Seawing is a towed hydro-generator. It allows you to recharge your boat’s batteries while you sail. It is connected to your boat by a flexible cable ensuring both the mechanical holding function and the electricity transfer function.
It is made up of an marine aluminum frame to which two counter-rotating propellers, a float and a stainless steel fin are attached. Sacrificial anodes are positioned on the propellers and on the fin to prevent corrosion problems. It weighs approximately 8 kg and its propellers have a diameter of 280 mm.
As soon as the boat speed exceeds 3 knots, the hydro-generator propellers start and charge the battery. The float coupled with the massive stainless steel fin allows the system to be positioned in the water. The 12° inclined fin allows the system to be maintained at an optimal depth over the entire operating speed range of the hydrogenerator.
System performance depends on several factors. Generally speaking, the faster the boat, the more production increases until a production ceiling is reached. The system can operate at 12, 24 or 48 Volts. However, the higher the voltage of your battery bank, the more the production ceiling of your hydro-generator is increased. The hydrogenerator is equipped as standard with 280 mm diameter propellers but high speed propellers of 240 mm diameter are also available..
The connection cable is made of a flexible “Titanex” sheathed cable containing 3 wires with a section of 2.5mm². This cable is covered with a dyneema braid ensuring the recovery of the drag forces of the hydro-generator. Thus the electrical cable is not subject to any mechanical stress. A stainless steel carabiner allows you to attach the system to an existing attachment point on your boat. We recommend positioning this attachment point at a maximum height of 60 centimeters above the waterline level to ensure optimal operation.
The length of the cable between the carabiner and the hydrogenerator is approximately 320 centimeters. The length of the electrical cable between the carabiner and the electrical connector can be adapted to your needs.
We provide a bulkhead connector to attach to the rear of your boat. However, if you do not wish to carry out drilling, you have the option of routing the cable on the deck of the boat and up to your electrical installation.
The electrical installation is reduced to a minimum. A small electrical box (160x80x56mm) must be installed as close as possible to your battery park, ideally at a distance of 1 meter. A resettable circuit breaker (supplied with the hydrogenerator) ensures electrical protection of the assembly. A base connects the hydrogenerator to the electrical box. A side USB connector (waterproof) allows you to connect the box to a computer to carry out maintenance and configuration update operations. All these operations can be done on your mobile phone via Bluetooth connection.
A phone application allows you to control and monitor the operation of your hydro-generator. It connects via Bluetooth by pairing like any Bluetooth device. You can start or stop the propellers to allow you to reassemble the system after use. You can also observe parameters of interest in real time such as rotation speed or production. The application also allows you to configure your hydro-generator to define the characteristics of your battery. Finally, you can update the hydrogenerator’s onboard software directly with the application. If you don’t want to use your phone every day, the hydrogenerator is designed to work autonomously. An ignition button on the front of the electrical box allows you to turn it on and it will do the rest. And if you forget to turn it off, don’t panic, the system has an automatic shutdown if it detects no activity.
Why is the production limit different if I have a 12 Volt or 24 Volt battery?
The rotation speed of the Seawing propellers is controlled by the electronic box. The maximum speed that the propellers can reach depends on the battery voltage. The higher the battery voltage, the greater the possible propeller speed. As the extractable power of the generators depends on the rotation speed of the latter, the greater the battery voltage, the faster the generators can rotate and therefore produce more.
Will my boat lose speed while the system is operating? How much ?
Yes, your boat will be slowed down by Seawing. This is normal, we recover the wind energy in the sails to turn the Seawing propellers. It is difficult to give precise figures because braking depends on the size of the boat and the sail as well as the wind conditions. Generally speaking, Seawing slows you down by 0.1 to 0.3 knots.
Seawing has two propellers, on other systems there is only one. For what ?
Seawing is a towed hydro generator. Like your boat, it must ensure its stability in the water. A propeller creates a restoring torque that is difficult to recover given the size of Seawing. To achieve this, we mounted 2 counter-rotating propellers whose return torques cancel each other out.
Does your system slow down the boat more than 1 propeller systems?
In theory yes. But since we can control the speed of the propellers, we impose a speed on them to minimize drag without penalizing the power produced. So Seawing's performance is always optimal.
How do we choose the size of the propellers?
This choice depends on the speed of your boat as well as your energy needs. If your boat goes fast (beyond 9 knots) or you have small energy needs, we will prefer 240mm propellers. Otherwise, we will choose 280mm propellers.
How to attach Seawing to the boat ?
Our hydrogenerator is towed. It must be attached using its carabiner to an attachment point on the transom of the boat. This attachment point must be at a maximum height of 60 cm above the waterline and the more centered it is, the better. It must be able to withstand a force of 150 kg. However, you can install our optional mounting plate if you do not have a suitable attachment point.
What batteries are supported ?
Our converter supports Lithium-Ion, Lithium-Iron-Phosphate and Lead-Acid batteries, regardless of battery capacity. Battery voltages should be between 12V and 48V.
How to maintain the hydro-generator ?
We recommend removing the hydro-generator from the water when it is not in operation. Before storing the hydro-generator, check that the propellers rotate freely and rinse the system with fresh water. Check the condition of the electrical connections from time to time. Contact us if necessary for more detailed maintenance.
What happens when the batteries are charged ?
When the batteries are charged, the Seawing's propellers are automatically blocked to stop electrical production. You can then bring the system back on board.