Lake Tahoe

Since I was a child, Lake Tahoe has been my favorite place on Earth! I now live thousands of miles away from it, but I still take every opportunity dive in it whenever I visit my parents in Reno. It is Lake Tahoe, in fact that inspired me to learn to scuba dive at the age of 12 years old.

Over the holidays we had planned to do two deep(ish) dives off of Hurricane Bay, but we were snowed out the first day, and blown out the second. I could have made it in pretty easily with my slim rebreather, but many of the team members were using doubles and slinging 80’s, which would have been tough in the 4-foot waves, so we decided to have breakfast instead. The upside to the trip up there was that I got this nice panorama of the lake!

Lake Tahoe, as lakes go, is very interesting. It is the second deepest lake in the United States and the tenth deepest in all the world. The Lake is amazingly clear with a water clarity of about 100 ft. This is partially due to the fact that about 40 percent of the precipitation that falls into the Lake Tahoe Basin lands directly on the lake and because the remaining water drains through granitic soils, which are relatively sterile and create a good filtering system.

It was created about 2 to 3 million years ago by a geologic block fault, which is a fracture in the Earth’s crust causing blocks of land to move up or down. The Lake Tahoe we know today was shaped and landscaped by the scouring glaciers during the last Ice Age.

As a dive site, it is nothing short of perfect! The altitude makes planning technical dives a little tricky, but the amazing water clarity and interesting boulder features make it well worth the extra trouble. I’ve been down below 300 feet on Rubican Wall, and I have to say that it is still one of my most memorable dives.

  • Lake Tahoe Facts:
  • Maximum depth (second deepest in the U.S.): 501 m 1,645 ft
  • Average depth: 305 m 1,000 ft
  • Maximum diameter (north-south): 35 km 22 mi
  • Minimum diameter (east-west): 19 km 12 mi
  • Surface area: 495 km2 191 mi2
  • Average surface elevation (above sea level): 1,897 m 6,225 ft
  • Highest peak (Freel Peak): 3,320 m 10,891 ft

Info from: USGS.com

More Fun With DIY ROVs

Ever since I discovered the article about the $99 home made ROV, I’ve been all excited about building my own and using it to attach decent lines onto wrecks that are below 300 feet. In other words, wrecks that are deep enough to dive on technical scuba, but too deep to spend bottom time searching for. Since the $99 ROV does not have thrusters, I set out about finding a way to build some when I discovered Doug Jackson’s article about his adventures building this ROV named BOB. I have say, I really like his design! Not only does it use reasonably priced parts, but he’s been very clever in how he has used modified vintage Atari video game controllers and relays to drive the thing.

Here is a quick overview of what he has used:

  • Five, 500 gpm Johnson Bilge Pumps as thrusters. He got them for $10 each, but they now cost about $20 when you buy them from Boater’s World.
  • Atari vintage joysticks from eBay
  • PVC pipe, epoxy, wire ties, and Cat 5 cable from the local hardware store.
  • A 9V battery to power the relays
  • A 12V battery to power the pumps
  • An Atlantisâ„¢ Guide View Underwater Camera System
  • A television to serve as the monitor

Doug provides very detailed directions on how by constructed BOB, and even talks about how a person might modify the pumps to be fitted with propellers, thereby making the ROV more effective in areas of heavier current.

In BOB’s lake trial, it was tested to 60 feet and performed well. A neutrally buoyant tether cable was obtained by attaching 1 foot sections of foam pipe insulation every 6 to eight feet. Telling how close the ROV was to objects was apparently difficult, and Doug mentions that it either needs better lighting or lasers that cross 6 feet in front of the device might be of help.

Here are some direct links to areas of interest on Doug’s site:

Again, I really like Doug’s design. I think the most challenging improvements would be to increase the thrust by using propellers and to prevent the pumps from flooding under greater pressure. I’m also not sure about how one could manage the voltage drop over a longer tether cable. I don’t believe the design, as it is, can make it 400 feet down to the S.S. Tahoe, but I do see it making the dive with some HID light, tighter seals, and a little more thrust.

99 Dollar ROV

It’s not remotely operated, so you can’t really call it an ROV, but the guys over at engadget.com and divester have posted stories about this nifty little 99$ creation last week, and I think it’s pretty cool. Apparently it was made for under $100 in just two weeks. It has two cameras, an IR illuminator, some cleverly bent PVC pipe, one heck-of-a-lot of zip ties, a glow stick, and a 100 foot tether by which it receives power, and sends a video feed to the surface. I especially like the clamps that hold the camera housing together.

They didn’t mention the depth rating, but assuming that the tether could be extended, and the housing could take the pressure in deeper waters, this might really be a great technical diving tool for finding wrecks, and attaching decent lines to them. Of course the lack of thrusters would be problematic for working in waters with current, but I can think of one primed-to-dive wreck in Lake Tahoe that sits in 400 feet of water with no line on it that this baby might just be able to lend a hand with. Can you say S.S. Tahoe?

I’m actually thinking about making one of these for myself. If I do, here is a list of things that I would add to it:

  • Two Sartek HID Underwater video lights
  • An arm for attaching lines to underwater wrecks
  • A longer tether (400 Feet)
  • A stronger lexan housing if needed

I guess I’m pushing the price point up a little over the $99 mark, but what why not? I can use the lights on my video camera (when I get one), and I might just hook onto a nice shipwreck.