Frequently Asked Questions


If you have a specific question not covered here, fill out an enquiry form and we’ll get back to you with an answer within two business days.

How is the Fiobuoy different from other acoustic release systems?

The Fiobuoy is different from traditional acoustic releases because it combines a release, surface marker, retrieval line and storage, all in one product. Read an in depth analysis of the major differences on our Fiobuoy v Acoustic Release page.

Is the Fiobuoy protected against rope entanglement?

The Fiobuoy is designed specifically to combat rope entanglement. Its design replicates the method rope manufacturers use to supply rope; the simplest and most effective way – on a spool. Rope released from a canister can get easily tangled, whereas the Fiobuoy unwinds naturally, and our Winders make for simple and fast re-deployment.

Am I limited in the type and length of rope I can use?

The design of the Fiobuoy makes it easy to customise the rope for your specific deployment needs. Our TD100 & AC100 models, which are rated to 100 metres, can accommodate a maximum of 120m of rope. While our TD200 & AC200 models can fit a maximum of 250m all using 10mm diameter rope. Of course if you use a thinner rope you will fit more on. Because each Fiobuoy is made to order you can choose the length and strength of rope you need. We supply two types: 10mm Aquatec with a breaking strain of 1,300kg and 10mm Dyneema with a breaking strain of 5,000kg. Provided it is neutrally buoyant, our customers can also supply their own rope.

How can I be sure the Fiobuoy will surface in high currents?

In the ocean all bodies are affected by high currents but the unique dynamics and design of the Fiobuoy means it works differently to normal floats and acoustic releases.

Provided your Fiobuoy has an excess of rope for your deployment depth, your Fiobuoy will surface. Once surfaced, for the period of time it takes for the remaining line to unwind from the spool, you have time to retrieve it. This is because during this time the Fiobuoy is effectively an untethered free-floating body which will not be dragged under by currents (unless they are extremely strong).

Also the Fiobuoy’s unique ‘unwinding’ principle means it doesn’t need to drag or pull the full length of line through the water column. This combined with the fact that at the time of ‘unwinding’ the Fiobuoy doesn’t lift anything but its own weight means it rises to the surface easily. Click here to see this unique unwinding principle in the Fiobuoy in Operation movie.

Some acoustic releases don’t work in fresh water. Is the Fiobuoy suitable for both salt and fresh water deployments?

The design and dynamics of the Fiobuoy make it suitable for both salt and fresh water deployments i.e. oceans, rivers and lakes etc.

Is the Fiobuoy difficult to maintain and service?

The Fiobuoy requires only minimal and simple maintenance, which can be carried out by the user. Depending on its use, the Fiobuoys Battery Pack need only be changed every 3-6 months for the acoustic models, and 12 months for the Time/Date. Currently the battery packs use high quality alkaline cells with standard battery pack construction. Fiomarine can supply packs, or provide technical details for local construction by qualified agents.

At the time of battery replacement the Fiobuoy’s o-rings can also be replaced, and your Fiobuoy is ready for deployment again. A Maintenance Kit includes everything you need. O-ring replacement is typically recommended every 12-24 months depending on inspection.

How do you protect against fouling on the Fiobuoy’s release?

The Fiobuoy’s patented release mechanism is designed in a way to ensure fouling does not affect its release. Many acoustic releases are designed with a mechanical arm, so when they are opened debris and seaweed etc can get caught on the arm preventing the line to be released. The Fiobuoy was designed with a jaw and ball-pin, not an arm. This means that when the release is actuated the jaw opens, releasing the pin and pushing any growth away.

However, if you are deploying in areas where high amounts of growth is expected, for instance in shallow or warm waters, you may need to consider marine growth on the rope spool. To prevent this Fiomarine recommends, and can supply, an application of an antifouling agent on the outer layer of rope.

What is the Fiobuoy’s lifespan?

Fiobuoys are built to last a minimum of 10-15 years. Our very first models ever made are still in perfect working condition and still being used by the Royal Australian Navy.

Can I use other battery types?

Currently we use alkaline batteries which have a life of approximately 3-6 months or 12 months, depending on your Fiobuoy model and usage patterns. We prefer to use alkaline batteries because they are compatible with the Fiobuoy’s specific electrical requirements. We are however constantly reviewing other battery chemistries and expect to be able to use some of the newer lithium technologies soon.

Our 200m models do have spare internal space to support two battery packs providing extra energy for longer deployments.

Will the Fiobuoy still work in extreme temperatures?

The Fiobuoy’s mechanics, plastics and electronic systems will not be affected by extreme temperatures. We have customers successfully deploying Fiobuoys in areas ranging from near freezing in the Arctic Ocean off Canada to 26°C in the Pacific Ocean off Papua New Guinea.

Will the Fiobuoy’s acoustics interfere with my other equipment?

The Fiobuoy’s acoustic system transmits less than 1 watt into the water. It is highly sophisticated and due to its Spread Spectrum technique is almost undetectable by other systems. As a result equipment such as ADCPs will not be affected, nor will such systems affect the Fiobuoy’s communications.

Is your Deck Control Unit compatible with other releases?

No it isn’t. After researching this option we found that many multi-brand compatible systems try to do too many things and ultimately end up not doing any of them particularly well. We have concentrated on making our system the most reliable on the market. To ensure this, we use highly sophisticated encoding and Broad Band Spread Spectrum technology, making our Deck Control Units integral and specific to the functioning of Fiobuoys only.

What frequency does the acoustic signal transmit on?

Unlike traditional acoustic communications equipment, the Fiobuoy’s system uses advanced digital signal processing employing Broad Band Spread Spectrum techniques (similar to mobile phones). This means the transmitted energy is ‘spread’ over a range of frequencies, typically 14 kHz – 31 kHz for the Fiobuoy. This has the advantage of overcoming real world impediments such as Doppler shift and signal bounce due to temperature or salinity layering or marine life.

The system is not the traditional simple signalling system but full two-way confirmed-packet protocol enabling modem to modem type data communication.

Can I use one Deck Control Unit to activate more than one Fiobuoy?

Yes, each Fiobuoy has a 6 digit security access code, and with the acoustic models this also acts as your communications address. Our standard Deck Control Unit can be set to access any single Fiobuoy in your fleet. There is no global broadcast function.

What is the range of the acoustic system?

We have limited the Fiobuoy’s acoustic range to a distance of 500m line-of-sight. This is primarily because at no stage is the Fiobuoy untethered from its anchor, so it will always be at the original drop site. With GPS devices, users can usually be certain of being within a few tens of metres, well within the 500m range. We can also supply systems of 1km distance or greater on request.

Is the Fiobuoy’s jaw and pin strong enough?

In traditional acoustic releases, the release mechanism needs to support the payload weight. Whereas, with the Fiobuoy, the rope (with a breaking strain of 5,000kg) not the jaw and pin, holds this weight. The Fiobuoy’s jaw and pin only needs to hold a maximum of 8kg of buoyancy plus some tidal drag. The jaw and pin has also been tested to withhold several times this load.

If there is a reduction in buoyancy whilst the Fiobuoy is submerged, could the rope slip?

Whilst the Fiobuoy is submerged, the rope (held securely by the jaw and pin), sits between the Fiobuoy’s handles. In order for it to slip, there would need to be a significant and sustained force pushed downwards directly on the Fiobuoy. This force would need to counter the Fiobuoy’s own bouyancy of 3.5 or 8kg.

Although unlikely, if this were to occur, the worst case scenario would see the rope merely slip between the next handles, remaining tethered and the jaws securely closed.


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