Jim, I too am uncomfortable in 75 feet in Lake Travis. I don't think it makes me a poor instructor to be uncomfortable in low vis, cold water in the pecan grove as described. I've been there once, and didn't like it. I choose not to teach in places like that. It's why I don't dive in fresh water. It's why I don't teach in Texas.
Captain, You hit the nail on the head! Pecan grove. Yes campers there are entanglement hazards galore not far from our planned dive. And yes, entanglement hazards scare the sh*t out of me.
I have issues with dark, low viz, cold water..... I don't like it. I'm not scared of it, I just like to go slowly, have lots of backups and plan the heck out of it.
On our first dive my buddies light died. I gave her my primary and then discovered my backup was dead from having flooded. My backup lives in my BCD and probably got F'd up the weekend before during Rescue class. That's my fault for not checking the backup prior. Protocol says dive is over when you lose a primary. This instructor says, no, take my primary and go do your out and back depth nav exercise... so buddy and I did just that. We swam shoulder to shoulder with our compasses and lights. We swamp out about 15 kick cycles (which is far enough in low viz) and then swam back. Not the perscribed formation, but both of us were comfortable and we made it out and back with no hassle... other than gaining a few feet of height... but frankly the water was warmer there....
On the ascent the instructor insisted we hold a rope (for dive 1). I found myself overcrowded with 3 other divers on one stinking rope.... so I let go dropped down and grabbed the rope when the instructor motioned to. The instructor had explicitly said not to exceed his position when ascending. He was the "controlling" depth. As a rescue diver I felt comfortable being a few feet down the rope. As we were ascending one or more of the AOW students was struggling with the rope and pulling on it. This left me with alot of slack which became entangled in my right fin. I also found myself ascending chest up in a lean-back position. I decided that I'd had enough of the rope at this point and let go to untangle myself and then backed away and held position about 1 foot from the rope.
There are a couple of points here....
1) We'd already had issues on our first dive. The second dive shouldn't have happened without proper lights. It was out of protocol, but still inside my tolerance for safety so I was okay with it.
2) The instructor alleged to the Course Director that I was misbehaving on the first dive. I'm sorry but I don't think it's necessary for me to hold a half inch rope with 3 other people kicking me and jostling me. That makes me uncomfortable. I like my reg in my mouth and my mask on my face...... which is contraindicated to contact diving. Dropping down a few feet didn't materially affect my safety stop 15 vs 19 is really irrelevant. Entanglement is always a hazard when diving around ropes. Removing myself is a valid call. Provided that I could hold position it doesn't matter if I'm holding the rope.
3) Lastly, I've taken peak performance buoyancy. My buoyancy isn't perfect, but heck, neither are most divers. I'm still pretty good. I can hover, go up and go down if I need to. I can do it in a dry suit, 3mm wetsuit or 5mm wetsuit.
A moment about buoyancy. Travis is very challenging for buoyancy. First it's dark and low-viz. Second you are descending down a 45 to 60 degree slope along a chain and it's challenging to say the least to keep the chain in site and your fins high enough to stay off the bottom behind you. We don't normally dive head first down for any length of time. Normally we train for horizontal or vertical buoyancy. Travis requires you do descend head first feet up.... I can do that, it's just more difficult then other dives where you descend horizontally or vertically.
Lastly I was diving with 10 pounds. That's a tad more than I think is needed, but it makes it easy to go down and stay down on a training dive. The most important part about weight is making sure you can hold your safety stop at 15 feet with a nearly empty tank....So I don't see any issues with the weight. In Blue Lagoon on a fun dive I'd probably have dove 8 lbs.
I see buoyancy as something that you aspire to improve. It's like meditation in my opinion. So I'm proficient at it and can avoid touching things. However, I've seen others who are better and I recognize I can be better. That doesn't mean I have buoyancy trouble.
Anyhow, Captain you are so right. I didn't get my cert to dive in duck-poo-pond or Pecan Graveyard. I got it to dive in the tropics. My Fling trip keeps getting killed for weather or now oil reasons. Your boat is on my "to-do" list.....