On the Development of a Mid-Depth Lagrangian Float for Littoral Deployment

Yuri Katz, Morel Groper

Research output: Contribution to journalArticlepeer-review


This study presents the complete, detailed development process of an enhanced one-man portable Lagrangian float designed for littoral deployment to depths of up to 300 m. The design focused on maximization of the Lagrangian characteristics of the hull, minimization of the noise emission and energy efficiency of the propulsion system, and the versatility of the platform for various scientific missions. The platform is propelled by a variable buoyancy engine that is actuated by an oil-submerged, gas-pressure assisted micro gear pump. The pressure assistance lowers the pressure differential across the pump ports at depth, resulting in quieter and more efficient operation. An enhanced proportional–integral–differential control scheme is employed to pilot the platform. To enhance diving safety, a software safety agent was incorporated. If the software safety agent detects a major failure, a drop weight is released. To eliminate the chance of water ingress through dynamic hull penetration, the drop weight is actuated by an in-house developed magnetic coupling mechanism. An onboard installed hydrophone continuously records and monitors ambient sounds for phenomena of interest and enables commands and mission updates from the surface. For surface recovery, the platform is equipped with GPS and an Iridium beacon for long-range localization, and an RF beacon and strobe for short-range localization and as a backup. The performance of the platform is demonstrated in a simulation and in an actual real sea mission conducted in the eastern Mediterranean at a depth of 10 and 12 m.

Original languageEnglish
Article number2030
JournalJournal of Marine Science and Engineering
Issue number12
StatePublished - Dec 2022

Bibliographical note

Funding Information:
This work was supported in part by the Israel Ministry of Science and Technology (MOST) action for Agriculture, Environment, and Water for year 2019 (Grant No. 3-16728).

Publisher Copyright:
© 2022 by the authors.


  • Lagrangian float
  • underwater pressure hull
  • variable buoyancy engine

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Water Science and Technology
  • Ocean Engineering


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