Lagrangian Drifter

Status: Contents not yet checked by product owner

Description (extern)

The Lagrangian Drifters were designed and built at Helmholtz-Zentrum Hereon to follow the upper surface flow (approx. 50 cm). The main body of the Lagrangian Drifters consists of a 11 cm x 19 cm long tube with a flotation ring at the top. It is attached to a drogue of 35 cm in both length and diameter through a flexible cord within a distance of 10 cm to the tube. When deployed about 5 cm of the tube protrude from the water surface, resulting in a ratio of drag area inside to drag area outside the water of > 20. The tube contains a battery pack and an electronic board, which acquires and reports the collected data via a global satellite network in near real time. Two versions are available of which the simple version only reports date, time and position, at a predefined time interval (e.g. every 5 minutes), which enables to estimate surface current direction and speed. The version 2 measures in addition water temperature, air temperature and atmospheric pressure and can easily be equipped with additional sensors (e.g. salinity).

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  Langrangian drifter
• Langrangian drifter in the field
  Langrangian drifter in the field

Measurement Parameters (extern)

SENSOR PARAMETER	MANUFACTURER	MODEL	INTERFACE	UNIT	RANGE	ACCURACY	Registry UUID
DATE
TIME
LATITUDE
LONGITUDE
AIR TEMPERATURE	Bosh
WATER TEMPERATURE
ATMOSPERIC PRESSURE	Bosh

Technical Requirements for Operators (extern)

Where to install the instrument on the ship?

Lagrangian Drifters are dropped over board underway sailing.

What power supply does the instrument require?

The drifter is powered by 4 x 1.5V D-cell batteries. The power consumption for Version 1 is approx. 20 mW and for Version 2 approx. 30 mW.

What is the size of the instrument?

The size of the main body is 23 x 19 x 19 cm, the drifters underwater sail has a size of 35 x 35 x 35 cm and can be folded to a sheet 35 x 35 x 0.5 cm.

Water proofness

The drifter is water proof up to a water depth of approx. 1 m

What maintenance does the instrument require?

Lagrangian Drifters are typically not recovered. However in case they are recovered they should be cleaned, batteries need to be replaced and test of all sensors should be undertaken.

How will data be transferred?

Data will be automatically transferred via satellite on a predefined schedule e.g. every 5 minutes.

Prototypes

How many prototypes will be available for testing by operators by end of 2024? How many will be available by end of 2025?

	2024	2025
Version 1	30	tbd
Version 2	9	tbd

	Prototype #	Available for testing	Start date	End date	Maximal usage time
Version 1	1 - 30	Yes	Jun. 2024	Dec. 2024	150 days
Version 2	1 - 9	Yes	Jun. 2024	Dec. 2024	tbd

Costs

Cost of material for version 1 is approx. 300 Euro and for version 2 approx. 600 Euro

Technichal Details

Will follow soon!

Collaboration(s)

We started talking to two companies at the moment (Helzel Messtechnik and Sea & Sun)

Use Case(s) involvement

Solely Use Case 4 - Sailors

Development status

Technology Readiness Level

TRL 7

Commercial availability

Other Lagrangian drifters are available on the market, most of these are Version 1 type drifters and not environmentally friendly (one exception). Version two drifters are of very limited availability at significant costs.

Autonomous operation

Lagrangian Drifters are fully autonomous after deployment.

OSBK Interface

An OSBK interface has not been installed yet, as the boards are not available yet (27.08.2024).

Further details

Product Owners: Ruben Carrasco, Jochen Horstmann, Alejandro Ordóñez, Michael Streßer (HEREON)