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.

In a nutshell, a block in navigation is a single or multiple pulley used as a lever to maneuver rigging loads usually 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 tackle.

This discussion will focus on the blocks used to build model ships. Due to the size of a ship model, the blocks used are generally representations of blocks, 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, sibling or fiddle blocks, heart blocks, and ram’s heads. Other types of blocks, 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 several 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 shell that is made in one piece or assembled from several components, which was always made in two until the middle of the 19th century. After this time, the casing was made in one piece.

The shell contained a pulley, or pulley, on which the rope ran and which rotated on a pin. The pulley 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 brass.

The crown and tail of a block are the ends of the shell; the latter is easily known, since 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 cart. The Golondrina 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 always have a double line.

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 the chiseling. A block, if it is a pulley, is called a single block; two pulleys, one double block; three sheaves, a triple, and so on, according to the number of sheaves. If there is a score, it is called a single score block; if there are two scores, a block with double scores, etc.

A block is assumed to carry a chord of one-third its length in circumference: that is, a chord of 3 mm. block would take a 1 mm. string, a 6mm block would take a 2mm. rope, etc. The blocks are designed to be used with a certain size of rope. Therefore, they should never be used with larger size ropes. Cable bent over a small pulley will be distorted, and any high tension applied 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 much to do with determining the minimum diameter of pulleys 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, ship rigging, gun rigging, etc., quarter pulleys, span pulleys for spreader sail halyards and peak brails, jewel pulleys on sail topsail and topgallant yard arms for the spreader halyards, and indeed for most of the undercarriage.

sibling blocks

The sister blocks are tapered, the top of the block being smaller than the bottom and having a deep groove, as they are caught between the forwardmost pair of shrouds on the upper mast rigging; therefore, they are constructed not to interfere with the extension of the rigging; they are also two in one at one end, the reef rigging is passed through the top and the topsail is raised by the bottom pulley. Sometimes they fit into separate pendants.

ram’s head blocks

Ram’s head blocks were used to raise and lower the lower yard for furling and unfurling 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 mocking 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, are joined at the top of the block, leaving two long sinuses or eyes, which they are passed through the aft hole in the forward part of the crow’s nest and are moored at the aft 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 covered in this article. However, in most ship model kits, you will only find three or four types of blocks that represent all of the blocks.

A few words about specialty blocks. We’ll talk about dead eyes, hearts and portholes 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 from the rigging, and with a deep notch, according to their size, round them to take the shroud. The size of a dead eye is denoted by the diameter. Dead eyes, intended for wire rigging, have a lower score. Deadeyes are particularly used to attach rat lines to the hull.

hearts

Hearts are another description of dead eyes, which are used to attach the stays, are turned at the end of the stays and are clamped onto the necks of the forward bowsprit stays. The lower ones, for the main or mizzen braces, are topped with iron. Like dead eyes, they are made of elm, something that looks like 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 there is a rounded slot to take the stay.

Diana

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

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