Sorry, this is not strictly fishing related, but I think you guys would be most able to help.
We have a small sail boat (26 ft), that we want to use for acoustic monitoring of sea mammals. We have a small receiving hydrophone (about 1 cm diameter, and 2 cm long, weighing about 200 g) connected to a cable, 3 mm diameter, and 9 meters at the moment. We want to tow this hydrophone behind the sailboat. Currently, there is a small weight connected close to the end, but the problem is that when we sail (max 6 knots), the hydrophone is close to the surface of the water. I would like the hydrophone to "dive" to a depth of at least 5 - 10 meters, or even deeper. (I know I will have to extend the cable in order to do that.)
Are there any diving lures or "trolling planers" locally available that can do the job? I have read that "dipsy divers" can do the job. Are these locally available?
Any help or suggestions will be greatly appreciated,