Electrification of a classic steel sailing dinghy

Some maritime projects have a very special history. During the rebuilding of our own Iroquois catamaran in 2019, we got to know the Molenaar Jachtbouw in Woubrugge. The owner at the time had once personally built a classic steel sailing dinghy for his family. In 2021, this unique vessel was sold to Peter, a local GP. While he was getting to know the dinghy, we continued building our catamaran at the shipyard. After an unexpected accident during construction in which the owner of Robust-MT sustained a head injury, Peter was fortunately on the scene immediately to provide first aid, allowing construction to resume quickly.

The circle was complete when Peter approached us in October with a request to fully electrify his sailing dinghy. There was great amusement and surprise when, upon our first meeting, it turned out that the former 'savior' and the catamaran builder had found each other again through this project.

Customer wishes

The original inboard petrol engine was noisy, maintenance-intensive, and no longer suited the desire for quiet and comfortable sailing with a young family. The main criteria for the transition to electric boating were:

Reliable inboard electric motor

A compact and maintenance-free drive system with sufficient torque to safely maneuver the heavy steel chimney.

Solid energy storage

A battery pack with high energy density and sufficient capacity for longer day trips.

Modern onboard network

The installation of a clear control panel and a basic 12V network on board for lighting and peripherals, compatible with traditional tiller operation.

Professional shore power

A certified and safe shore power connection to charge the boat at your own jetty or in the harbor.

The solution and efficient assembly

To optimize costs for the client and increase involvement with their own vessel, a unique form of collaboration was chosen. In the months leading up to the installation, Peter personally and expertly dismantled the old petrol engine. Additionally, he cleaned the engine compartment, prepared the foundation, constructed a sturdy platform for the battery bank, and personally installed and precisely aligned the new electric motor.

Subsequently, our engineering team from Monster took care of the complete technical and electrical finishing. Within one intensive working day, the entire installation was assembled and connected by two specialists:

Drive & Energy

A powerful WaterWorld Electronics 4 kW inboard electric motor (48V) was chosen , coupled with a robust and durable 133Ah lithium battery bank .

Propeller Shaft & Propulsion

To make optimal use of the efficiency of the new electric motor and to perfect the streamlining, the system is equipped with a specially calculated new propeller.

Electrical Engineering & Operation

A complete, high-quality Ratio shore power set has been installed, including a corresponding battery charger and distribution materials. Because the boat is steered with a classic tiller, the new switch panel and digital display are mounted flush in the cabin, close to the cockpit. As a result, all data and controls are directly within reach of the skipper.

Peter

Global cost indication

For a custom project of this kind, a transparent calculation is essential. Thanks to the client's active self-help, significant savings were made on the total installation hours. Below you will find the exact cost overview of this electrical installation: We would be happy to advise you on the total investment for such a project. Attached you will find a transparent overview of the actual costs for this specific electrification:

Post	Description	Amount (incl. VAT)
Total investment	Fully ready to sail and delivered 100% electric	€ 15,279,-
Drives & Electrics	WaterWorld Electronics 4 kW motor, including shore power supply, distribution materials, display, and the new switch panel.	€ 5.961,-
Energy storage	133Ah battery bank and all associated connection accessories.	€ 3.599,-
Charging technology	Professional, efficient battery charger tailored to the lithium battery bank.	€ 704,-
Propulsion	New propeller, specifically calculated for the speed and torque of the electric motor.	€ 595,-
Working hours	Man-hours for extensive prior technical coordination, system engineering, and one full day of on-site installation work by two specialists.	€ 4.295,-
Small material	Necessary installation materials, heat shrink tubing, and fastening materials.	€ 125,-

Result

The transformation of the classic steel sailing scow is an unqualified success. Peter and his family have already been enjoying their silent sailboat for two full sailing seasons. The WaterWorld engine offers instantly available torque, making maneuvering and mooring the scow significantly easier and safer. Thanks to the thorough preparation by the client and the sleek, one-day cabling installation by Robust-MT , a technically perfect result has been achieved that will last for generations.