Say Nuth Khaw Yum (Indian Arm), BCOctober 12 2014
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Goals this expedition:
Reach 200+ meters depth. CHECK
Max Depth was 208.91 meters. Approximately...
Test New Tether, inside 1/4 inch polypropylene rope. CHECK
So far So good. It seemed to do well, but we also had better tether management than in the past. We used the lifesaver candy method to attach a clump weight for the descent. It helps get you down faster, using much less battery power and, crucially, keep tension on the tether. With tension on the line, you are not guessing how much tether to play out, because you can feel if it needs more. It also lets you lift the rov off the bottom without using motors (kicking up sediment). Though obviously I forgot to do that most of the time...
Test the IMU Depth Sensor below recommended depth of 100-140m. CHECK
We descended well beyond that and it kept on working. Hooray!
Test 'Boat Console" CHECK
I mounted a small wood console (I made it!) consisting of the tether spool on a slip-ring spindle as the base, then a small box above it to hold electronics and a small table like top to place the laptop for better viewing. It was a huge improvement having a space to work from instead of my lap/on the boats tube. It will also speed up expeditions since many things can stay in place ready to use next time.
Test the boat tent. See picture. CHECK
We could see the screen better, we were warmer and drier, we looked kinda dumb.
In each of my previous expeditions, I have had water in 1 of the 4 battery tubes. Each time, this resulted in one battery (the one at the front) being ruined. I was extra careful this time. I used hair elastics (no ouch) under the o-rings to tighten up the seal. After 2 hours at or close to 200m depth, 3 of the tubes had a little water in them. But, none had enough water to submerge the batteries past their plastic sleeve. I am pretty happy with this since this was the deepest by far and also the longest I have run the ROV. The leak must be incredibly slow to allow such a small amount of water in.
Also the batteries in tube 'D' don't discharge. I have previously tested the tube and the fuse, and they both seem like they should work. odd. Three battery tubes have been plenty on each expedition, so I have not put much effort into the problem.
Controlling the ROV.
It can be difficult to control the ROV with a long tether. Particularly when you are running from the shallows area to deep water a ways off as there is a lot of horizontal area between you and the ROV for the tether to dragged across and/or tangled in. This time around, because I kept good tension on the line, it didn't give any slack for manoeuvring. I was mostly focused on travelling to deeper water, but when I occasionally wanted to stop and check something out, I forgot to give some slack and was unable to turn. Early on, I used the tension on the tether to lift the ROV without the props which kept the water from filling with sediment clouds. But later on I forgot. So next time will need to remember both to use the tension to lift the ROV when I can and to give some slack to manoeuvre. Perhaps I will get that as a Tatoo!
If you have any comments or suggestions type them in the box below. :D
I got water in a different battery tube this time. I'm not supprised the one that leaked last time was dry this time around. I used hair elastics ('no ouch' hair bands) under the o-ring to tighten things up. My battery tubes were particularly loose fitting compared to previous battery tubes. The hair elastics make the tube very tight. It is still easy enough to get off though thanks to my integrated BTcap handles. ;)
Here is the first video from the expedition. The link starts at 2m31s, just before you see the first fish. Hope it is as exciting for you as it was for me. :D
Below is a link to the second video, but first, a warning. It isn't much fun. There isn't a lot to see and it is mostly video of us having trouble with my computer and of the tether getting stuck. If you have an interest in that then go for it! :) It is also worth noting that we reached a depth 146m in the second video. At the time I thought we were in the middle of the water as there was nothing to see on the camera. The lights were on and the screen was blank. When the ROV finally returned to the surface, there was something yellow between the chassis and the ROV shell. I assumed at the time that it was just floating around. Later I realized that the camera was dark because either it wasn't sending a signal or the lights were not actually on. I suspect the lights were not on, since I can see some gradients in the video just above 40m, suggesting it was on at that time, but we should see 'snow' in the water, if nothing else. It is harder to see the screen when you are outdoors and a nearly blank screen can look blank. Which is what I assumed. At home, I pulled out the yellow object and it was brittle. It does make me wonder if there are glass sponges there as well (some of the sponges near passage island were a similar yellow color) , but I as I had hopes of find them there, I can't be trusted. ;) I will post a picture of it when I get home.
Here is the link to the second video.
youtu.be/nzcytdicO10?t=42m2s The link starts at 42m2s right at the deepest point of descent.
And below is the First video, aka, the one with fishes n stuff in it. :D
Preparation went smoothly, with one exception.
On the last expedition, the ROV had some tangled tether, which I cut. I re-soldered the quick connect onto my spare spool of tether (Just in case a few meters less tether became a problem). The spare tether needed to have a quick connect attached to the other end too (it is how I have it set up). I soldered the wrong end on. Then I didn't test it. Cause I was super 'certain' is was the correct one. boo! luckily it was the top side and I had some electrical tape. :)
This is a picture that basically looks like the connector I am using. I pour a tiny bit of mineral oil into it, to help fill any gaps water might seep into. During Depth test II, both the oil filled one and the dry one came back up without any sea water in them, and so far they have worked for me. I also use a zap strap across the connection, just in case the connectors became loose. They have so far been very tight.
A few weeks ago I scouted out a good spot, in 'Say Nuth Khaw Yum', BC, to reach deep water, from shore. The trick is that we still needed to be in a boat since the 'shore' was a cliff side. I bought a rock climbing anchor (though I am sure it has a different name) and headed out, on the good science yacht 'Bouncy Castle', with my good friend Cory Lake.