i've attached a photo of a mobile sonar unit i've built. the model is a humminbird max10 - costs around $100. it came from the US and unfortunately depth and temperature measurements are in imperial only. apart from that minor inconvenience it's great!
as you can see i built a little floating platform for it. the prototype is a little rough and i may make a better final version. basically it's just 2 pieces of wood sandwiching some polystyrene ceiling tiles... all bolted together.
i tested it today and it worked perfectly. the spot where i normally dive is about 93m according to this. it's so sensitive that it even registered the weights at the bottom of the rope, which happened to be at 60m today. i then slowed down the scrolling speed and did a quick dive. when i surfaced i could see a fine well defined line tracing a V-shaped profile (of depth versus time).
the unit needs a 12v power source. for this i bought a battery holder for 8xAA batteries. these are stored inside a watertight box (designed for electrical systems). the box was screwed down to the wood. excess cables were coiled up inside the platform to keep things neat.
i have no doubt that this will be a really handy piece of kit for improving safety. it will take a little time to learn to interpret the signals, but already i am beginning to learn. for example, today i often saw a series of lines on the display near steep gradients. (in Dorothea - a slate quarry). these signals are produced by series of slate 'terraces'.
if you've ever thought about using a fish finder in this way then i would recommend the piranha max 10.
ps: it can measure depth to 180m and the scale is variable. when diving deep we will be using the 360ft range, so i've stuck on our own scale in metres for an easy way to measure depth.
as you can see i built a little floating platform for it. the prototype is a little rough and i may make a better final version. basically it's just 2 pieces of wood sandwiching some polystyrene ceiling tiles... all bolted together.
i tested it today and it worked perfectly. the spot where i normally dive is about 93m according to this. it's so sensitive that it even registered the weights at the bottom of the rope, which happened to be at 60m today. i then slowed down the scrolling speed and did a quick dive. when i surfaced i could see a fine well defined line tracing a V-shaped profile (of depth versus time).
the unit needs a 12v power source. for this i bought a battery holder for 8xAA batteries. these are stored inside a watertight box (designed for electrical systems). the box was screwed down to the wood. excess cables were coiled up inside the platform to keep things neat.
i have no doubt that this will be a really handy piece of kit for improving safety. it will take a little time to learn to interpret the signals, but already i am beginning to learn. for example, today i often saw a series of lines on the display near steep gradients. (in Dorothea - a slate quarry). these signals are produced by series of slate 'terraces'.
if you've ever thought about using a fish finder in this way then i would recommend the piranha max 10.
ps: it can measure depth to 180m and the scale is variable. when diving deep we will be using the 360ft range, so i've stuck on our own scale in metres for an easy way to measure depth.
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