Acoustic receiver arrays must be deployed in locations where conditions on the surface, through the water column and on the ocean floor maximize the detection capability of the acoustic receivers – sound travels very well in water, but ambient noise, certain oceanographic conditions, and reflective surfaces near a receiver can interfere with transmission. Commercial fishing activity in the planned deployment area can also result in equipment losses because of gear entanglement. Though Kintama uses, and can provide you with trawler-resistant mooring equipment that will greatly reduce the odds of equipment damage or loss as a result of fouling from fishing gear, it is prudent to reduce that risk through an optimal choice of array location.
Kintama has extensive experience deploying arrays of VEMCO’s VR2, VR3 and VR4 receivers in a variety of conditions and locations, and have developed specific positioning systems to protect your receiver investments.
VR2s are best suited for short term or shallow water deployments where they can be readily accessed from an above water mooring, or by divers. They are rated to 500m, powered by a single D-cell battery that provides approximately 1 year of power, and in most cases data can only be uploaded from them directly once recovered to the surface. Although VR2s are less expensive receivers managing large arrays of them means that periodic data recovery grows to dominate overall projects costs.
VR3s and VR4s are designed for longer term deployments, and are powered by lithium batteries that last between 5 and 8 years. These receivers feature an integrated acoustic modem that allows the user to upload detection data wirelessly from the surface using a topside computer and hydrophone. What sets a VR4 apart from its VR3 predecessor is its ability to detect both at the standard 69kHz VEMCO tags, and the newer much smaller 180kHz tags. Additional sensors detecting surrounding oceanographic conditions also can be accommodated with a VR4 using a standard-sized port.
With over a decade of deployment experience of all types of receiver arrays in a variety of coastal ocean and river conditions, we have developed optimal strategies to deploy receivers that minimize risk and maximize success and ultimately data yields. Learn more about the deployment services we provide, as well as the positioning systems that you can buy to protect your deployed acoustic receivers.