FAQs

Frequent Questions,
Helpful Answers

Have a question concerning your Thern product? Chances are it has been asked before. Below are helpful answers to many of our most frequently asked questions. If the answer you are looking for is not provided below, please contact us!

Bulk Material Handling

If the conveyor tensioning system employs a counterweight design, a slow-speed winch is the best choice. Thern’s 4HBP and 4BP electric winches feature a simple single-speed control and are an ideal fit for this sort of system. Thern can custom size or custom configure the winch to match the required load and travel distance.

If the conveyor tensioning system requires constant tension from the winch, Thern’s 4HBP and 4BP electric winches can be customized with high HP motors and fast rope speeds/reactions to maintain steady conveyor tension/operation. Constant tension applications typically require motor encoders, blower coolers, and sophisticated VFD controls.  

Thern’s 4BP electric winches are commonly sized up to 50,000 lbs. Our 4HBP Series can be custom configured for capacities nearing 100,000 lbs.! Leave the heavy lifting to Thern!

Thern barge mover systems employ heavy-duty, industrial-rated 4HBP and 4BP electric winches with fully enclosed/lubricated gearing. These winches are customizable according to system and site conditions. Typical systems include controls with automatic tensioning systems, manual rigging modes, and straightforward joystick controls.

Typically, two electric winches are utilized with opposing pull directions to move and precisely position barges. Thern’s barge system control interface provides simultaneous operation of both winches, while automatically maintaining appropriate rope tensions. 

Thern’s barge mover electrical control systems are located where the customer prefers. Wireless radio controls are also available as a popular option in addition to the operator console.

The Thern 4HS Series electric winch is an industry-standard railcar puller when a drum clutch feature is desired for free spooling release of wire rope. Please note that winches with clutches are generally employed only for systems intending one-directional moving of railcars.

Two-way movements of railcars are typically accomplished by means of a “closed-loop” rigging system, controlled by a single electric winch. Wherever this is desired, Thern recommends closed loop-type railcar mover systems for several reasons:  

  • These systems provide a high degree of safety, as the railcar movement is always constrained by the winch. This is of particular importance if any grade exists.
  • The pull rope does not need to be manually pulled to reach railcar hook points. The winch is operated to run the rope and hook to the desired location, eliminating rerigging cables and improving operational efficiency.  
  • Reversing the load may not be anticipated during use, but when an overshoot occurs, the closed-loop winch system can easily reverse the railcars. 

Thern’s 4HBP Series electric winches are designed for heavy pulling applications and feature fully enclosed/lubricated gearing. Thern designs and manufactures custom-sized 4HPF/4HBP winches to match load and travel requirements for any installation.

The travel distance provided by a closed-loop system is determined by the size of the railcar puller winch drum. Thern commonly builds drums providing over 500 ft of active load travel. If the travel requirement becomes excessive, it may be necessary to unhook/rehook the cars more than once to complete the full travel span. All cars can remain connected through the multi-step movement process. 

Thern’s 5PT10 and 5PT20 Commander® Series davit cranes have a 4WP2T model electric winch option available for these long lifts. This unit has a larger drum to accommodate more cable for lifts of 150 feet and longer. Crane load ratings over extended lift distances may change slightly depending on the extent of the lift distance, so we encourage you to contact our technical sales team to discuss the specific details of your application so that we can recommend the best davit crane and electric winch combination for your long-lift needs.

Absolutely. Thern can offer motors and electric control systems suitable for all 3-phase power sources. In fact, 3-phase power offers superior performance and speed over single-phase power. We work with globally recognized suppliers who will provide us with a suitable motor to match your available on-site power source, whether 50 HZ or 60 HZ.

Thern offers stainless steel hand winches and also offers cranes in either type 304 or 316. Should you need a motorized electric winch or larger davit crane, Thern offers an epoxy finish that provides excellent protection against the most corrosive environments.

Thern’s industrial-duty 4HPF/4HBP/4BP Series electric winches can be easily customized for multiple drum compartments and wire ropes. The available grooved-drum feature provides uniform pay-in/payout.

We can offer electric winches with totally enclosed gearing in an oil bath. This greatly reduces the amount of maintenance to the gearbox and protects the gearing from nearby dust and debris. Units with enclosed gearing are available across the entire range of capacities that Thern offers.

Yes, many of our 4HPF/4HBP electric winches are designed specifically for load-out chute applications which require dual drum compartments and dual ropes. These winches typically feature grooved drums combined with drum-mounted rotary limit switches, providing highly repeatable load travel distance and constraints.

Thern’s heavy-duty 4HPF/4HBP/4BP Series electric winches are available with a wide range of load ratings and speeds. Many models are easily customized to accommodate non-standard drum widths to best suit short fleet distances or other installation factors. Multiple drum compartments are available for stackers requiring multiple wire ropes.

Yes, many of our 4HPF/4HBP Series electric winches are designed specifically for radial stacker applications which require dual drum compartments and dual ropes. Our winches typically feature grooved drums combined with drum-mounted rotary limit switches, providing highly repeatable load travel distances and constraints.

You didn’t say whether your environment was extremely hot or extremely cold, but either way, the answer is yes! Thern can equip the electric winch gearbox with the appropriate lubrication for your environment to provide trouble-free operations from -40°F to +130°F (-40°C to +54°C). We can also provide air-conditioned motors and control panels, as well as heated ones. No matter your environment, our technical sales team can find you the perfect match.

Energy

Thern manufactures winches, hoists, and davit cranes. Our standard and customized products are used for wind turbine maintenance. We can customize our products for installation on or inside the nacelle if needed.

Technicians can install Thern winches inside a wind turbine’s nacelle or its tower to lift equipment from ground level to the power generator.

Thern manufactures standard and custom lifting and pulling equipment suitable for high environmental impact environments, such as hydroelectric power generating systems. Our heavy-duty winches include sealed gear reducers and a corrosion-resistant epoxy finish with zinc-rich primer.

Government / Defense

Thern is a winch and crane manufacturer that specializes in lifting and pulling equipment. We have decades of experience designing and manufacturing products that comply with various detailed requirements specific to all branches of the military and those developed by global engineering firms.

Thern has many winches and davit cranes that qualify for government or defense purchase and use. They already have assigned cage codes.

Thern employs sales and engineering professionals with years of experience working with military and government specifications. Our in-house engineering team regularly designs custom winches and davit cranes that comply with complex specification requirements.

Manufacturing

Thern offers several permanently-mounted davit crane options, such as the 5FT20, 5FT25, or 5FT40. Available in hand- or electric-configurations, these heavy-duty models provide substantial lifting capacity.

Absolutely. All portable davit cranes have versatility in reach, capacity, height, crane size, and more. The user can leave the crane in the base permanently if desired.

The Thern 4WS or 4HS are both excellent options. Both electric winches are heavy-duty, economical, and have an extensive capacity range.

The Thern 4HPF, 4HWF, or 4BP Series. These heavy-duty electric winches have a large capacity range and feature gearing protected by an enclosed oil bath for minimal maintenance and durability in outdoor, dusty environments.

Thern offers the 4WP2, 477, or 3WG4 Series. These portable electric winches operate on 115 volts and are lightweight/versatile.

The Thern 4WP2D8 Series. This portable electric winch comes with many voltage options and is light and versatile. It features line speeds ranging from 26 to 40 fpm.

Yes! And yes! Thern offers spur gear hand winches and worm gear hand winches without brakes for horizontal pulling applications only. However, we offer winches from 1,000 lb. to 10,000 lb. capacities with brakes for vertical lifting and positioning. The brakes are automatic, so when the user removes their hand from the handle, the brake will hold the load in place without further steps. Forget about the frustration of setting the brake on your boat trailer winch. Thern hand winch brakes are automatic, reliable, and fail-safe!

Mining

If the conveyor tensioning system employs a counterweight design, a slow-speed electric winch is recommended for maintenance operations. Thern’s large 4HBP and 4BP winch families are an ideal fit combined with a simple single-speed control. Thern can customize the size of the winch to match the required load and travel distance, as well as the available fleet distance.   

If the conveyor tensioning system requires a “constant tension” type winch, Thern’s 4HBP electric winches can be provided with high HP motors and fast rope speeds/reactions to maintain steady conveyor tension/operation. Constant tension applications typically require motor encoders, motor coolers, and sophisticated custom VFD controls. Available grooved drums provide repeatable travel distance and accurate position monitoring.

Yes, many of our 4HPF/HBP winches are designed with dual drum compartments for dual ropes. Such electric winches typically also feature grooved drums to provide highly repeatable and synchronized rope/load travel distances. Drum-mounted rotary limit switches ensure accurate positioning every time.

Draglines generally fall into two categories. Most are based on standard lifting cranes that have been modified for the task of pulling or scraping large amounts of material. These “crawler type” cranes have an electric winch added to the front of the equipment that functions as the dragline. The other type of dragline is so massive and purpose-built that they have to be constructed on-site and will never leave the location where they are constructed. Smaller draglines are typically used to support civil engineering projects, such as road construction and canal dredging, while larger draglines will be dedicated to mining operations.

Thern’s industrial-duty 4HPF/4HBP Series electric winches are available with a wide range of load ratings and speeds. They are also easily customized for varied drum capacities to match required process factors. Hydraulic-powered versions are also available.

Industrial-duty Thern winches are an ideal match for repeating open/close furnace door processes. Our electric winches can be custom designed with multiple drum compartments for proper rope alignment to the furnace door size and lifting points. Grooved drum features provide uniform and repeatable pay-in/payout rope travel distances. Winches are available for a wide range of load ratings and speeds.

Yes! Please contact us for a discussion of your application, and we can work to create a custom electric control system. Features can include position limiting, torque limiting, VFD, speed ramp up/down, position monitoring, slack line detection, and many other possible features.

Thern’s industrial-duty 4HPF/4HBP Series electric winches are available with a wide range of load ratings and speeds. They are also easily customized for varied drum capacities and/or to match other required process factors. When desirable, an optional clutch feature will allow the free spool of rope.

Thern’s 4WP2 or 3WG4 winch options are available for positioning smaller carts requiring lower line pulls. Gearing is enclosed in a permanent oil bath so that it remains protected from railyard or mining dust/debris. Call Thern to discuss your cart’s size and application requirements to determine which electric winch option is sized best for your exact needs.

Two-way movements of rail carts are typically accomplished by means of a “closed-loop” rigging system, controlled by a single electric winch. Thern recommends closed-loop type systems for several reasons: 1) These systems provide a high degree of safety, as the load movement is always constrained by the electric winch. This is of particular importance if any grade exists. 2) The pull rope does not need to be manually pulled out to reach hook points.  The electric winch is operated to run the rope and/or hook to the desired location, improving efficiency and ergonomics. 3) The need for reversing the load may not be initially anticipated, but when an over-shoot occurs, the closed-loop winch system can easily reverse the cart for optimum positioning!

Floating dredges vary greatly in size and purpose. The largest systems are typically utilized for underwater mining, while small and mid-size floating dredges can be used for a variety of purposes from environmental restoration of beaches and marshes to removal of contaminated soils and maintenance of water treatment ponds. Electric winches provide multi-axis positioning of the dredge within the project, holding the dredge in position during operations, then allowing remote or manned repositioning of the dredge to continue work within the site.

Thern’s industrial-duty 4HPF/4HBP Series electric winches are available with a wide range of load ratings and speeds. They are also easily customized for varied drum capacities to match required process factors. These winches pair well with single- or variable-speed electrical control systems to provide optimal control of the floating dredge system.

Yes! Please contact us for a discussion of your application, and we can work to offer an electrical control system to position your floating dredge in accordance with your project needs.

Oil Rigs

Thern offers multiple sizes and styles of pneumatic winches designed specifically for handling drill pipe and lifting other equipment from the deck of a drilling rig. Our TA Big Red Series and MTA Series of more compact mini tuggers range in size from 2.5-ton to 10-ton lifting capacity. These are available with local or remote operator control to fit unique layouts of rig platforms. Brake systems include choices of a manual or automatic band style or automatic disc type. Roller pressure bars, rotary travel limit switches, and a manual drum lock are also available if needed.

Thern offers a variety of pneumatic winch and electric winch models for flare stack and tip applications. Thern’s pneumatic MTA and TA winches range from 1-ton to more than 10-ton capacity, with available line speeds of 10 FPM to over 100 FPM. Thern’s 4HPF and 4HBP electric winches are available with similar ratings and can be fitted with hazardous environment-rated motors and controls! All the above models feature totally enclosed, oil-bath gear reducers.

Thern’s 477 Series is a compact, versatile winch that serves well in racking/monkey board applications, as they are tailor-made for quickly pulling and positioning pipe segments to keep your drilling operation running efficiently.

Yes, yes, and yes! The 477 Series electric winch can be outfitted with a suitable motor for your available local power source.

Thern can offer hazard-class electrical motors for the 477 Series and all our other electric winches when needed. Please know the classification that applies to your environment, and Thern will be happy to quote an electric winch and control package that meets your requirements.

Thern’s MTA Mini Air Tugger Series is a perfect option to consider. With a maximum capacity of 2,700 lbs. and line speeds of approximately 40 feet/minute and greater, this compact air winch will fit in tight spaces on a rig deck and can be used for lifting or pulling smaller loads.

Thern’s MTA1000 air winches operate on a minimum of 90 PSI and 60 CFM, while the MTA2000 air winches’ performance is based on a minimum of 90 PSI and 140 CFM.

Thern’s worm gear hand winches have gearing that is totally enclosed in an oil bath, which is perfect for use throughout an oil rig. Enclosed gearing results in far less maintenance compared to spur gear units and better protection of the gears against harsh elements. We offer worm gear hand winches with capacities of up to 4,600 lbs. to serve a number of oil rig applications.

Yes, Thern can offer 4WP, 477, and 3WG4 models with pneumatic motors to mount on davit cranes. We will want to know more about the available pressure and flow in these locations, but we will be happy to offer a pneumatic winch sized for the davit crane of choice for your application.

Absolutely. Thern offers rotational bearings with our portable davit cranes that serve two primary purposes: 1) They aid in crane rotation during use to make workers’ duties easier and safer. 2) The bearings have a series of positional locks every 30 degrees, so the crane can be locked in position at any time—whether in use or not. Given the extreme conditions on an oil rig, this is a great accessory to pair with Thern portable davit cranes for added safety.

Thern can provide custom colors on davit crane bases or nearly any piece of equipment you need from us. Whether it is safety yellow or a different color that complies with the safety standards onboard your rig, we are happy to provide marine-grade epoxy finishes to match any color on the RAL color scale.

Parts and Service

Service parts can be obtained directly from the Thern factory by contacting Thern Customer Service at 800-843-7648.

Please contact the Thern Customer Service Department at 800-843-7648 with all repair and service inquiries. Our Customer Service Representatives will determine the best course of action to be taken to repair your winch or crane.

All Thern products carry a two-year limited warranty. Thern, Inc. warrants its products against defects in material or workmanship for two years from the original date of purchase.

The reducer on the 4WP2 Series holds 44 oz. of Mobilgear 630 or Mobilgear 600 XP 220 gear oil.

The reducer on the 477 Series holds 92 oz. of Mobilgear 630 or Mobilgear 600 XP 220 gear oil.

Nearly all failures reported with this symptom have failed due to the wire rope being overwound rather than underwound. Overwinding the wire rope forces the worm shaft in the reducer up into the bottom of the motor adapter plate, and over time the large helical gear on top of the worm gear wears into the adapter plate. This misalignment will cause premature failure of the upper bearing and other related components.

Product Comparisons

An aluminum davit crane, while lightweight and corrosion resistant in some environments, sacrifices a significant amount of lifting capacity due to the physical properties of aluminum. A stainless-steel davit crane, while somewhat heavier, provides the ultimate solution in corrosion resistance and lifting capacity.

With manual lifting equipment (such as a hand winch) the work is being done by the operator that is turning the handle of the winch. With electric lifting equipment, the electric motor does the work to turn the drum and spool the lifting rope. Thern offers a variety of both electric and manual lifting equipment.

An air tugger winch is powered pneumatically and designed for maritime use. An electric tugger winch is powered by electricity. If the load is higher or needs to move at faster speeds, then an electric winch may be better suited for the job.

A portable davit crane is designed so that it can be easily disassembled and moved to a different location and reassembled for lifting operations. Generally, stationary davit cranes offer the benefit of longer reach over a portable davit crane of comparable capacity. Thern offers a variety of both portable and stationary davit cranes with different lifting capacities.

An electric davit hoist requires an electrical input and uses an electric motor to turn the drum spooling the wire rope. A hydraulic hoist requires pressurized hydraulic fluid (typically from a hydraulic power unit) as input for a hydraulic motor, which turns the winch drum to spool the wire rope.

The difference between an electric hoist and an electric winch is that a hoist refers to a pulling device that lifts vertically with a wire rope or chain. Many people think of a winch as a device that pulls horizontally, when in fact, Thern winches can be placed in virtually any orientation (floor mounted, wall mounted, or underhung) and can pull both horizontally and vertically when properly equipped. Electric hoists will require an automatic brake for vertical lifting applications, while winches for horizontal pulls would not necessarily require a brake. Please reach out to our sales staff to discuss your project and the best solution to fit your needs.

If the weight, height, and reach requirements fit within a Thern davit crane capacity, a davit crane will be easier to install, operate, maintain, and is generally more affordable. Additionally, many of Thern’s davit cranes are more portable than a motorized jib crane. If you buy numerous bases, you can move the cranes to different locations to solve multiple lifting applications with just one crane.

https://thern.com/blog/davit-crane-vs-jib-crane-a-breakdown/

A gantry crane and davit crane often serve very different functions, but there are times that a davit can serve the same function when equipped with a rolling base.

Product Questions

In addition to all winch safety, which includes air winch safety, best practices are to:

  • Read the owner’s manual
  • Make sure the winch is securely mounted
  • Make sure supply lines are in good shape and are secure
  • Make sure the FRL is installed and in good shape
  • Install mufflers to reduce sound level. Mufflers with a filter element can be installed to reduce oil misting for the motor lubrication.
  • Install a shutoff valve
  • Use controls with an estop if the shut off valve is not within reach of the operator
  • Install a drum guard

Thern has several davit crane models that are appropriate for rooftop applications. Whether you are looking for a rooftop davit crane or a rooftop crane hoist, Thern can offer you long-lift solutions for servicing HVAC equipment or other applications.

Thern offers 20,000 lb winches and 40,000 lb winches. Depending on the speed required and allowable footprint, Thern offers several styles of winches, including 4HS, 4HPF, 4HBP, and 4BP. These winches are offered in a range of voltages and can be powered hydraulically.

Thern offers winches and hoists with capacities up to 100,000 pounds. Our 5,000 lb electric hoists can come in manual spur gear designs, as well as pneumatic and hydraulic. Check out our M452B, M492B, as well as our 4HS, 4HWF, 4HPF, and 4WS models.

Thern offers more than one type of a stainless-steel hand winch with a brake. The M4042PBSS model with a capacity of 1,000 pounds and the M4312PBSS model with a capacity of 2,000 pounds. Both have a frame and drum that are constructed with stainless steel and come standard with an automatic Weston-style brake.

Thern offers a variety of air winches or air-powered winches with capacities up to 37,000 pounds. These air winches can be referred to as pneumatic winches or air tuggers. Check out our Big Red, Mini TA Series, 4771 Series, as well as our C Series. If you’re unable to find what you are looking for, we can design a custom air-powered winch specialized to fit your application.

Thern manufactures a variety of compact hand winches and vertical-lift hand winches suitable for both vertical lifting and horizontal pulling applications. These include both spur gear and worm gear models that accommodate a variety of distance and load requirements. Thern also offers a hand winch that can be drill driven.

Thern offers a variety of lifting equipment parts such as wire ropes, hooks, sheaves, headache balls, vertical lead blocks, and other lifting equipment.

Thern offers multiple solutions from material handling lifting equipment to a conveyor belt pulling winch. We even provide a railcar moving winch. We can design a solution specific to your application. The engineering team at Thern can customize virtually any winch in our lineup to accommodate specific speed and control requirements. We can also accommodate site-specific variables such as grade, curvature, and distance. See our online portfolio for some of the most challenging and unique applications we’ve solved for our customers.

Thern provides winches for a variety of mining applications. Mine winches can take on several tasks from MRO to cart pulling to conveyor take-up and tensioning. Some of our customers utilize our products for drag lines and dredging, while others will use them for shaft sinking and plumb bobs.

Thern offers a variety of lifting solutions that meet ATEX requirements for explosive atmospheres. Just tell us the hazard class/environment the hoist, winch, and controls will be exposed to, and we can design an explosion-proof hoist or system to accommodate it.

Thern offers much more than just wall-mounted electric winches. Many of Thern’s portable and fixed-mount winches are suitable for mounting in different orientations, including floor, wall, and ceiling.

Several of Thern’s standard crane models can be used as a small vehicle-mounted crane. Additionally, Thern’s Workmate, a hitch-mount davit crane base, was specially designed to be compatible with a standard 2” receiver hitch. The Workmate allows customers to have a crane attachment for a truck, and it can be situated on the ground behind or to the side of the associated vehicle.

Technical Questions

Fleet angle is the angle between the wire rope and an imaginary line extending perpendicular to the drum. The fleet angle varies with the distance between the lead sheave and the drum. Using the correct fleet angle of wire rope will ensure your winch is operating at its full capacity and not causing undue wear.

Due to the substantial amount of difference between the components used in these two styles of spur gear hand winches, it is not cost effective to do this type of conversion.

Please consult with Thern, Inc. for approval before attempting this conversion. Any conversion attempted without Thern’s approval will alter the finished product from its original design and could void the warranty.

Water / Wastewater

Aerator / Dredge-Positioning Winches

Please answer these questions, so we can help you determine the right electric winch for your business: How many aerators are on the winching line, and what direction are they thrusting? What is the thrust force of the aerator?

Any voltage is available (115v, 230v, 460v, etc.) for electric winches, including single phase or three phase, and 50 or 60 hertz.

An electric winch brake is only required in a lifting application which includes pulling up an incline. An electric winch brake is not required in a horizontal pulling application/flat surface.

Yes, we will need to know the required voltage/hertz along with the Class, Group, and Division of the environment, so we can source the appropriate motor for your electric winch.

The answer is, “It depends.” Most Thern products are not rated for lifting people or things over people, and our standard davit cranes and winches are designed for lifting material only. That said, we offer a line of rescue-rated davit cranes that can be incorporated into your safety plan. Not to be confused with personnel-rated systems, the Thern rescue-rated davit cranes can be used to safely and quickly recover injured or disabled personnel.

When properly equipped, the power electric winch can move the aerator/dredge in one or both directions.

Bar Screen Winches

When properly equipped, an electric winch can move the bar screen in one or both directions.

Any voltage is available (115v, 230v, 460v, etc.) for electric winches, including single phase or three phase, and 50 or 60 hertz. 

An electric winch brake is only required in a lifting application which includes pulling up an incline. An electric winch brake is not required in a horizontal pulling application/flat surface.

Yes, we will need to know the required voltage/hertz along with the Class, Group, and Division of the environment, so we can source the appropriate motor for your electric winch.

The answer is, “It depends.” Most Thern products are not rated for lifting people or things over people, and our standard davit cranes and winches are designed for lifting material only. That said, we offer a line of rescue-rated davit cranes that can be incorporated into your safety plan. Not to be confused with personnel-rated systems, the Thern rescue-rated davit cranes can be used to safely and quickly recover injured or disabled personnel.

Dumpster Cart-Pulling Winches

The maximum weight of the dumpster cart when it is completely full ensures that the electric winch is sized correctly.

When properly equipped, the power electric winch can move the dumpster cart in one or both directions.

Any voltage is available (115v, 230v, 460v, etc.) for electric winches, including single phase or three phase, and 50 or 60 hertz.

An electric winch brake is only required in a lifting application which includes pulling up an incline. An electric winch brake is not required in a horizontal pulling application/flat surface.

Yes, we will need to know the required voltage/hertz along with the Class, Group, and Division of the environment, so we can source the appropriate motor for your electric winch.

The answer is, “It depends.” Most Thern products are not rated for lifting people or things over people, and our standard davit cranes and winches are designed for lifting material only. That said, we offer a line of rescue-rated davit cranes that can be incorporated into your safety plan. Not to be confused with personnel-rated systems, the Thern rescue-rated davit cranes can be used to safely and quickly recover injured or disabled personnel.

Pump Hoists and Mixer Lifts

To determine the best davit crane for your site, we’ll need to know the maximum load, horizontal reach, and hook height required to lift the load.

It is up to the customer to make the ultimate decision. Thern suggests an electric winch if the davit crane system is being used on a regular basis. However, if the davit crane system is only being used once a year for annual maintenance, it may be more cost-effective to purchase a manual winch.

An epoxy finish is recommended for davit cranes and electric winches over a standard enamel finish as it provides superior corrosion resistance in the harsh atmospheres common in water/wastewater applications.

The effort required to adjust the screw-jack while under load for davit crane systems can be greater than what is ergonomically appropriate. For this reason, Thern does not recommend making boom angle adjustments under load.

No. Drill driving a spur gear hand winch is not recommended due to the heat and wear generated during operation, which can shorten the life of the winch. Thern offers two worm gear manual winch options that can be drill driven. These worm gear winches are housed in an oil bath gear case, which dissipates the heat generated by drill-drive operation.

The 5PT30 davit crane is offered with either a boom brace or a screw-jack. There are specific part numbers for both options.

The handle is unable to be relocated from its original position. Other options are to use a worm gear winch where the handle is on the back of the winch/can be drill driven or an electric winch option.

Yes, we will need to know the required voltage/hertz along with the Class, Group, and Division of the environment, so we can source the appropriate motor for your electric winch.

Yes, an integral brake is provided on the winch for any lifting application with a davit crane system.

Yes, a portable davit crane can be used as a stationary davit crane. A portable crane does need to be moved to other davit crane base locations if the application does not require it.

This is to aid in the portability of the davit crane from one application to the next. Rather than unhooking the wire rope from the load, you can simply disconnect the wire rope from the winch using the quick disconnect feature, hook it in the key-hole slot on the gusset of the base or an optional rope keeper, and move the crane to a different base location. This feature improves the safety and efficiency of operations by allowing the wire rope assemblies to remain connected to the load and eliminates “fishing” in less-than-optimal conditions.

Typically, both items do not need to be used at the same time. The cable spool is typically used in mixer maintenance applications, and the wire rope keeper is used in all other applications.

The answer is, “It depends.” Most Thern products are not rated for lifting people or things over people, and our standard davit cranes and winches are designed for lifting material only. That said, we offer a line of rescue-rated davit cranes that can be incorporated into your safety plan. Not to be confused with personnel-rated systems, the Thern rescue-rated davit cranes can be used to safely and quickly recover injured or disabled personnel.

UV Panel Hoists

To determine the best davit crane for your site, we’ll need to know the maximum load, horizontal reach, and hook height required to lift the load.

It is up to the customer to make the ultimate decision. Thern suggests an electric winch if the davit crane system is being used on a regular basis. However, if the davit crane system is only being used once a year for annual maintenance, it may be more cost-effective to purchase a manual winch.

An epoxy finish is recommended for davit cranes and electric winches over a standard enamel finish as it provides superior corrosion resistance in the harsh atmospheres common in water/wastewater applications.

The effort required to adjust the screw-jack while under load for davit crane systems can be greater than what is ergonomically appropriate. For this reason, Thern does not recommend making boom angle adjustments under load.

No. Drill driving a spur gear hand winch is not recommended due to the heat and wear generated during operation, which can shorten the life of the winch. Thern offers two worm gear manual winch options that can be drill driven. These worm gear winches are housed in an oil bath gear case, which dissipates the heat generated by drill-drive operation.

The 5PT30 davit crane is offered with either a boom brace or a screw-jack. There are specific part numbers for both options.

The handle is unable to be relocated from its original position. Other options are to use a worm gear winch where the handle is on the back of the winch/can be drill driven or an electric winch option.

Yes, we will need to know the required voltage/hertz along with the Class, Group, and Division of the environment, so we can source the appropriate motor for your electric winch.

Yes, an integral brake is provided on the winch for any lifting application with a davit crane system.

Yes, a portable davit crane can be used as a stationary davit crane. A portable crane does need to be moved to other davit crane base locations if the application does not require it.

This is to aid in the portability of the davit crane from one application to the next. Rather than unhooking the wire rope from the load, you can simply disconnect the wire rope from the winch using the quick disconnect feature, hook it in the key-hole slot on the gusset of the base or an optional rope keeper, and move the crane to a different base location. This feature improves the safety and efficiency of operations by allowing the wire rope assemblies to remain connected to the load and eliminates “fishing” in less-than-optimal conditions.

Typically, both items do not need to be used at the same time. The cable spool is typically used in mixer maintenance applications, and the wire rope keeper is used in all other applications.

The answer is, “It depends.” Most Thern products are not rated for lifting people or things over people, and our standard davit cranes and winches are designed for lifting material only. That said, we offer a line of rescue-rated davit cranes that can be incorporated into your safety plan. Not to be confused with personnel-rated systems, the Thern rescue-rated davit cranes can be used to safely and quickly recover injured or disabled personnel.

Workshop / Maintenance Cranes

To determine the best davit crane for your site, we’ll need to know the maximum load, horizontal reach, and hook height required to lift the load.

It is up to the customer to make the ultimate decision. Thern suggests an electric winch if the davit crane system is being used on a regular basis. However, if the davit crane system is only being used once a year for annual maintenance, it may be more cost-effective to purchase a manual winch.

An epoxy finish is recommended for davit cranes and electric winches over a standard enamel finish as it provides superior corrosion resistance in the harsh atmospheres common in water/wastewater applications.

The effort required to adjust the screw-jack while under load for davit crane systems can be greater than what is ergonomically appropriate. For this reason, Thern does not recommend making boom angle adjustments under load.

No. Drill driving a spur gear hand winch is not recommended due to the heat and wear generated during operation, which can shorten the life of the winch. Thern offers two worm gear manual winch options that can be drill driven. These worm gear winches are housed in an oil bath gear case, which dissipates the heat generated by drill-drive operation.

The 5PT30 davit crane is offered with either a boom brace or a screw-jack. There are specific part numbers for both options.

The handle is unable to be relocated from its original position. Other options are to use a worm gear winch where the handle is on the back of the winch/can be drill driven or an electric winch option.

Yes, we will need to know the required voltage/hertz along with the Class, Group, and Division of the environment, so we can source the appropriate motor for your electric winch.

Yes, an integral brake is provided on the winch for any lifting application with a davit crane system.

Yes, a portable davit crane can be used as a stationary davit crane. A portable crane does need to be moved to other davit crane base locations if the application does not require it.

This is to aid in the portability of the davit crane from one application to the next. Rather than unhooking the wire rope from the load, you can simply disconnect the wire rope from the winch using the quick disconnect feature, hook it in the key-hole slot on the gusset of the base or an optional rope keeper, and move the crane to a different base location. This feature improves the safety and efficiency of operations by allowing the wire rope assemblies to remain connected to the load and eliminates “fishing” in less-than-optimal conditions.

Typically, both items do not need to be used at the same time. The cable spool is typically used in mixer maintenance applications, and the wire rope keeper is used in all other applications.

The answer is, “It depends.” Most Thern products are not rated for lifting people or things over people, and our standard davit cranes and winches are designed for lifting material only. That said, we offer a line of rescue-rated davit cranes that can be incorporated into your safety plan. Not to be confused with personnel-rated systems, the Thern rescue-rated davit cranes can be used to safely and quickly recover injured or disabled personnel.

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