M/Y Jester: A New Hybrid Heart for a Hardy Explorer

Following her original refit at Pendennis in 2021–23, 69m expedition yacht M/Y Jester returned to Falmouth in September 2025 for another ambitious project: replacing her original engine with a completely new hybrid propulsion system.

A year of detailed preparation preceded her arrival, with Pendennis' engineering and naval architecture teams undertaking extensive 3D modelling, systems design and structural planning. This was essential to integrate the new hybrid machinery within the existing vessel, including significant changes to the engine room, exhaust arrangements and surrounding structure.

The engineering programme involved removing the original Deutz engine and gearbox and installing a new main engine, gearbox, electric motor, two generators and a substantial battery bank. The installation presented considerable logistical challenges, including removing the original funnel and creating an access route through the bridge and upper decks to extract the existing machinery. A replacement funnel was subsequently fabricated in-house at Pendennis.

The resulting hybrid system allows Jester to cruise on electric power alone at speeds of up to 8 knots, with a combined boost mode reaching 15 knots, while reducing NOx emissions by approximately 83%.

Bringing together Pendennis' engineering, fabrication, electrical and naval architecture expertise, the project marks another significant milestone in the ongoing relationship with Jester and her Owner's team.

Read more about Jester here or by reading her article in Issue 22 of Pendennis’ in-house magazine, Voyage.