Cville_Diver
New
My son and I went for a fossil dive on the Cooper River in SC with Johnny Cercopely at Cooper River Dive Charters. This was our first black water experience and I thought it might be useful to others considering a similar dive. Johnny runs his own boat and does 3-tank charters.
Initial prep:
Before we went, I tried to research the dive conditions and prepare. I picked up mesh collection bags, made spikes, checked the SMBs, and double checked the batteries in our lights. I also applied for the mandatory South Carolina Hobby License for collecting artifacts and fossils ($500 fine for not having one). It took about 3 weeks to get the license, but it was only $10.
The experience:
Viz was everything that was promised, which is to say almost nothing. In the current, I could make out my buddy's light from around 3 feet. The best viz we had was maybe 2 feet and to see anything clearly it was about 1 foot. This made physical contact on descent and ascent critical. All it took was a moment to lose sight of each other.
The spike turned out to be essential in the current. I picked up a couple of 8" Phillips-head screwdrivers and some paracord. I drilled the handles and made lanyards. These worked well even when the current picked up significantly. I could feel the shaft flex at one point, but once it was set into the clay bottom it was solid. When the current picks up, it really moves. I was hanging on to the spike pretty hard during one dive.
The water temp was decent (about 83 deg. F) and fairly consistent to the bottom, as you would expect in moving water.
Lessons learned:
Gear, first. I believe a marker light on the tank strap is essential. I swear by those on night dives (especially over chemical lights) and it was essential in the murk since a flashlight was invisible unless it was pointed almost directly at the other diver.
When we go back, I will be taking more and stronger lights. We had UK C4 eLED pistol grip lights, which are only 575 lumens. That was fine, but more light would be better. Our backup lights were almost useless. Also, take extra batteries just in case.
Since you're lying on the bottom bumping or crawling along, fins don't do a lot. Knee pads, on the other hand, would have been a good idea. I may pick up a cheap set from the hardware store for the next time.
The collection bag. This is a personal preference thing, but I found that a mesh bag, even a smaller one, got dragged in the current. I felt like I was constantly fumbling to get it open and put items inside. Other folks had homemade canisters (PVC pipe with a drilled end-cap and a rubber opening) or stuffed the items in their pockets or suit. In the future, I might leave the bag behind or just use it for the rare larger item.
Air management. The low vis made checking the SPG more of a challenge as you can't just glance at the dial but instead you need to bring it close to your face and light it. (Those with LED gauges may not have this problem.) This was made even more difficult in the current where I was holding on the spike at the same time. This may be something where checking your buddies SPG is easier than checking your own, as long as you communicate with each other. At depths of around 30 fsw, we generally had over an hour per dive on an AL80 tank and it was easy to lose track of time.
[Edit: added section on weight] At the recommendation of others, we dove overweighted. I was about 6 lbs. heavy (I'm not a big guy). I'm not positive this was necessary for me and I really dislike being overweighted. It freaks me out on ascent. Since you're spending your time on the bottom, I understand the reasoning. In the future, I think I'll reduce the weight to something closer to my usual.
Finding items:
This is where I really need to improve. Digging in the muck is generally a waste of time. Moving around and looking at the accumulations of gravel is the best plan (hence the benefit of more light). I was not the best at identifying shark teeth and other items from the rocks. The best plan is to pick up anything that looks interesting and figure it out on the boat.
Even with no prior experience, we found shark teeth, including some large fragments and a number of smaller intact teeth. My son also came up with a pottery shard from the late 1800s and an intact whisky bottle from the late 1800s or first years of the 1900s. The more experienced guys on the boat came up with fossilized mammal teeth, many more shark teeth, and even a knapped flint spearpoint.
We did come across shrimp and juvenile flounders on the bottom and at one point I saw a fish (unknown type) and a small eel at the edge of my light. With such poor viz, you won't see much. If you're claustrophobic or get spooked on a night dive, you should know that this is similar. The shrimp, in particular, would suddenly pop into view, often just inches from my mask. I didn't mind, but I could see how this could spook some people.
Tl;dr:
This was completely unlike other diving. Very little swimming, mostly crawling or anchoring to the bottom. Very low viz. Don't count on finding too much your first time. 10/10 - will go again.
Initial prep:
Before we went, I tried to research the dive conditions and prepare. I picked up mesh collection bags, made spikes, checked the SMBs, and double checked the batteries in our lights. I also applied for the mandatory South Carolina Hobby License for collecting artifacts and fossils ($500 fine for not having one). It took about 3 weeks to get the license, but it was only $10.
The experience:
Viz was everything that was promised, which is to say almost nothing. In the current, I could make out my buddy's light from around 3 feet. The best viz we had was maybe 2 feet and to see anything clearly it was about 1 foot. This made physical contact on descent and ascent critical. All it took was a moment to lose sight of each other.
The spike turned out to be essential in the current. I picked up a couple of 8" Phillips-head screwdrivers and some paracord. I drilled the handles and made lanyards. These worked well even when the current picked up significantly. I could feel the shaft flex at one point, but once it was set into the clay bottom it was solid. When the current picks up, it really moves. I was hanging on to the spike pretty hard during one dive.
The water temp was decent (about 83 deg. F) and fairly consistent to the bottom, as you would expect in moving water.
Lessons learned:
Gear, first. I believe a marker light on the tank strap is essential. I swear by those on night dives (especially over chemical lights) and it was essential in the murk since a flashlight was invisible unless it was pointed almost directly at the other diver.
When we go back, I will be taking more and stronger lights. We had UK C4 eLED pistol grip lights, which are only 575 lumens. That was fine, but more light would be better. Our backup lights were almost useless. Also, take extra batteries just in case.
Since you're lying on the bottom bumping or crawling along, fins don't do a lot. Knee pads, on the other hand, would have been a good idea. I may pick up a cheap set from the hardware store for the next time.
The collection bag. This is a personal preference thing, but I found that a mesh bag, even a smaller one, got dragged in the current. I felt like I was constantly fumbling to get it open and put items inside. Other folks had homemade canisters (PVC pipe with a drilled end-cap and a rubber opening) or stuffed the items in their pockets or suit. In the future, I might leave the bag behind or just use it for the rare larger item.
Air management. The low vis made checking the SPG more of a challenge as you can't just glance at the dial but instead you need to bring it close to your face and light it. (Those with LED gauges may not have this problem.) This was made even more difficult in the current where I was holding on the spike at the same time. This may be something where checking your buddies SPG is easier than checking your own, as long as you communicate with each other. At depths of around 30 fsw, we generally had over an hour per dive on an AL80 tank and it was easy to lose track of time.
[Edit: added section on weight] At the recommendation of others, we dove overweighted. I was about 6 lbs. heavy (I'm not a big guy). I'm not positive this was necessary for me and I really dislike being overweighted. It freaks me out on ascent. Since you're spending your time on the bottom, I understand the reasoning. In the future, I think I'll reduce the weight to something closer to my usual.
Finding items:
This is where I really need to improve. Digging in the muck is generally a waste of time. Moving around and looking at the accumulations of gravel is the best plan (hence the benefit of more light). I was not the best at identifying shark teeth and other items from the rocks. The best plan is to pick up anything that looks interesting and figure it out on the boat.
Even with no prior experience, we found shark teeth, including some large fragments and a number of smaller intact teeth. My son also came up with a pottery shard from the late 1800s and an intact whisky bottle from the late 1800s or first years of the 1900s. The more experienced guys on the boat came up with fossilized mammal teeth, many more shark teeth, and even a knapped flint spearpoint.
We did come across shrimp and juvenile flounders on the bottom and at one point I saw a fish (unknown type) and a small eel at the edge of my light. With such poor viz, you won't see much. If you're claustrophobic or get spooked on a night dive, you should know that this is similar. The shrimp, in particular, would suddenly pop into view, often just inches from my mask. I didn't mind, but I could see how this could spook some people.
Tl;dr:
This was completely unlike other diving. Very little swimming, mostly crawling or anchoring to the bottom. Very low viz. Don't count on finding too much your first time. 10/10 - will go again.
