FAQs

• Is Side-Power and Sleipner the same product?

  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.

• Where do I find spare parts?

  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.

• Where do I find spare parts for older thrusters?

  Please download this PDF that contains spare parts for DC electric thrusters produced after 1998. 

• Where can I download manuals?

  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.

THRUSTER INSTALLATION

• Why does Sleipner declare thrust at 10.5 volts – whereas others state thrust at 12 volts?

  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.

• Can I use LiFePO4, Lithium or Lithium-ion batteries for my thrusters?

  Yes, you can, but not without taking some precautions. Sleipner produces two product lines of thrusters that will work well with high-capacity batteries and one product line which should be used with caution in combination with LiFePO4, Lithium, Li-ion, or similar batteries, which may be capable of delivering higher voltage under load than traditional batteries (such as lead-acid, AGM, gel or similar).

  • All Sleipner proportional thrusters will work well with Li-ion or LiFePO4 batteries, as the included PPC unit will control the output voltage to a safe level for the thruster. Make sure, though, that you actually get a good battery intended for maritime use. NB - make sure you have the latest embedded software installed.
     
  • All Sleipner eVision thrusters have built-in functionality to limit the maximum voltage delivered to the thruster. Again, make sure your battery is intended for maritime use.
     
  • Traditional DC on/off thrusters may be damaged or have a reduced life expectancy if operated at voltage levels outside their specifications.

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

• Are Lithium-ion (Li-ion), LiFePO4 or Lithium batteries a good solution for thruster battery bank?

  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.

• Can the thruster cause the BMS to disconnect the batteries?

  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.

• What is the S-link control system?

  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:

  • It is round and compact and has 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

• How do I install a thruster in the stern?

  All 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. 

• Can I install a thruster in a wet position of the boat?

  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.

• Can I install a thruster in the engine room of boat?

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

• The water flow from my thruster hits the hull or trim tabs. What can I do?

  Stern tunnels installed too high might cause water to hit the hull or trim tabs. 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.

• What’s the minimum and maximum length of a thruster tunnel?

  If the tunnel is too short, water will circulate from one side of the tunnel to the other and reduce thrust. 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.

• How much thrust does my boat need?

  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.

• Tunnel installation and thruster positioning?

  Where should the thruster be positioned?

  • 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.

• How deep under the waterline must my thruster tunnel be?

  We recommend installing the thruster as deep as possible and at least 3/4x the tunnel diameter below the waterline. 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.

• Why does the Q-prop skew back propeller reduce noise?

  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.

• Can I have multiple control positions for one thruster?

  Yes, multiple thruster control panels can be installed with all thruster systems. 

• Can other brands of marine dashboard/engine/remote controllers be utilized to operate Sleipner thrusters?

  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.

• What is IPC (Intelligent Power Control)?

  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.

• Is it possible to upgrade/modernize my existing thruster?

  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. 

THRUSTER OPERATION & TROUBLESHOOTING

• My electrical thruster does not operate?

  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.
• My thruster control panel will not switch on?

  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. 

• I don’t get enough power from my thruster – what can be the reasons?

  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.
    • Measure the voltage directly at the motor
    • 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.
• The remote control for my thruster fails to operate?

  Check the battery in the transmitter.
  Ensure there is power at the receiver, and that the transmitter and receiver are paired.

   

• My thruster is losing effect?

  The common reasons for thruster loss of effect are either lack of power or high current draw. Please do the following: 

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

  If still losing effect, check if the tunnel is dirty and if the propellers have excessive marine growth because of incorrectly handed/fitted propellers. This might have affected or damaged the propellers. 

THRUSTER MAINTENANCE

• What is cavitation, and how does it occur?

  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 aeriated from the tunnel intake and through to its outlet. Usual causes: 

  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 (A9)
  3. Increased tunnel and thruster noise level
  4. Increased wear and tear on the thruster components and system reducing its life span.
• Does my thruster need antifouling, and what type should I use?

  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.

• Where can I get anodes for my thruster?

  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. 

• What is galvanic corrosion?

  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. 

• Where can I get spare parts for my thruster?

  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.

• Do I need to change the oil on my thruster's gear leg?

  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. 
   

• My thruster is cavitating. What to do?

  Cavitation appears when the thruster propeller draws air. This is very detrimental for thrust and the proper functionality of your thruster.

  • • 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.

• The windlass panel will not turn on?

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

• Can I use an anchor chain combined with the Midi windlass?

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

• The rope will not go out by itself?

  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.

• The “end stop” function of the windlass is not working?

  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).
• The remote control of my windlass fails to operate?

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

• How long is the warranty of a Sleipner product?

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

• Who shall I contact with a warranty claim?

  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.