ship model blocks

This article is intended for the model ship builder and takes into account what you will be given to work on a model ship kit. It is not a dissertation on all the blocks found on ships.

Simply put, a block in boating is a single or multiple pulley used as a lever to maneuver loads of gear typically attached to fixed and running applications on a ship. In use, a block is connected to a fixed surface. A rope or line is woven through the pulleys of that block, and perhaps through one or more of the same blocks at some other end to form a rig.

This discussion will focus on the blocks used to build ship models. Due to the size of a ship model, the blocks that are used are generally block representations, a pretty poor representation at best! However, it is quite difficult to make precise, museum-quality blocks. Also, the types of blocks represented in the kits are usually limited to common blocks, sister or fiddle blocks, heart blocks, and ram’s head. Other types of locks, deadeyes, hearts, and bullseye will be played.

What follows is an overview of building blocks used in ships.

The shell is the outer covering of a block and is made of ash, elm, or iron. In model ship kits, the shell is usually walnut or boxwood. The shell could be in one piece or assembled from various components – which was always made of wood until the mid-19th century. After this time the shell was occasionally made of metal. A block consists of a casing that is made in one piece or assembled from several components, which was always made of two until the mid-19th century. After this time, the casing was made in one piece.

The shell contained a pulley, or pulley, over which the rope ran and which rotated on a pin. The sheave is the wheel on which the rope moves, and it is made of metal, guayacán (wood that has the extraordinary combination of resistance, hardness and density) or iron. The Bouch is made of metal or leather and is the center piece of the pulley that rides on the pin. The pin is made of iron or lignum-vitae, and has a head at one end: it passes through the center of the shell and the bouch of the pulley. In model ship kits, the pulley and pin are usually made of brass.

The crown and tail of a block are the ends of the shell; the latter is easily known, as it has a much deeper notch than the former to receive the splice of the strap, and in most cases the foot part, of the purchase. The Swallow is the open part between the sheave and the shell.

The Score is the slot found on the outside of the casing to receive the straps, whether single or double, depending on the use given to the cues. Scored doubles are always double dashed.

The size of a block is denoted by the length, and its classification by the flatness or thickness of the shell, the number of pulleys, the number of notches, and the quality of chiseling. A block, if it is a pulley, is called a single block; two pulleys, a double block; three sheaves, one triple, and so on, depending on the number of sheaves. If there is a punctuation, it is called a single punctuation block; if there are two scores, a double-score block, etc.

A block is supposed to carry a chord one third of its length in circumference: that is, a chord of 3 mm. block would take a 1mm. rope, a 6mm block would take a 2mm one. rope, etc. The blocks are designed to be used with a certain size of rope. Therefore, they should never be used with larger strings. Cable bent over a small pulley will distort, and any large applied tension will damage it and may even cause the cable to wear on the frame.

It is impossible to determine the size of the block to be used with the wire rope due to the factors involved. However, experience has shown that the diameter of a pulley must be at least 20 times the diameter of the rope. An exception to this is flexible wire for which smaller pulleys can be used due to their greater flexibility. Wire rope construction has a lot to do with determining the minimum diameter of sheaves to be used. The stiffer the wire rope, the larger the pulley diameter required.

Block types

common blocks

They are used for almost all common purposes, threading purchases, boat rigging, gun rigging, etc., quarter blocks, span blocks for mainsail halyards and peak brailles, jewel blocks on the mainsail. topsail and bunion yard arms for horse sail halyards, and indeed, for most of the running gear.

sister blocks

Sister blocks are tapered, the top of the block being smaller than the bottom and deeply grooved, as they are caught between the forwardmost pair of shrouds on the uppermast rig; therefore they are built not to interfere with the spread of the rig; they are also two-in-one at one end, the reef rig is passed over the top and the topsail is raised on the bottom pulley. Sometimes they fit into separate pendants.

ram head blocks

Ram’s head blocks were used to raise and take down the lower yard for furling and setting the sails. The practice of moving the lower court ended around 1660. The ram’s head block allowed a few feet of clearance when the court was raised or lowered.

Boo block at the top header

A mock block is a double block, with a double groove, tied with two simple straps, the four parts, that is, the two parts of each strap, join at the top of the block, leaving two long sinuses or eyes, which they are passed through the stern hole in the forward part of the top and tied to the stern part of the top of the mast.

Every block on board a ship has a purpose. There are at least 10 other blocks that are not described in this article. However, in most ship model kits, you will only find three or four types of blocks that represent all the blocks.

A few words about specialty blocks. We will talk about dead eyes, hearts and bull’s eyes in another article.

Dead eyes

The dead eyes are round and made of elm; They have three holes at equal distances to take the ropes of the rigging, and with a deep notch, according to their size, to round them to take the shroud. The size of a dead eye is denoted by the diameter. Dead eyes, intended for wire rigs, have a lower score. Deadeyes are particularly used to attach rat lines to the hull.

hearts

Hearts are another description of dead eyes, used to attach braces, turned at the end of the braces and fastened on the necks of the forward bowsprit braces. The lower ones, for the main or mizzen braces, are finished off with iron. Like dead eyes, they are made of elm, somewhat resembling a heart in shape, with a large hole in the center; in the largest heart there are four scores, and in the smallest three scores, to place the rope. Around the outside is a rounded groove to take the stay.

Diana

A dartboard is a wooden thimble, with a hole in the middle, rounded at the edges, with a groove around the outside for a strap or grip to attach. They are usually attached to the lower shrouds on merchant ships, to act as a fair leader for the running rig.

For the model ship builder, safety pins can be made into the most basic brass, bronze, or scrap hardwood lathes…or better yet, contact Cast Your Anchor at http://castyouranchorhobby.com or contact us at Cast Your Anchor 416-686-8529 for all your ship modeling needs.