Items of rigging equipment include devices and devices for fastening rigging, attaching it to the hull or to the spar, tightening it and working with it. The items of rigging equipment on a ship are chains, blocks, hooks, staples, butts, eyes, thimbles, and turnbuckles.
To attach the main ends of the rigging gear to the hull or to parts of the spar, eyes and butts are installed (Fig. 5.4).
A butt is a ring or half-ring 1 welded to any part of the hull or spar for attaching rigging. An eye is a metal ring that is inserted into the butt and can rotate freely in it 2.
Rice. 5.4.
1 – butt; 2 – eye; 3 – rosin block; 4 - swivel; 5 – steel cable
Koushi protect the cable from chafing when attaching it to brackets and hooks. Made from cast iron or steel. For plant cables, only round or oval steel ones are used. Each thimble must be stamped with the stamp of the manufacturer, type and number indicating the size permissible load. The thimbles are galvanized, the surfaces of their bales should not have burrs, cracks or other defects.
Gaki. Depending on the method of fastening, they are divided into ordinary and swivel. Ordinary ones consist of a toe, back and padding. If the butt and toe of the hook are located in the same plane, such a hook is called rotated, in which the plane of the butt is perpendicular to the plane of the toe, called simple. IN lifting mechanisms swivel hooks are used. Instead of a butt, they have a neck - a shank, which is sealed in a single or double swivel (Fig. 5.5).
Figure 5.5. Cargo hook
Each hook has a stamp indicating the number corresponding to the load capacity, and letter designation, for which mechanism it is intended: P - manual drive, M - mechanical.
For cargo devices, hooks with a special boss above the toe are used, which eliminates the possibility of the hook hitting the hatch coaming when lifting a load. In some cases, double-horned hooks or hooks that have a boss with an eye on the back are used in lifting mechanisms; to attach a guy to prevent rotation of the load, such hooks are called penter-hooks.
Of the special hooks, the most common are folding hooks - snores and verb-hooks. The latter are used when you need to quickly release tackle under tension. The hooks are selected according to the permissible load. When accepting the hooks onto the ship, it is necessary to check that they are free of cracks, shells and other defects. Hooks must be galvanized or painted and have the manufacturer's mark.
Can be open and closed types(Fig. 5.6). To attach gear and other parts to them, their screws end in eyes, hooks or forks. Each lanyard is numbered according to its load capacity and the screws must move freely in and out of the sleeve. The threads are lubricated with grease.
Rice. 5.6. Lanyards:
1 – open; 2 – closed; 3 - swivel
Shackles used to connect individual chains and cables, for connection to parts of the hull or spar (Fig. 5.7). The bracket consists of a back, tabs with eyes and a pin. Can be straight or curved. The pin in the brackets is held in place either by threading or by an external cotter pin.
Rice. 5.7 Bracket
Rigging shackles are available in five types: SA, SB, PV, PG and PD. Staples of type SA (straight with a threaded pin) and SB (straight with a cottered pin) are used for steel cables, staples of type PV (straight with a threaded pin), PG (straight with a cottered pin) and PD (curved with a threaded pin) - for synthetic cables The staples and their parts must not have cracks, holes, burrs, etc. The head of the pin must be free of distortions and fit snugly against the side supporting surface lugs. For threaded pins, the threads should not have broken threads or dents, and the pin itself should be screwed in without jamming. To protect against corrosion, the brackets must be galvanized or painted, and their rubbing parts must be lubricated with grease.
Block consists of a housing, one or more pulleys, and an axis called a dowel on which the pulleys rotate. Depending on the material, the cases are made of wood or metal. Frame wooden block consists of external and internal cheeks and liners made of oak or ash boards. For metal blocks, the body consists of steel jaws connected by bolts, or is made in the form of a special clip. For both metal and wooden blocks, pulleys are most often made of steel or cast iron. Around the circumference of the pulley there is a groove for the cable, called a bale. To attach to the ship's hull, spar or rigging, the block has a suspension in the form of a bracket, eye or hook.
The suspension is attached to the block body using a fitting, which is a metal strip running outside the body (external fitting) or from the inside (internal fitting).
Single-pulley blocks, in which one of the jaws (or frame) is made partially folding, i.e. rosin blocks (Fig. 5.4), are used in cases where it is necessary to insert the cable into the block not from the end, but from its middle. Caniface blocks are selected in such a way that the diameter of the block pulley is larger diameter cables at least 10 times for synthetic cables, 12 - 18 times for steel ones.
The ship must accept blocks that bear the mark of their testing and the manufacturer's trademark.
Gordeni and thali. The simplest design is a single-pulley block. A cable passed through such a block, fixed motionless, is called a gorden (Fig. 5.8). The arbor allows you to change the direction of thrust when lifting and moving a load, but does not provide any gain in strength. Single-pulley blocks with halyards passed through them are used for raising flags and pennants, signal lights and signs.
Rice. 5.8. Gorden
The following types of hoists are used on ships: grab hoists - portable hoists based between two single-pulley or single-pulley and double-pulley blocks (Fig. 5.9). Both blocks have swivel hooks and are used for deck work - for tightening gear, when installing a plaster, pulling a load, etc. To obtain biggest win In force, the hoists must be laid in such a way that the running plow comes out of the movable block.
Rice. 5.9. Tali
Guinea- multi-pulley hoists, based on a thick cable between large blocks, capable of withstanding heavy loads. They are used when arming heavy booms (cargo gins), as well as in a number of emergency cases, for example, when refloating a ship, etc. To calculate the hoists, it is necessary to divide the weight of the cargo by the number of pulleys through which it passes. But since friction forces act on the pulleys, before starting the calculations, take into account that the weight of the load increases by 5 - 10% on each pulley through which the plows pass.
In addition to cables, ships use rigging chains made of round steel, the diameter of which is the main parameter - the gauge that characterizes the dimensions of the chain. Rigging chains are divided into calibrated and uncalibrated.
A calibrated chain has all links of the same size with very slight deviations, which is why it is used in lifting mechanisms for working on special sprocket drums.
Significantly larger deviations are allowed in the dimensions of individual uncalibrated circuits. These chains can be used for securing and lifting loads, as standing and running rigging and in some other cases. Rice. 1 Hooks: a - simple, b - rotated, c - swivel, d - double swivel, d - cargo, f - snores, g - penter-hack, z - verb-hack
Lifting chains have good strength and significant durability, but they have large mass and very low elasticity. In addition, during severe frosts, chains easily break from sharp blows.
Chains must be protected from corrosion by systematic lubrication, turning Special attention to the points of contact between the links. They should be stored hanging in dry, ventilated areas. A chain folded into coils is subject to intense corrosion.
Items of rigging equipment
The main items of rigging equipment for modern ship are hooks, staples, thimbles, lanyards, blocks, hoists.
Gakami are steel hooks used on ships for various purposes (Fig. 1).
Depending on the purpose, place of application and design, the following hooks are distinguished:
- Simple ones, in which the plane of the butt is perpendicular to the plane of the toe;
- Rotated, in which the butt and toe are in the same plane;
- Swivels, having a hinged connection with the butt, which ensures rotation of the hook around the axis of the neck;
- Double swivels, in which the hook can rotate around the axis of the neck, and the butt swings on the axis of the earring;
- Weight hooks, or pendant hooks, have a toe curved inward, covered with a special protrusion, so the hook does not touch protruding parts during operation;
- Hrappers, consisting of two simple hooks, put on the butts on a common ring (eye); when folding the hooks, a closed ring is formed, which reliably secures the tackle or sling;
- Penter hooks, which have a pad in the lower part of the back for attaching a guy;
- Verb-hooks are folding hooks in which the folding toe is held by a special link, knocking down which can easily give away the tackle even when it is pulled tight.
Hooks that work primarily in bending have relatively low strength, and therefore, when working with heavy loads, they should be replaced with rigging shackles.
Bracket(Fig. 2) - a curved rod with eyes at the ends into which the pin is threaded; most often the pin is secured with a screw thread, which is available at its end and in one of the eyes. In this case, the head of the pin has a small butt, into which a pile is placed when screwing and unscrewing. In heavy-duty brackets, the pin is not threaded and is secured with a cotter pin.
The shape of the rigging brackets can be straight or round. Straight ones are used for steel and plant cables. In the latter case, with the same diameter of the rod, the bracket has a larger width. Round brackets are used only for plant cables.
Rice. 2 Rigging shackles a - straight for steel cable, b - straight for plant cable, c - round To fasten various parts using a hook or brackets, round or oblong eyes - butts - are welded to the ship's hull. Rings - eyelets - are often passed through the butts, which simplifies the installation of a hook or staple.
Hooks and staples must be systematically inspected and, if cracks, bends and significant wear are found, replaced with new ones. Swivel hooks should be periodically “walked around” and the rubbing parts should be lubricated.
(Fig. 3) - round, triangular or teardrop-shaped frames made of metal, having a groove on the outer surface and serving to seal the ends of the cable in cases where they are attached to the butts or connected to each other with staples and protect the cables from chafing.
Rice. 3 Throats: a—heart-shaped, b—round (Fig. 4) - devices for tightening various gear, as well as for securely fastening various objects and loads while traveling. The most common is a screw lanyard, which consists of a coupling that connects two screws: one with a right-hand thread and the other with a left-hand thread. When the coupling is rotated in one direction or another, the screws will simultaneously be unscrewed or screwed in, increasing or decreasing the length of the lanyard. Depending on the purpose of the lanyards, the screws may end with hooks, staples or butts.
Rice. 4 Lanyards: a - open; b - closed; c - swivel; 1 - hook; 2 - bracket; 3 - screws; 4 - coupling; 5 - butt Screw lanyards require constant maintenance. They must always be free of rust and lubricated. In all possible cases, and especially during repairs or long-term lay-up of the vessel, the turnbuckles should be covered with painted canvas covers, having previously lubricated them.
(Fig. 5)—devices used for lifting heavy objects and changing the direction of thrust. The block consists of a housing, inside of which there is one or more pulleys rotating on an axis (pin). The pulleys have a groove (keep) around their circumference that prevents the cable from coming off the pulley. Depending on the number of pulleys, there are one, two, three and multi-pulley blocks.
On ships, metal blocks are mainly used, and only when working with plant cables - wooden and plastic ones. To equip the blocks, the cable must be passed between the cheeks. However, threading the cable from the end is inconvenient and sometimes impossible if the cable is taut. Therefore, single-pulley blocks with a folding cheek are used. Such blocks are called rosin blocks. The folding jaw allows you to insert the middle of the cable into the block without threading it from the end.
Rice. 5 Blocks: a - metal, b - rosin blocks When working with blocks, it is necessary to ensure that their dimensions correspond to the cables used. Blocks with insufficient pulley diameters cause excessive bending of the cables, which leads to their premature wear. Pulley diameter metal block must be at least 10-15 diameters of the steel cable. For plant cables, the diameter of the pulley should be twice the circumference of the cable.
Blocks require constant maintenance. They must be periodically disassembled, cleaned of dirt and rust, and lubricated rubbing parts. During disassembly, the block is carefully inspected and, if cracks and significant wear of the dowel or pulley are found, replaced with a new one.
(Fig. 6) - the simplest lifting mechanisms consisting of blocks. Between the blocks there is a cable called a shovel. The end of the lever, for which traction is performed, is called the running end, and the fixed end is called the root end. One of the blocks, fixed in place, is called stationary, and the second, rising along with the load, is called movable.
Rice. 6 Hoists: a - for lifting loads, b - for tightening gear, 1 - fixed block; 2 - movable block; 3 — running end of the lapar Hoists are usually used to gain strength when lifting weights and only in certain cases to change the direction of the pull.
When lifting using hoists, the weight of the load is distributed equally across all branches of the lopar. Therefore, to lift the load to the running end of the paddle, it is enough to apply a force, in n times less than the weight of the load being lifted, i.e.
where n is the number of loaded branches of the lapar.
In this case, if the running end of the lopar leaves the fixed block, it is not counted in the total number of loaded branches and, therefore, the gain in force will be equal to the total number of pulleys in the movable and fixed blocks. In maritime practice, especially when pulling gear, rigging is also used in which the running end of the lopar comes off the movable block. In this case, the running end must be taken into account along with other branches of the lapar, so the gain will be equal to the total number of pulleys plus one.
Rice. 7 Types of hoists: a - gorden, b - grip hoist, c - gintsy, d - gini Thus, the gain in strength is various schemes the base of the hoists is equal to the number of branches of the lopar going from the movable block to the non-movable one, including the running end.
There are hoists various designs and load capacity (Fig. 7). Most simple view The hoist is a gantry - a stationary single-pulley block through which the cable is passed. The use of a gorden does not give a gain in strength, but it allows you to change the direction of thrust. Therefore, the arbor is used only for lifting small loads.
Widely used on ships are grabs, which are based between two and one-pulley blocks, and the root end of the shovel is fixed to a single-pulley block. These hoists are used for lifting small loads, cleaning ladders and performing other ship work.
Small hoists, based between blocks with the same number of pulleys and wound behind some kind of tackle to tighten it, are called gintsy. When there are more than three pulleys in each block, such hoists are called gins. Gini is used when lifting heavy loads.
The base of the hoists (Fig. 8), i.e. inserting the cable into the block system is usually done with blocks laid on the cheek; hooks or staples must be located outwards. The root end of the lopar is passed sequentially through all the pulleys, starting with the lower pulley of the block that should be the upper one.
The lapar should be passed clockwise, since with such a base the hoists will spin and get tangled less. When the shovel passes through all the pulleys, its root end is secured to a special bracket located on one of the blocks. When founding high-noise hoists (guineas), the root end is first passed through the middle pulley. In this case, the running end will also move off the middle pulley of the upper block, which prevents the blocks from skewing during traction.
Rice. 8 Foundation of hoists: a - gnits; b - tini (diagram), 1 - upper block; 2 - root end; 3 - lower block; 4 — running end; I - VII - sequence of piloting the Lapp When working with hoists, sharp jerks should be avoided, which can lead to breakage of the paddle or damage to the blocks. When lifting a load, do not allow the lower block to be pulled close to the upper one.
All rubbing parts of the blocks should be well lubricated. After completing the work, the hoists must be carefully laid out, avoiding tangling of the hoist. To properly lay the hoists, they are carried on the deck and the running end is laid with hoists or rolled into a round coil. Then the hoists are intercepted in several places with a pile heel and the hoists are laid in a coil.
The hoists should be stored in a dry, well-ventilated area, hanging. If they are stored for a long time, they must be periodically taken out to dry.
All items of rigging equipment must bear the mark of the Register or the manufacturer.
Rigging equipment used when securing containers
Reliable fastening of containers, especially those transported on deck, required the introduction of special devices and parts. Their remarkable feature is their clear standardization and typification, which makes it possible to use these devices for almost all types of containers transported by sea vessels.
In Fig. Figure 9 shows the most common parts and assemblies of container fastenings.
Rice. 9 Rigging equipment used for securing containers Conical grippers (conlocks) (Fig. 9, A) designed for connecting containers to each other or to the deck. Locking grips (twist locks) (Fig. 9, b, c) equipped with an automatic or manual locking device. Screw clamps - fittings (breeches) (Fig. 9, G) Usually rows of containers are pressed against each other or against the side of the ship. In Fig. 9, d shown are recessed fittings (steps) that include cone or locking jaws.
Support plates for containers are shown in Fig. 9, e. Shown in Fig. 9, and butts or fittings recessed into the deck are designed to attach lashings or chains that tighten rows of containers. Fastening chains equipped with hooks or quick-acting fastenings are shown in Fig. 9, h, and the cable lashings are shown in Fig. 9, And.
PENTER-GAK -PENTER-GAK
PENTER-GAK
P.-G. there are one-horned And two-horned.
Samoilov K. I., 1941
Hook in maritime affairs
Gak (mor.)
,PENTER-GAK
- so special type, tied into the sling of the lower block of fish hoists. It is laid behind the arm of the anchor when lifting the latter onto the rustic.
P.-G. there are one-horned And two-horned.
Samoilov K. I. Marine Dictionary. - M.-L.: State Naval Publishing House NKVMF USSR , 1941
Hook in maritime affairs Hook in maritime affairs is an iron hook of a special shape, used on ships for placing blocks or tackle in butts, rolls, etc. Parts of the hook: butt, toe and back. There are three types of hooks: simple, folding, swivel, cat-hook, pen-hook and crane hook. Simple G. is used almost everywhere in armament
Hook (nautical) Hook (nautical) an iron hook of a special shape, used on ships for placing blocks or tackle in butts, rolls, etc. Parts of the hook: butt, toe and back. There are three types of hooks: simple, folding, swivel, cat-hook, pen-hook and crane hook. Simple guns are used almost everywhere in a ship's armament. Skla
Penter-huck
Together or separately? Spelling dictionary-reference book. - M.: Russian language. B. Z. Bukchina, L. P. Kakalutskaya. 1998 .
See what “penter-gak” is in other dictionaries:
A special type of hook, tied into the sling of the lower block of fish hoists. It is laid behind the arm of the anchor when lifting the latter onto the rustic. Penter like that. P.G. are one-horned and two-horned. Samoilov K.I. Marine dictionary. M.L.: State Naval... ... Naval Dictionary
An iron hook of a special shape, used on ships for placing blocks or tackle in butts, rolls, etc. Parts of the hook: butt, toe and back. There are three types of hooks: simple, folding, swivel, cat hook, penter hook and crane hook. Simple G.... ... encyclopedic Dictionary F. Brockhaus and I.A. Efron
- (Fish) one of the gears used to remove the anchor on a ship. The f. consists of a fish pendant and hoists. The fish pendant is braided around the thimble of the penter hook and goes into the block on the fish beam and stretches along the deck with the tackle through the rosin block. If F. has... ... Marine Dictionary
Shtert, taken by the penter hook. This pin is used to lay the penter hook behind the anchor. The one-horned penter has one F.Sh., the two-horned one has two. Samoilov K.I. Marine dictionary. M. L.: State Naval Publishing House of the NKVMF of the USSR, 1941 ... Marine Dictionary
| The steering device must have two drives: main and auxiliary. The main steering drive is the mechanisms, actuators for shifting the rudder, power units of the steering drive, as well as auxiliary equipment and means for applying torque to the stock (for example, a tiller or sector), necessary for shifting the rudder in order to control the vessel in normal direction. - low operating conditions. Auxiliary steering gear is the equipment necessary to steer the vessel in the event of failure of the main steering gear, excluding the tiller, sector or other elements intended for the same purpose. The main steering drive must ensure that the rudder can be shifted from 35 0 on one side to 35 0 on the other side at maximum operating draft and forward speed of the vessel in no more than 28 seconds. The auxiliary steering gear must be capable of shifting the rudder from 15° on one side to 15° on the other side in no more than 60 seconds at the vessel's maximum service draft and a speed equal to half of its maximum forward service speed. The auxiliary steering drive must be controlled from the tiller compartment. The transition from the main to the auxiliary drive must be carried out in a time not exceeding 2 minutes. The steering wheel is the main part of the steering device. It is located in the stern and operates only while the ship is moving. The main element of the steering wheel is the feather, which can be flat (plate-shaped) or streamlined (profiled) in shape. Based on the position of the rudder blade relative to the axis of rotation of the stock, they are distinguished (Fig. 6.2): - ordinary rudder - the plane of the rudder blade is located behind the axis of rotation; - semi-balanced steering wheel - only a large part of the rudder blade is located behind the axis of rotation, due to which a reduced torque occurs when the steering wheel is shifted; - balancing rudder - the rudder blade is so located on both sides of the axis of rotation that no significant moments arise when shifting the rudder. |
| An active rudder is a rudder with an auxiliary screw installed on it, located on the trailing edge of the rudder blade (Fig. 6.3). An electric motor is built into the rudder blade, driving the propeller, which is placed in an attachment to protect it from damage. By turning the rudder blade together with the propeller through a certain angle, a transverse stop appears, causing the vessel to turn. Active rudder is used at low speeds up to 5 knots. When maneuvering in tight water areas, the active rudder can be used as the main propulsion device, which ensures high maneuverability of the vessel. At high speeds, the active rudder propeller is switched off and the rudder is shifted as usual. Separate rotary nozzles (Fig. 6.4). The rotating nozzle is a steel ring, the profile of which represents the wing element. Nozzle inlet area more area day off. Propeller screw is located in its narrowest section. The rotary attachment is installed on the stock and rotates up to 40° on each side, replacing the rudder. Separate rotary nozzles are installed on many transport vessels, mainly river and mixed navigation, and provide their high maneuverability characteristics. |
| Before each departure to sea, the steering device is prepared for operation: all parts are carefully inspected, any detected faults are eliminated, the rubbing parts are cleaned of old grease and lubricated again. Then, under the guidance of the officer in charge of the watch, the serviceability of the steering device in operation is checked by testing the rudder. Before shifting, you need to make sure that the stern is clean and that no floating devices or foreign objects interfere with the rotation of the rudder. At the same time, check the ease of rotation of the steering wheel and the absence of even minor jams. In all positions of the rudder blade, the correspondence of the indications of the steering indicators and the time spent on shifting are compared. The tiller compartment must always be locked. The keys to it are stored in the chart room and in the engine room in specially designated permanent places, the emergency key is at the entrance to the tiller compartment in a locked cabinet with a glazed door. Two independently operating lines must be installed between the navigation bridge and the tiller compartment Upon arrival at the port and upon completion of mooring, the steering wheel is placed in a straight position, the power to the steering motor is turned off, the steering gear is inspected, and if everything is found in proper order, the tiller compartment is closed. |
Gaki, their structure, types. Determination of the lifting capacity of the hook. How is the hook put on the butt? For what defects is it unacceptable to use a hook?
Rigging hooks- forged steel hooks used for fastening cables, chains, laying blocks, slings, etc. Consists of a butt with an eye, a back, a toe...
There are three types of hooks: simple, folding, swivel, cat-hook, pen-hook and crane hook.
- Simple - used almost everywhere in ship armament.
- Foldable- on boats and in general in those cases when it is necessary to prevent the hook from catching on something with the toe.
- Swivel- can turn around in its bar and is very convenient where the tackle or tackle has to be untwisted without removing the hook from the butt in which it is embedded.
- Kat-gak-hook of the lower cut-block; With this hook the cat is placed in the anchor bracket.
- Penter-huck- like at the end of the fish, with which the anchor rises behind the uterus.
- Crane - of special strength, has the shape of an anchor and is made at the end of crane guineas (thick hoists); used for lifting weights, e.g. masts, steam boilers, etc.
Fig.1 Rigging hooks.
Ordinary hooks are simple in shape (Fig. 1,a ) , if the plane of butt 2 is perpendicular to the plane of the back and rotated (Fig. 1, b), if the butt, back and toe lie in the same plane. By means of the butt, the hook is embedded in the cable fire or secured in the suspension of the structure. A variety of ordinary hooks is the penter-hook (Fig. 1, c). In the lower part of the back it has a pad for attaching a guy. For cargo pendants, rotated hooks of a special design are used. This hook, called a cargo hook, or pendant hook ( Fig. 1, d), has a toe curved inwards, covered with a special tide on top. This design of the hook prevents it from getting caught on the protruding parts of the ship's hull and the cargo hatch when lifting the cargo.
Swivel hook (Fig. 1, d) Instead of a butt, it has a neck, which ensures the hook is secured and freely rotates in the block frame or other suspension. Swivel hooks are used to prevent cables from twisting.
Verb-hack (Fig. 1, f) consists of the hook itself with an elongated folding toe and butt (2) in the form of an eye, a round fastening link (3), an elongated link (4) and locking (5) and connecting (6) links connected to it. The latter is embedded in a butt welded to the deck or superstructure. The dimensions of the locking link allow it to be put on the toe of the hook pressed against the extended link after the cable end or a link of the rigging chain is laid on the hook. When the gear attached to the hook is in a tense state, spontaneous release is excluded, but if you knock the locking link off the toe of the hook, the gear is quickly released.
Snores (Fig. 1,g) They are a folding hook formed by two simple hooks. When folding the hooks, a kind of closed ring is formed, which, being ensconced, ensures reliable fastening of the sling or cable end.
Hooks experience stress mainly through bending. Their strength is significantly less than the strength of rigging brackets.
The hook is stamped with a number corresponding to its capacity. Working strength P = 0.6d 2 (kg), d is the diameter of the backrest in mm. The hooks are placed behind the butts, frames, and slings so that the toes point up (the tension is taken by the back)
Butt(Fig.2)- a steel bolt with a ring or a special forging with an eye instead of a head in the upper part. Butts are used to attach standing rigging gear to the ship's hull, blocks lifting devices and portable anchor chain stoppers to the deck, as well as for other purposes.
Rice. 2. Laying hooks behind the butts and eyes:
The hooks are systematically inspected to detect cracks, cavities and other defects and the rubbing surfaces are lubricated. The swivel hooks move around periodically. It is unacceptable to use the hook if there are cracks, bent or worn out butts and backs. Worn necks or heads of swivel hooks (>10% of thickness)