As the marine industry has evolved over the years, there’s been a continuous effort to make boats easier to control in any conditions.
In pursuit of this goal, all sorts of gimmicks have come and gone with various degrees of success. One thing that has stuck around, however, are thrusters.
In short, thrusters are additional propulsion systems used specifically for precise maneuvers in low-speed situations. These propellers move the boat sidewards as opposed to forward or aft.
The most common thrusters are bow thrusters, with the addition of stern thrusters giving the operator complete control while docking. Have you ever seen a boat walking sideways towards the dock? More than likely, there were both bow and stern thrusters at work there.
One of the leading manufacturers of thrusters is Sleipner (formerly Side-Power) Thrusters. In the post below, we’re going to look at the best 5 Sleipner bow thrusters for your boat.
A tunnel thruster is mounted in a tunnel through the hull of your vessel. Tunnel thrusters are the most common type of thruster due to the flush mounting of the equipment, which reduces drag.
The SEP300 PRO Tunnel bow/stern thruster is one of the more popular tunnel thrusters from Sleipner. This is a powerful thruster which provides up to 340kgs of thrust, making it suitable for vessels up to 100 feet.
Now that’s a lot of power for a thruster. The good news is that you don’t have to use all of that power every time, as the variable speed control (aka proportional control) allows you to control how much power you use with each thrust. This is a feature in all of Sleipners Pro model thrusters. This ultimately allows you to have complete control of your vessel without excessive noise or wear and tear on your thruster.
The twin counter-rotating propellers allow this thruster to be mounted in a narrower tunnel without sacrificing performance. This thruster can also be installed at an angle on the interior of the vessel, making it compatible with a variety of hull shapes.
This thruster is a great option if you need power for a larger vessel. If you’re happy to take your boat out in adverse conditions, you’ll need a powerful thruster you can rely on.
The variable speed control gives you complete control, and the plethora of safety features will give you countless worry-free hours docking your boat.
A retractable thruster lives inside the hull, with no part of the thruster protruding below the hull when it’s not in use. A gear leg will drop the thruster out of the bottom of the hull when it’s time to get to work.
The SRL80 Retractable bow/stern thruster from Sleipner deploys quickly with the push of a button. The 96 kgs of thrust is controlled by an on/off switch for simple use. The SRL80 also comes in a PRO model which includes proportional control.
A common feature of Sleipners mid-range models is the twin-propellers mounted in the tunnel. This allows better performance from your thruster without the need for a large diameter tunnel.
If you’re a performance boater, and any amount of drag is a concern, then a retractable thruster is the option for you. Retractable thrusters are also a great choice if you have a boat with a shallow draft where a tunnel mounted thruster would be ineffective.
When no other thruster will fit, an external bow thruster will. External bow thrusters are an excellent choice for sailboats, since space inside the hull is often tight. Additionally, the drag of the external thruster won’t have a significant effect on the low speeds typical of sailboats.
The SX50 External bow/stern Pod thruster from Sleipner couldn’t be more simple to install. Simply bolt it to the hull, minimal holes required. Although you should always consult a professional when doing through-hull work.
The hydrodynamic design of the thruster’s cover reduces drag, and actually allows you to install the thruster in the water flow without hindering performance. The fact that this thruster lives below the water line means it’s water-cooled, giving you longer run times with increased energy efficiency.
The smaller thruster range from Sleipner comes with a single propeller mounted inside the thruster tunnel. This allows the thruster to be much more compact, delivering all the benefits of a bow thruster to narrow hulled boats.
After the main engines and generators, your thrusters are going to be the biggest consumers of energy onboard. This energy can come from either AC or DC electricity, but there’s a third option too.
When you need a whole lot of power out of your thrusters, or you expect to run them for a long period of time, hydraulic power is a viable option. Since many recreational boats don’t have a hydraulic system, hydraulic thrusters are most often found on commercial vessels or larger recreational vessels.
The SH160 Tunnel bow/stern thruster hydraulic U14 is on the smaller side for hydraulic thrusters, making it perfect for non-commercial applications.
This tunnel mounted thruster boasts twin propellers, delivering more power more efficiently within a smaller diameter tunnel. The Pro model is equipped with proportional control, so you only need to use the necessary amount of power to achieve the result you’re looking for.
While this is a smaller hydraulic thruster, you’re still getting 160 kgs of thrust for vessels in the 11-19 meter range. It’s important to remember that most vessels in this size range won’t have a hydraulic system. If you do have a hydraulic system, however, this thruster will be an easy and effective added component to your hydraulic system.
AC power is the third power source for thrusters. AC power is mostly seen in commercial applications, although there are scenarios where AC power would make the most sense in a recreational environment too.
An example would be if you already have a hydraulic thruster in place and would like to add another thruster that you can use at the same time. The main engines might not be able to produce enough hydraulic pressure to run both thrusters at the same time. Therefore, an AC powered thruster would be a good option in this scenario since they’d be powered by the generators.
The SAC360 Tunnel bow/stern thruster from Sleipner is powered by AC power. It produces 360 kgs of continuous thrust. This means that this thruster can run continuously for long periods of time if needs be, thanks to the AC power.
This thruster is also adaptable in terms of how it’s mounted. It can be mounted at any angle that fits the hull of the boat and can even be installed horizontally. The twin counter-rotating propellers provide the most power in a small diameter tunnel for efficient use and run time.
It’s important to remember that AC motors are very bulky and heavy compared to hydraulic motors of the same power output, so this should be considered if space is tight.
After reading about all the options above, which thruster will you choose? There is a huge variety of thrusters out there that will fit pretty much any boat that’s been built. So whether you’re looking for minimal drag, maximum power, or a simple secret weapon to make your docking maneuvers extra smooth, there’s a thruster that will work for you.
When it comes to bigger modifications to your vessel, like adding or updating a bow thruster, it’s always best to go with a renowned brand with a solid reputation. Sleipner has been producing marine engines in Norway since 1908. So when you bring a Sleipner thruster on board, you know peace of mind is coming aboard with it.