F-POD, LF-POD, Deep F-POD
The different hardware versions of the F-POD all have the same hydrophone and the same main circuit board and pre-amplifier board.
The significant differences are in size, running time, and battery types.
All F-PODs and C-PODs with their hydrophones are individually standardised producing a detailed report including the radial senstivity graph shown here.
The F-POD and LF-POD are buoyant to assist deployment and recoveries, and these can be fitted with the integral Acoustic Release.
Standard F-POD
For longer deployments
The standard F-POD takes 10 D-cells and runs for 4+months on alkaline cells or 8 months on primary lithium cells.
The Lithium Rechargeable F-POD takes 25 21700 lithium cells, runs for 7 months, and is the longer housing shown.
Polypropylene housing. Depth: 100m (or more for older PODs!)
Rechargeable Lithium F-POD
This version is slightly longer than the standard version and takes this battery pack holding 25 rechargeable lithium 21700 cells.
With 5Ah cells the running time, logging alternate minutes, is 14 months, allowing year long deployments.
To meet vessel safety standards lithium packs should not be changed at sea. They are in 5 stacks that have built-in short-circuit protection, and diode protection against cells being inserted the wrong way round.
Cells must be bought locally.
Little F-POD
Easier for deployments by fishers on nets
6 weeks continuous running time
4 alkaline D-cell battery pack, runs for 8wks. This will be replaced soon by a lithium rechargeable version in a slightly longer housing and will run for 3 months.
Polypropylene housing.
Depth: 150m
Deep F-POD
For depths to 2000m
Heavy aluminium housing, as shown. This is supplied with a thick silicone sheath to prevent any metal:metal contacts when deployed.
Battery options are D-cells, which can be alkaline or primary lithium cells. On alkalines the running time is 4-5 months, or 8 months on primary lithiums, and can be nearly doubled by logging alternate minutes - as with all current F-POD versions.
F-POD Acoustic Release
This integral acoustic release will be available in 2025. It will fit as an alternative to the normal lid on enabled standard F-PODs.
Each POD has its own acoustic release code that is sent by a deck unit and actuates the release which has a 160kg breaking strain line for retrieval of the anchor.
A default release date can be set in the POD before deployment, so the POD would release and remain tethered by the retrieval line. This option can be used without a deck unit.
If the batteries are failing release is forced so that it does not become inaccessible.
Veteran C-POD
This old C-POD is still working normally with a very good calibration result after 15 years of use.
C-PODs are no longer manufactured, but are still in use and there is a supply of replacements as they are released from projects converting to F-PODs.