FAQ

Yes, information should then be shared to all MFD’s connected to the same switch.

Installation manuals, user manuals, technical drawings and spare part lists can be downloaded from our website.  You can find all current products under Products and download what you need in the documents-tab.

Yes. Up until 2021, Sleipner used a dual branding strategy on their products. In some markets, the Sleipner name was used – whereas in other markets, the name Side-Power was used. In 2021 a decision was taken only to use the Sleipner name going forward.

A Sleipner product is covered by a two-year guarantee. Refer to your manual for detailed information or read our Warranty Statement here. 

If you have a problem with a Sleipner product, please contact the point of sales where you originally purchased your Sleipner product. If you are uncertain where it was purchased, please contact your nearest Sleipner dealer.

Your Sleipner dealer has dedicated access to our helpdesk system and is your representative towards us as the manufacturer.

The special 5-blade design of the Q-prop makes sure that there is always a part of a propeller blade that is “covering” the gear leg of the thruster. Before the tip of the propeller is clear of the gear leg, the lower half of the following blade covers the gear leg. On traditional 4 bladed propellers, you get a water pulse that hits the gear leg each time the gap between the 4 propeller blades passes the gear leg. This create noise and cavitation.

Unlike most thruster manufacturers, Sleipner bases its products' thrust (kg) on a realistic, achievable voltage in real-life conditions rather than on theoretical thrust measured under ideal laboratory conditions. 

The electric motor's voltage level will determine the actual thrust output you get from a thruster system. Unless your onboard electrical system is custom-built to maintain voltage under very high amperage loads, resistance will somewhat reduce the voltage reaching the electric motor, resulting in lower thrust output accordingly to the drop in voltage. 

Power cables, fuses, main power switches, connections, etc., create resistance, effectively reducing voltage. If you calculate the thrust needed for your vessel and do not factor in the typical drop in voltage in most systems, you run the risk of a significantly underpowered thruster unit. 

After years of thorough on-water testing, Sleipner is aware that statistically, on a perfectly installed electrical system, due to voltage drop and current draw, no more than 10.5V will be measured on the thruster 12V system or 21V on a 24V system. 

As an example, the Sleipner DC Electric Tunnel Thruster SE100 is tested to provide 100 kg of thrust at 10,5V. Feed it with 12V, and it delivers 116 kg of thrust. 

Based upon our decades of experience, Sleipner recommends using 10,5/21V as reference values when calculating the right thruster size. If you choose your thruster based upon the unrealistically 12V thrust level, you will most likely lack the necessary power in rough conditions when you need it. 

Sleipner lists both values only for comparison reasons, as some other manufacturers only list 12V/24V thrust output. 

When comparing Sleipner thrusters with other brands, you can generally go down a size when retrofitting a Sleipner product. 

Learn more about thruster sizing here.

Please see our recommendations in this Youtube video. 

The thruster should be positioned as far forward as possible. This is important as the relative distance from the boats pivot point to the thruster installation point will change the actual thrust of the boat. The further away from the pivot point of the boat – the larger the thrust.

The thruster shall be positioned as deep as possible for two reasons;

• So that it does not suck air from the surface, causing cavitation which will significantly reduce thrust and create noise
• To increase the water pressure so that the propeller has a firm substance to work with for maximum performance. We recommend at least ¾ x the tunnel diameter below the surface and more is better. It is never recommended to go less than ½ x the tunnel diameter below the water surface.

In reality it is often a compromise between how far forward you want the thruster to maximise the force arm from the pivot point of the boat – and how deep you can position the thruster.

It is also a good advice on high speed boats to consider that the tunnels can come out of the water at high speed, but as slamming loads can be overcome by working with the tunnel installation to deflect the water.

Spare parts are listed in a tab named 'Spare Parts' under each product.

For example, if you need to find a spare part for your thruster model SE60, go to Products> Thruster Systems> Thrusters and find SE60 in the product overview. Or search for "SE60" in the search bar.

At the bottom of the SE60 product page, you will find a separate tab called Spare Parts.

Spare parts can be purchased at your local dealer. 

Please download this PDF that contains spare parts for discontinued Side-Power and Sleipner DC electric thrusters produced after 1998. 

For our standard Sleipner DC powered thrusters, the model number can be found on the front cover and the serial number on the badge on the electric motor. 

On our website you will find exploded views and spare part lists for all our thrusters. Your closest dealer will be able to order and install the spare parts you need.

You will find exploded views and spare part lists for all our thrusters on our website, which includes anodes. Your closest Sleipner dealer will be able to assist and support as deemed necessary and supply the correct anodes for your thruster. 

Sleipner recommends that the thrusters are connected to a battery bank that is not protected by a Battery Management System (BMS). Typically this means lead-acid, AGM, gel, or similar kinds of batteries. This is important because thrusters draw a lot of currents quickly, and the high amp draw may lead the BMS system to think that there is an issue with the system and consequently disconnect the batteries from the circuit, in which case you would lose maneuverability.

If you have Lithium batteries powering your thrusters, the best advice we can give you is to check the actual voltage measured on the thrusters during operation. Sleipner thrusters are designed to operate within a specific voltage range, and as long as you are within these boundaries, it doesn’t matter for the thruster if the current is delivered by this or that battery pack.

It may also be a very good idea to check the actual current drawn from the battery during full power at the thruster to see that you are not at the limit for the BMS to avoid sudden loss of maneuverability if the BMS disconnects the battery.

With installations where the battery pack is far from the thruster, the higher voltage delivered by LiFePO4 or similar batteries might not be a problem as you will experience a voltage drop through the long cables.

Always make sure you measure your voltage on the thruster to avoid the risk of early thruster wear.

As battery tehcnology is changing rapidly, we always recommend consulting a professional battery supplier. 

Disclaimer: Ensure battery/energy source is installed according to CE/ISO current rules and regulations and by licensed electricians.

If the tunnel is too short, water will circulate from one side of the tunnel to the other and reduce thrust. The gearleg might also be at risk from water passing through the tunnel at high speeds during driving, turning the propeller(s) at very high speeds. Note that tunnel openings must be rounded and with a deflector to direct water out from the tunnels back wall. Please see installation manuals for proper tunnel installation.

If the tunnel is too long, it creates too much friction and reduce thrust and you might want to increase the thruster size to compensate.

Maximum and minimum tunnel lengths for each thruster can be found in their manuals, which can be downloaded from this website.

S-link is a Sleipner CAN BUS based control system with full intelligent communication between all devices within the system, much like a computer network. It is used for all retract thrusters and Pro thrusters with a DC control system.

Main advantages include:

• Round, compact and waterproof plugs with unique keying and color coding to avoid faulty hookups. 

• An unlimited number of commands or information transfer on a single cable.

• It has user feedback to panel

• Intelligent troubleshooting

This is a unique patented Sleipner safety feature supplied with all standard (on/off) DC electric Sleipner thrusters. The IPC functionality provides two unique features: 

1) It will detect "flapping" of the solenoid (typically caused by badly charged batteries that are subject to a huge current draw and voltage drop when the thruster motor is engaged), and will stop trying to run the thruster, preventing excess solenoid contact tip wear and dramatically reducing the risk for a weld-in situation of the solenoid. A 'weld in' (run away) situation is when a thruster continues operating without a signal from the operator at the control panel. 

2) Even if the solenoid has a weld-in situation, which even with the IPC prevention actions is still possible, as all mechanical switches can weld-in at a point, the unique IPC function will STOP THE THRUSTER, without active action by the operator. This will give the operator time to locate and Select OFF on the thruster system Isolation/Main Switch.

Understanding how corrosion and sacrificial anodes work on board a boat is vital to maintain your thrusters' life expectancy. It is a complicated subject about which we have written a detailed guide that can be found here. 

Cavitation is a phenomenon in which the reduction of pressure to or below the liquid's vapor pressure leads to the formation of small vapor-filled cavities in the liquid. The most common examples of this kind of wear are to pump impellers and bends, where a sudden change in the direction of liquid occurs.

Cavitation occurs in a thruster tunnel when water flow is disturbed and aerated from the tunnel intake and through to its outlet.

Usual causes are: 

1. Tunnel installed too high and close to the water line – thruster propellers draw in air from the water surface.
2. Sharp tunnel edges or obstacles at or in the tunnel intakes create disturbed water flow entering the propeller(s).
3. Damaged, incorrectly installed, or handed propeller(s)
4. The tunnel, gear-leg, and propeller(s) surfaces are dirty or subject to heavy marine growth.
5. Tunnel guards or grids.
   
   

Cavitation effect:

1. Reduced water flow and thruster effect.
2. High current draw
3. Increased tunnel and thruster noise level
4. Increased wear and tear on the thruster components and system reducing its life span.

What can be done:

• Consider upgrading to a proportional thruster system (all Sleipners thrusters can be upgraded). This gives you the opportunity to use the thruster at variable speed and to increase the thrust gradually, significantly reducing the risk of cavitation.
• If you have an old propeller, consider upgrading to the Q-prop, which is designed to remove cavitation (and noise) as it reduce pulsing between the propeller blades and the gear leg which can create noise and cavitation.
• Verify that there are no sharp edges on the tunnel thrusters. We have made a video which shows the difference on rounded edges of a tunnel and sharp tunnel edges which can be found here.
• For stern thrusters that are installed to close to the water line and thereby draws air into the tunnel from the surface, adding cowls could be and effective solution. 

If you suspect cavitation in either your bow or stern thruster, we recommend contacting an experienced installer who can assist in finding optimal solutions to bring performance back to expected levels. 

A Lithium or Li-ion battery may maintain a significantly higher voltage and higher current under load than a lead-acid, gel or AGM battery. This will provide significantly more power to the thruster motor and give some undesired side effects:

-      The propeller will rotate significantly faster and with higher power than what they are designed for, increasing the risk of cavitation and following damages in the tunnel and at the thruster.

-      The thruster risks overheating and will have shorter run times. This can cause the thruster to stop in the middle of a maneuver.

-      Over time, the thruster may be damaged and you may have a reduced life expectancy.

Sleipners speed controlled thrusters will not be impacted by Lithium, Li-ion or similar battery times providing a steady high voltage.

Disclaimer: Ensure battery/energy source is installed according to CE/ISO current rules and regulations and by licensed electricians.

1. Check the battery in the transmitter.
2. Ensure there is power at the receiver, and that the transmitter and receiver are paired. (Check installation manual for pairing procedure if necessary)

With the interest of safety prioritized preventing accidental use, all Sleipner electrical thrusters Control Panels have double 'ON' push buttons. To activate the control panel,  you must press both "ON" buttons simultaneously. If your control panel still doesn't switch on, please check if there is electrical power available to the control panel. 

The common reasons for thruster loss of thrust are either lack of power or high current draw. Please do the following (Note: we strongly recommend using a professional for all electric check points): 

• Check battery bank charge.
• Check for excessive voltage drop in the cable runs.
• Check for loose cable connections. 

If still losing thrust, check if the tunnel and/or the propellers have excessive marine growth so that both water flow and propellers runs smoothly. Also inspect propellers for damage and ensure they are firmly fitted to the propeller shaft while turning. 

There can be several reasons why a thruster fails to operate, but before contacting a service point, we suggest you check the following:

• Make sure the battery isolation/main switch is selected 'ON'.
• Check that the system fuse is fitted and not blown.
• Check that power is available from the battery bank.
• Make sure the control panel has power (Panel LED or window lights up).
• Acknowledge and record any alarms if feasible.

A solution is adding cowls (sold separately) to your stern tunnel to prevent water cavitation. The cowls are perfect for deflecting water away from obstacles such as stern drives, bathing platform stanchions, trim-tabs, or other transom fittings.

Please note that adding cowls reduces the actual thrust by a few percent, so it is not recommended to add them if not needed. 

Yes, it is possible to upgrade/modernize/repair most older models of thrusters with the following kits, if relevant:

1. Q - propeller kits (the five-blade Q propellers reduce cavitation, noise and more effective than the earlier four-blade standard propeller).
2. IPC (Intelligent Power Controller) electronic control box, which is the only alternative now available for pre-2005 standard (on/off) DC thrusters 
3. Upgrading to PRO, utilizing the Sleipner S-link (CAN BUS) control system giving you variable speed control of your thruster.
4. Many thrusters are delivered in various power output for the same tunnel diameter. If you want more power, there might be a more powerful unit available that will fit your current tunnel. Check the model range for options or contact your local dealer for guidance. 
5. (NEW2023) PRO (speed controlled) models can be upgraded with the new E-series motors launched in 2022. These motors are lighter and very efficient, IPx7 and have integrated speed control as standard. These motors are up to 40% more compact than previous motors. So for installations that can not fit a bigger motor but lacks performance, these new motors might the answer to how you can get more thrust without the need of more internal space. 

Please read more here. 

The most common reasons for not getting enough power out of your thrusters are:

• Low voltage to the motor. The thruster shall deliver the declared thrust when operating at 10.5 Volts. If the distance between the battery and the thruster is long, if the battery is old or if the battery cables are to thin, it is usual to have less than 10.5V at the motor.
  
  1) Measure the voltage directly at the motor
  2) If low voltage, consider installing a dedicated thruster battery close to the thruster or increase the cable dimensions.
  
  
• The efficiency is reduced by marine growth on the propeller, gear leg or in the tunnel. Check that the gear leg, tunnel and propeller is free of growth and apply antifouling.
• Cavitation, which means that the thruster draws air which extremely damaging for thrust. Read more below on how to reduce cavitation:

Consider upgrading to a PRO thruster system (all Sleipners thrusters can be upgraded). This gives you the opportunity to use the thruster at variable speed and to increase the thrust gradually, significantly reducing the risk of cavitation.

If you have an old propeller, consider upgrading to the Q-prop, which is designed to remove cavitation (and noise) as it reduce pulsing between the propeller blades and the gear leg which can create noise and cavitation.

Verify that there are no sharp edges on the tunnel thrusters. We have made a video which shows the difference on rounded edges of a tunnel and sharp tunnel edges which can be found here.

We recommend to replace the anode before every season, or when half the anode has eroded. Always use a sealant or thread glue on the holding screw to ensure that it does not fall off.

If you want to read more about corrosion in general, please see our "Boaters guide to corrosion"

How much thrust your boat needs generally depends on its size, the thruster's installation point, the surface affected by the wind – and your expectations as to how fast you want the boat to react. 

Sleipner has the world's largest database on expected thruster performance on different boats and has developed proprietary software that can run simulations. Based on this we are giving some general recommendations on our website. You can read more about thruster sizing here. 

For help to right-size a thruster to your boat, we recommend contacting your local Sleipner dealer.

Most Sleipner tunnel thrusters can be utilized as stern thrusters. This is achieved by using a stern-thruster tunnel kit, an external protruding tunnel module attached to the boat's transom. Retractable thrusters are also an excellent option, both for sailboats and motorboats. Sleipner also manufactures purpose-built compact external units that require minimal internal space, allowing installations in boats that normally cannot fit a stern thruster because of lack of space. Explore the Sleipner thruster-range on our website or contact your local Sleipner dealer for more information. 

Please see our video instruction on Youtube. 

We recommend installing the thruster as deep as possible and at least 3/4x the tunnel diameter below the waterline (eg 300mm x 0,75 = 225mm minimum).

On some boats this might be impossible due to the positioning of other equipment onboard and for the lack of better options, it might only be possible to get the top of the tunnel ½ x the tunnel diameter below the waterline. Notice though that this increase the risk of cavitation.

For some boat types, external or retractable thruster models might be a better solution if it is difficult to place the tunnel deep enough. 

We always recommend to seek the advise of experienced installers for optimal results. 

The majority of Sleipner thruster gear-legs are pre-filled with oil during manufacture. Non-pre-filled thruster gear-legs require filling prior to installation and additional periodic oil change servicing. Please confer to your manual for details. 

Yes, in addition to using a Sleipner Control Panel using other brands of controllers is possible. Sleipner is cooperating with most of the world leaders that manufacture products in this field. Most have already integrated their products with our S-link (CAN BUS) protocol. This includes brands such as Volvo, Xenta, Cummings, Twin Disc, ZF, Aventics and Yanmar engine controllers and docking systems such as Dockmate and Yacht Controller.

All underwater equipment subject to marine growth apart from anodes, rubber boots, and seals must require antifouling. We do not supply antifouling but suggest you contact your harbormaster or local yacht club and seek advice regarding the best product you can legally use in your region.

Yes. Most engineers would tell you that it is not ideal for connecting the bow thrusters to a service bank protected by a Battery Management System. Thrusters are heavy consumers, and they may create sudden peaks in current draw, which again may cause the BMS to disconnect the batteries if the thruster draws more current than allowed. If this happens in the middle of a maneuver, you would be left without thrusters and may lose control of the boat.

Hence, Sleipner recommends that the thrusters be connected to a separate battery bank (that is not lithium) without a Battery Management System that can disconnect the batteries (and consequently the thrusters).

Disclaimer: Ensure battery/energy source is installed according to CE/ISO current rules and regulations and by licensed electricians.

No. The run commands are different, and PJC21x control panels do not support running HYD thrusters. For support of the combination of DC thrusters and HYD system for stabilizers, the PJC21x control panel will show hydraulic info like oil temp/pressure, but will not runn HYD thrusters.

PJC221, PJC222, PJC32x, PJX42x or similar control panels are required for operation of HYD thrusters

To ensure proper functioning and maintaining important safety features, we always recommend using original Sleipner control panels. 

Yes – but it needs to be Ignition Protected to avoid risks related to potential gasoline fumes in the engine room.

We always recommend that both bow and stern thrusters are mounted in a dry and well-ventilated compartment. Sleipner's thruster motors, electronic components, and wiring harnesses do not perform well when wet or corroded. They are neither water nor corrosion-proof and therefore need to be kept as dry as possible.

We supply ignition proof (IP) thrusters (spark-free) designed for petrol-driven yachts where ignition of petrol fumes is an issue. The IP thrusters can be appropriate for yachts where it is challenging to keep thruster compartments 100% dry. The IP thrusters are tested underwater to handle moisture and a little water shower now and again, but not completely immersed.

(Addition Feb 2023:) The new E-serie thrusters launched in 2022 also features the same characteristisc as IP thrusters, but in a more compact format and might allow installations in small areas where IP models have not previously fit.

On a Sleipner thruster system you can use several Sleipner Control Panels.

For example one in the cockpit, one on the fly bridge and one in the stern steering position.

Not necessarily. These systems typically come with a Battery Management System (BMS) that will disconnect the thruster in case of any issue with the battery (for instance, if the thruster draws more current than the BMS allows). Just imagine a sudden cut-out in the middle of a maneuver without any pre-warning.

At Sleipner, we recommend a solution with a simple, separate battery and without a disconnect BMS system (such as the lead acid bank frequently used for starting or similar). The helmsman will then be warned when the battery is getting low and feel that the thrusters are gradually losing power, which is significantly better than losing your thrusters without any pre-warning.

Disclaimer: Ensure battery/energy source is installed according to CE/ISO current rules and regulations and by licensed electricians.

Check the battery in the transmitter and that there is power to the receiver. 

In your windlass, there is an automatic sensor that recognize when the small copper rings on your anchor line pass through the sensor next to the gypsy.

• Verify that both copper rings remains intact at the end of your rope.
• Verify that your windlass is programmed directly (confer to the manual).

Please check if the systems battery main switch is switched on before trying again.

When used in salt water, salt crystals will dry out the rope and make it stiff. Try washing your anchor line in fresh water. We always recommend washing it in fresh water at the end of the season.

Also make sure to use original Sleipner lead rope, as these are calibrated specifically to the gypsys. 

Please see the manual and this Youtube video. 

No – the Midi windlass has a gypsy that is made for rope only. Please make sure you use original ropes with a lead core as these are specifically calibrated to the gypsy.