Case Study: Seahorse Amphibious Vehicles & Duck Tours Ltd
Shaft Power Measurement Supports Amphibious Fleet Electrification
The Client: Seahorse Amphibious Vehicles
Seahorse Amphibious Vehicles was founded by marine engineer Graham Lumley in 2014 to address safety and efficiency challenges affecting the Amphibious Passenger Vehicle (APV) sector, which had long been reliant on Second World War–era vehicles (DUKWs) and heavily adapted donor vehicle chassis. Seahorse set out to revolutionise the industry with innovative new purpose-led designs.
In 2022, the company entered full production at a new UK‑based factory, marking a significant milestone in its development. The launch of the Seahorse MKIII in the same year reinforced a focus on safety, durability, and a future‑ready platform designed to support electrification.
Through its sister companies, Windsor Duck Tours and Splash Tours Liverpool, Seahorse operates established amphibious tour services, while also supplying vehicles to a growing international customer base.
The Challenge
Seahorse sought to enhance their APV’s performance by accurately measuring power usage during water operations.
The primary objective was to gather precise power consumption data at varying speeds, which would be used to optimise the design of an electric drive system and appropriately size the battery pack.
The challenge was to determine the kilowatts per hour consumed by their existing diesel‑hydraulic vehicle, where power demand can vary significantly depending on operating conditions and load.
The Solution
To support this work, Seahorse were supplied with a Datum Electronics Shaft Power Measurement Kit, a portable test system designed to measure shaft torque and rotational speed directly on the driveline, allowing true shaft power to be calculated under real operating conditions.
This state-of-the-art equipment was used to accurately measure the rotary shaft speed of a 76 mm diameter shaft, with data transmitted wirelessly from the rotating shaft for logging and analysis during testing.
By integrating this advanced measurement technology, the Seahorse team were able to gather the critical data required for assessing and improving the energy efficiency of their vehicles.
The Outcome
The data collected using the Shaft Power Measurement Kit revealed that the water jet system, previously estimated to consume 40 kW/h, was actually operating at a significantly lower 25 kW/h.
This unexpected efficiency was instrumental in guiding the development of a new electric drive system, enabling Seahorse to design a more optimised and effective battery pack for their existing fleet.
In October of 2025, Seahorse unveiled the world’s first all-electric APV, the Seahorse MKV, capable of accommodating up to 36 passengers and two crew members while running for a full day on a single charge.
These impressive new vehicles, themselves a testament to what can be achieved with years of R&D by skilled engineers in purpose-built facilities with specialist equipment, are anticipated to be coming to the Thames river in London in the near future.
To learn more about Seahorse Amphibious Vehicles – visit seahorseamphibious.com.
Jon Nicholson
Sales Engineer
“Projects like this show the value of measuring power directly in real operating conditions. It was good to work with the Seahorse team and support their efforts to better understand drivetrain performance as they move towards electrification.”
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Datum SPMK
Shaft Power Measurement Kit
The Datum Electronics Shaft Power Measurement Kit enables accurate on-site collection of torque, power, and RPM data. Designed for ease of use, the kit can be applied in six simple steps, delivering precise data within an hour.
Ideal for single-day trials, the kit helps assess power levels and torque characteristics such as startup and maximum torque. It features strain gauges with encapsulated coatings for simplified environmental sealing and provides outputs for shaft torque, RPM, and power with an electronics accuracy of 0.1%.
The system includes user-friendly PC software for data display and logging, with optional interfaces for logging and control systems. Suitable for shafts starting from 30mm in diameter, the kit is designed for marine, vehicle, and other rotating shaft applications, offering a practical solution for measuring torque and power in real-time.
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