Shipbuilding Terms and Phrases 

The following pages are a glossary of shipbuilding terms from United States Shipping Board Emergency Fleet Corporation publication The Building of a Wooden Ship by Charles G. Davis (1918), a long out-of-print book. These definitions will be very handy when reading the works of such authors as Davis, Howard I. Chapelle, V.R. Grimwood, and others I will reference in this blog. In some cases, I have added further clarification to a definition in the form of editor’s notes. These are in italic, contained in parentheses, and attribute the modern author of the clarification.

I 

IN-AND-OUT BOLTS: a term applied to those bolts fitted in knee, pointers and riders which are driven through the vessel’s sides or athwartship. 

INBOARD: the inside of the vessel towards the center line. 

INJECTION: a term applied to the opening in the side of a vessel combined with the pipe and valves leading from the ship’s sides to the circulating pump, thence into the condenser. Through this opening, valve, pipe and pump, the sea water for the condenser is brought. 

INNER JIB: the headsail which is directly forward of the forestay sail. 

INNER POST: the oak timber fayed on the foreside of the stern-post for the purpose of seating the transom. 

INSIDE PLANKING: the planking on the inside face of the frame, commonly called ceiling. 

IRISH PENNANT: the loose end of a rope which hangs over an awning, sail, yard or lies around the deck in a slovenly manner. 

J

JACK: a flag showing the canton or union of the national ensign with the fly. In the American flag it would be the blue field without the thirteen red and white stripes. The jack is generally flown from the jack-staff at the bow. 

JACK BEAMS: the short deck or head-timbers that do not cross the vessel, as the deck- beams or head-beams at the hatch openings. 

JACK-ROPE (JACK-STAY): the foot of some fore-and-aft sails is secured to the boom or spar by a line known as a jack-rope, running fore-and-aft through eyes which are screwed in the top of a spar, and through small thimbles which are sewed into the bolt-rope along the foot of the sail. These thimbles are generally located where the seam joins the bolt-rope. 

JACK-STAFF: the flagpole at the bow of the vessel. 

JACOB’S-LADDER: a ladder with rope sides and wooden steps or rungs for climbing the sides of vessels with high bulwarks; a temporary ladder used from the side when it is not practical to lower the accommodation ladder. 

JAW-ROPE: a piece of rope or wire passing around the forward side of a mast, the ends attached on the two horns or the jaws of a gaff, boom or spar; hardwood beads are generally strung on this rope or wire and act as rollers to prevent the rope from jamming on the mast when hoisting or lowering the sail. 

JAWS: the pieces of natural crooked wood or metal attached to the inner end of a gaff or boom on each side. These jaws fit around the mast and hold the boom or gaff into position; sometimes called “horns.” 

JEWS-HARP: a peculiar shaped shackle in the end of a chain or cable, used as a sling, to allow for quick adjustment of length, without knotting the chain. 

JIB: a triangular sail carried on the forestay, which is ahead of the foremast. 

JIB-STAY (JIB-HEAD): a fore-and-aft stay on the foremost. In most steamers this runs from near the after side of the stem-post to the lower foremast head or where only lower mast is carried, to the point on the mast where the main shrouds are attached. 

JIG: an extra purchase made fast to the end of the throat or peak halyards; the bight of the halyards is rove through the blocks, and the two ends are brought down to the deck, generally one end on each side of the mast. One of these ends is the regular hauling part and the other is a small purchase tackle, enabling the halyards to be easily set up taut; this purchase is called a “jig.” 

JIGGER: a handy billy or tackle that is used about the deck; a rig similar to a jig on the throat and peak halyards; also a sail set on the jigger-mast. 

JIGGER-MAST: aftermost mast on a four-masted vessel; also the small mast carried on the stern of yawl-rigged boats. 

JOGGLE: the process of notching a timber to fit over an obstruction or another timber; also used in a general sense when anything is notched to fit over another thing. 

JOINER: see Ship Joiner. 

JUMPER STAYS: the additional stays which lead from the lower mastheads to the top sides of a vessel, used in heavy weather: or when additional bracing is needed for the masts, as when handling heavy cargo, these stays are set up. 

K

KEEL: the fore-and-aft construction of heavy timbers scarfed end to end and extending through from the stem-post to the stern; and rudder-post, on the outside of the bottom of a vessel along the center line; the backbone of the ship on which the stem, stern-post, rudder-post, deadwood and frames are erected. The laying of the keel is the first operation in the construction of a vessel.

KEEL-BLOCKS: heavy blocks built up from the ground ways on which the vessel’s hull rests during construction. 

KEELSON (KELSON): an auxiliary keel or stringer, built over the frames on the inside of the hull extending along, over and parallel to the keel; also known as inside, center, or vertical keel. 

KERF: the cut or channel made by a saw; to form a channel in; to groove. Thus running a saw between two pieces of a scarf so as to make them fit tightly together, is known as kerfing the scarf. 

KNEE: an angular piece of timber, usually a natural crook, used to strengthen corners; sometimes made of iron or steel; a term used to indicate that a connection has been strengthened or connected with knees. 

KNEE OF THE HEAD: a large flat timber fayed edgewise on the upper forward part of the stem. It is generally formed of several pieces of hardwood coaked or tabled together edgewise. Its forepart should then form a handsome serpentine line. The principal parts are called the main piece and lacing. Its construction is not to be seen on the modem straight stem vessels, but is common where vessels carry a bowsprit, and do not have a figurehead. 

KNIGHT-HEADS (BOLLARD-TIMBERS): frame-timbers aft of and next to the stem on the outside, and continued up above the forecastle deck high enough to form the bulwarks or support for the buffalo, and support and guide the bowsprit, if one is carried; two or more stout upright timbers fastened to each side of the stem. In vessels not having a bowsprit or buffalo, the knight-heads are cut off directly below the forecastle deck. 

KNOT: a division in the log marked with cloth knots or small parceling of string worked in around the strands of a rope. When a log line is used with a twenty-eight second sand-glass the knots in the log line are spaced 47.33 feet apart: when used with a thirty second sand-glass the knots on the leg are spaced 50.75 feet apart. These measurements, also known as knots, refer to the distance that a vessel would travel in one hour’s time. The measurement or series of knots which pass overboard when a log line is used, in a given number of seconds, as described above, represents the distance in nautical miles of 6000 feet, that a vessel would travel in one hour. 

KNUCKLE: an angle in some of the timbers of a vessel. This kind of framing is often seen around the stern. Many timbers in the Hough type of vessel construction are framed with knuckles, which are particularly noticeable fore-and-aft the line made by the timber frames, forming an abrupt angle in the shape of the ship’s bottom. In shipbuilding an angle in the timber, frames or planking. 

KNUCKLE-RUN TIMBERS: timbers composing the knuckles of a vessel.