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Old 28-10-2013, 19:08   #1
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Camera on spreader for shallow water

Does anyone have experience with a camera on the spreader of a sailboat and the video displayed on the chart plotter or iPad?

This would be used instead of sending a crew member up the mast.
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Old 28-10-2013, 19:49   #2
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Re: Camera on spreader for shallow water

I would speculate that even a slight roll or pitch of the boat would swing the image around the screen of the iPad so much you couldn't get any really useful information. Of course you could install an image stabilized camera.
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Old 28-10-2013, 20:27   #3
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Re: Camera on spreader for shallow water

Glare on the water can prevent even a crew member from seeing depth accurately. A camera view isn't as good. Any person with polarized sunglasses can see better than a camera. An image stabilized camera only works to stop the motion of the mast and does nothing about seeing through the reflection on the water. They don't make one you can attach to a spreader and carry around all the time. A polarizing filter requires manual adjustment.

A GoPro camera works with an iPhone The Hero 3+ is nice but I would not attach one to a spreader and expect it to work well. They are waterproof but won't work remotely without a recharge. You could just rely on charted areas and not bother with areas where the depth is in question.

A camera is a 2D image not a 3D image. Computing depth from one image is impossible. From two images I have worked on a patent for computing such dimensions but it requires additional equipment worth more than the boat. A GPS, correcting base Station, a Ring laser gyro, and using a Kalman filter would work pretty and compute depth accurately well. Correcting the GPS with the base station would take longer than you would be willing to wait.

A pair of trained eyes (they see stereo in real time) would probably do the job and get you into a tight place in real time. A camera would get you grounded with a poor picture. Anyone too stressed to go up the mast would probably be worthless.
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Old 28-10-2013, 21:08   #4
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Re: Camera on spreader for shallow water

If the camera up at the spreader is not
the answer, how about a camera on a pole
held over the side? Like a poor man's sonar.

In another thread, there is just such a
video. I'll go try to find it. BRB (that's
be right back for you luddites)
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Old 28-10-2013, 21:13   #5
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Re: Camera on spreader for shallow water

Okay, I'm back. D'ja miss me?

It's post #34 on the Rudder nightmare at sea
thread. I don't know how to link to it.
(I'm pretty much a luddite)
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Old 28-10-2013, 21:16   #6
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Re: Camera on spreader for shallow water

I think it is a brilliant idea. I very much hope it works for you, and look forward to hearing back from you about the results. I wonder if you might be so kind as to record some of the video and post it on YouTube? I should like to evaluate it for myself.

Good luck, and I wish you success.
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Old 28-10-2013, 21:37   #7
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Re: Camera on spreader for shallow water

Go-Pro Hero 3 Black. On a stick clipped to a halyard haul it up, wide angle mode gives best results, wifi remote, monitor on iPad or PC.
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Old 28-10-2013, 22:15   #8
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Re: Camera on spreader for shallow water

since we are talking alternatives... hand held depthsounder and a dinghy or kayak. much safer than going up mast and even more accurate than a camera or spotter. you probably already have the dink and the hand held can be had for about the same as a gopro and would work as a backup should your onboard fail.
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Old 29-10-2013, 00:12   #9
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Re: Camera on spreader for shallow water

Let's see, $150 for steps to the spreader and a mostly reliable crew to climb up and watch for coral heads vice a video camera, transmitter, and receiving device in the cockpit and the endless hassles to get it to work and keep it working. Which would you chose????
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Old 29-10-2013, 04:16   #10
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Re: Camera on spreader for shallow water

Panbo review and discussion on related/similar matters here:
Panbo: The Marine Electronics Hub: FLIR M-Series nav cam test, Raymarine integration appreciated!
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Old 29-10-2013, 05:08   #11
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Estimating or judging the depth of water in front of the boat in tropical coral areas is all about colour perception and has nothing to do with 3D depth perception. Height definitely helps. Sometimes cabin height is enough, other times it the spreaders. Human eyes or cameras are fine as long as you can detect the colour.

Here is an extreme example at Beveridge where we played with the GoPro on a kite while we wandered about the atoll. You can clearly see a couple of deep bommies to the right.
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Old 29-10-2013, 07:19   #12
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Re: Camera on spreader for shallow water

I think a camera on the spreader is a great idea. In fact, when my mast was down last winter I installed wiring for one.

A FLIR would be great, but is huge $$$. I am planning to install a night vision security camera up there, with pan-tilt-zoom. I doubt that the night vision part will be as good as FLIR, but that's not really the main task. The main task is to have an instant lookout from a high vantage point, and also, to be able to have a video feed in the salon for better awareness of those below when underway. I think it might even be pleasant when anchored, to have a video feed from the spreader.

Mine will be design to allow me to tilt it down to use as a docking camera -- very useful in a case like mine, where you can't see the rail from the helm.

So the potential application of a spreader-mounted camera is much broader than just checking out a shallow pass in the Carib.
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Old 29-10-2013, 07:56   #13
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Re: Camera on spreader for shallow water

As Jimbo485 said, water color is the key to judging water depth in the tropics.

Here's a little ditty to help you remember...

Brown, brown, run aground,
White, white, you could be all right,
Blue, blue, sail on through.

Brown water is very shallow, so stay away--it could be grass or could be coral. White (or very pale blue) water could mean shallow water on the banks, so take caution. Blue water means deep water and safe passage.

Sun glare can be a problem, so it's best to navigate between 10 am and 3 pm, and try to keep the sun at your back. Small clouds drifting over the sun cast dark shadows that obscure colors. You'll need to be able to hold up and wait for the sun to come back out.
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Old 29-10-2013, 08:07   #14
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Re: Camera on spreader for shallow water

I like the kite idea more than attaching to the spreader. Send a WiFi camera up, get a live view, haul the kite down to recharge. Kite will give you more stability than the spreader, too. I have friends who put cameras on their board kites all the time, and you definitely get a solid view from aloft.
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Old 29-10-2013, 08:18   #15
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Re: Camera on spreader for shallow water

You don't have your own survellance drones?

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