Ship Caulkers and Their Tools, by Sanford Moss

Volunteers at the New Bedford Whaling Museum perform myriad tasks in all of the departments of the institution.  One such individual, Sanford “Sandy” Moss, works in the Curatorial Department identifying and researching tools and related artifacts in our collection.  The article below is a piece he has penned on a simple looking tool box and its contents.  Through his specialized expertise and some additional research, he has been able to relate a good bit about the work and life of the unknown person who owned this tool kit.  This is but one example of how volunteers “bring history to life” through a labor of love.

The picture below shows a box of tools that belonged to an un-named ship caulker who doubtlessly worked in a crew of ship caulkers on the New Bedford waterfront, sometime in the late 19th or early 20th century.  As with most tool boxes, we can tell something of the man who owned this set of tools, and what he did for a living.

In the days of sail and Yankee whaling, ship caulkers were important shipyard workers, finishing the process of making new hulls and decks tight and leak-free; and restoring older hulls to the same the same degree of fitness prior to every extended whaling voyage.  Their job was one that required skill, but a fairly simple arsenal of tools.  These included two or three types of caulking mallets, a group of caulking “chisels” or “irons” that were really tampers, and a small array of hooks or narrow scrapers to clean the seams between the hull or deck planks prior to caulking.  The actual caulking material could be comprised of cotton yarn or string, and most importantly, oakum, which was usually the yarn from which manila or hemp cordage was made and tarred with pitch.


2001.100.3143: Leather seat with wood sides and bottom. Contains one caulking mallet, five caulking irons, one seam raker made from a race knife, one instrument (seam raker), and one spare mallet handle.

This next photograph shows men at work caulking and rigging the Bark Alice Knowles, getting her ready for an extended whaling voyage.

Caulkers at side of Bark Alice Knowles

Caulkers at side of Bark Alice Knowles

The first five men from the left of the picture are caulkers working on planks above the waterline on the bark.  The two men to the right appear to be riggers who are working at anchoring what are known as “chain plates”.  Chain plates are iron rods doubled back on each other that are fastened to multiple port and starboard stays that support the various masts on the vessel.  These riggers are working on the chain plates that will anchor the port stays supporting the main mast.  There is a lot going on in this picture, but first, let’s go back to that caulker’s tool box.

An obvious feature of this tool box is that it is fashioned as a seat, having a contoured leather top, with an opening that allows the tools to be accessed or stored as they are needed.  The opening also serves as a handle, so the caulker could easily carry the box from location to location on the job.  Ostensibly, the caulker could use his tool box as a seat while eating his lunch—but more importantly, he would use it when working on the bottom of a hull that had been hauled out of water, and was too close to the ground to allow him to stand comfortably (sometimes caulkers fixed “rocker bottoms” to their seat boxes, allowing them to rock backward when working overhead).  This feature suggests that the owner of this box likely worked on smaller vessels than the large whalers.  The larger vessels were generally careened or “hove down” while afloat at the wharves so that their bottoms could be exposed for maintenance work.  The caulkers then worked from rafts alongside the vessels, and did not need to work from under the bottom.

A second feature of this box is that the tools arrayed in front of it, are in nice condition.  The owner took good care of them.  Many caulking tools, exposed as they are to salt water and the elements while working outside, are often rusted, pitted, with the ends of the irons peened from hard use.  These are not in that condition, because their owner cleaned and oiled them regularly.  The tools include five “caulking irons” of only two types.  Four of these (the pointed ones) are known as “clearing” or “reefing” irons, though there is little uniformity in the names of caulking irons, as regional and local names can dominate.  For instance, these reefing irons are also known as “jerry” or “cape” irons.  Whatever they may be called, they are seldom used as tampers to pound oakum into a seam, but rather are pounded with a mallet along the seam; with the point end forward, in order to clear the old caulking out of a seam before recaulking it.  The fifth caulking iron is known as a “double crease straight iron.”  It is the iron with the broad symmetrical foot.  This is a principal caulking iron—one that is used a lot.  “Double crease” means that the blunt edge of the iron is double the thickness of a “single crease” iron, and it usually is cupped in cross section.  This iron would be used on wider seams, or at the wide top of the seam at the surface.

Another tool in this group, called a reefing hook or raker, also is used to clean out a seam, removing the loosened old caulking, freed up by the reefing iron.  This particular raker is really a different tool, called a “race” knife.  A race knife is a special knife that cuts a groove or “race” in a plank—either to delineate the waterline on a hull, or more usually to cut identifying marks in planks or barrel staves, so their relationship to their neighbors can be told when the hull or a barrel is assembled..  At any rate, a race knife makes a nice raker for a caulker.  Its presence here tells us that the owner of this kit of tools was not only fastidious about their condition, but he was also frugal, using a tool cast off from a former purpose, and converting it to his particular use.

The final tool of interest in this kit is a standard caulking mallet (and a spare handle for that mallet).  Caulking mallets are quite specialized hammers.  The head is made of wood, and usually is from 10 to 16 inches long, strengthened by iron bands that gird the head on either side of the eye for the handle, and again, near the ends or “faces” of the head.  The wood used for caulking mallets has to be extremely hard and durable.  The fanciest ones may be made of rosewood or ebony, but the usual working caulking mallets use live oak, or especially, mesquite, as the wood of choice.  A particular feature, especially of many American caulking mallets, is a slot with blind ends, cut vertically through the head, between the iron bands on each side of the handle.  These slots, usually about 1/8 inch wide, can be 3 or 4 inches long, and sometimes are “stopped” at each end, with slightly larger holes bored by a drill or brace.  All of these features can be seen in the mallet belonging to the caulking kit.

The array of caulking irons in this kit, with the majority being jerry irons, suggests that this caulker probably worked in a team of from 5 to 30 men, and his particular specialty was clearing the old caulking from a seam, and cleaning it out (with the seam rakers), so that the caulkers working behind him could concentrate on pounding new oakum into the cleaned seams.  Those workers would have used a greater variety of caulking irons, including single and double crease straight irons, “bent” irons for working on seams at some reach away, narrow “spike” and “trunnel” irons for caulking around the spike and trunnels that fastened the planks to the ship’s frame.  Also, instead of using a cast-off race knife to serve as a seam raker, specialized irons called “reefing hooks” were used for this purpose.

Pictures of tool boxes and the workers that use them do have stories to tell!

3 responses to “Ship Caulkers and Their Tools, by Sanford Moss

  1. Hi, thanks for sharing,
    Great post…
    great article ..
    like you site..continue doing it..

    Thanks for the tips

    This is really helpful.

  2. Your very welcome, Sandy did a great job on this.

  3. Great Stuff!! Sandy Moss is a wonderful man and was a fine teacher and researcher. He certainly taught me a thing or two about fish over the years… and how science is really done. I still think about him and am glad he’s continuing to share his time and experience with the rest of us!

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