artifact Donors, in order of appearance:


U.S. Customs measurer  76.76.5  Bath Customs House salvage 
U.S. Revenue Service hydrometer 67.2307  Stephen K. Crosby
engine register 69.3472,349 Clyde B. Holmes, Jr.
steam gauge 75.74.1 Robert Ingersoll
clinometer 73.236.2 Henschel Corp
pitchometer 2007.66 Richard Lagner
speed-slip calculator  92.65.12 Howard Whalin
patent log 85.120 Museum purchase
steam engine indicator  68.2744  Irma L. Sawyer
planisphere 71.164.9 Richard F. Sewall
log scale 69.3461.8 MMM Burden Collection
log scale 71.282.1 MMM Burden Collection
board scale U569 Anonymous
mesh boards 90.119.1 MMM Burden Collection
lobster gauge 85.57.1 Museum purchase
clam ring 92.37.3 Top-Me Products

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Maine Maritime Museum

243 Washington Street
Bath, Maine 04530