First Spiegel Grove dives and lessons learned

[Eric802]

More likely is that the OP has his safety stop setting set to Adapt. If so & you go below 100’ or 5 min of NDL, it gives you a 5 min safety stop. This is still a non-mandatory stop unlike a deco stop.

View attachment 898970

That’s correct. I never passed my no-deco limit on either dive.

 

[Eric802]

*snip*
Hope is not an effective strategy. CDR allows solo diving (well that may depend on the Captain- Mark was filling in the day I last dived with them and at first said no to solo but relented when I put up a fight) but with most dive charters if you've got the certification, the skills, the gear, and the experience you don't need to be hooked up with a liability.



You need to work on this. It might not matter so much on the SG that has at least a half dozen mooring balls from bow to stern, typically with watchful dive boats on a few of them, but on other dives it can make the difference between life and death. The steel 100s could have made the difference here (if you chose to look at your spg) but that would have been a matter of gear making up for poor planning and skills. Carry a reel and dsmb and know how to use them.

Well, inherent in the "instabuddy" concept is the fact that you can't plan for what you get; since I was the only diver in our group, I didn't have much choice. If I had the "certification, the skills, the gear, and the experience" I certainly would've gone solo but if I had all that, my post here would probably read quite a bit differently. The crew did ask me if I wanted to go solo, but the first follow-up question was "do you have a redundant air supply?" and that was a no. In hindsight, obviously, it would've been quite a mistake to go solo (although I probably would've stayed closer to the downline just out of caution). Getting a solo cert and the associated gear is on my list, though.

I did have a reel and DSMB and can deploy it easily.

 

[crofrog]

Here is an introduction to how we'd plan this dive with GUE methodology, it's an intentionally conservative approach.


Step 1: Calculate Minium Gas

• Consumption Rate (SAC): 0.85 cuft/min per diver × 2 divers = 1.7 cuft/min total (we normally plan with .75 but your observed consumption was higher so that should be used)
• Average ATA (Atmospheres Absolute): ((70 ft / 33) + 1 + 1) / 2 = 2.05 ≈ 2 ATA
• Ascent Time: (70 ft ÷ 10 ft/min) + 1 min = 8 minutes (includes 1 min for problem solving)

Gas Calculation:
1.7 cuft/min × 2 ATA × 8 min = 27 cuft

Convert to Tank Pressure:
27 cuft ÷ 2.5 (AL80 tank factor) × 100 = 1100 psi


Reserve Needed: 1100 psi to safely get two divers to the surface from the bottom on one tank in an emergency.

Step 2: Determine Usable Gas and Turn Pressure

• Tank Start Pressure: 3000 psi
• Min Gas Pressure: 1100 psi
• Usable Gas: 3000 - 1100 = 1900 psi
• Round Down for Easy Division: 1800 psi
• Rule Used: Halves (appropriate for dives like Spiegel Grove where surfacing anywhere is viable)

1800 psi ÷ 2 = 900 psi usable for penetration

Turn Pressure:
3000 - 900 = 2100 psi

At 2100 psi, both divers should turn and begin returning to the ascent line or exit.

Step 3: Estimate Bottom Time (Outbound Swim)

• Gas Available for Outbound Swim: 900 psi
• Convert to Volume: 900 ÷ 100 × 2.5 = 22.5 cuft
• ATA at 70 ft: (70 ÷ 33) + 1 = 3.1 ATA
• Depth SAC: 0.85 × 3.1 = 2.6 cuft/min
• Outbound Time: 22.5 cuft ÷ 2.6 cuft/min = ~8.6 minutes

You can swim outbound for approximately 8.6 minutes before reaching your turn pressure.

If you'd like to replan the dive with what a 100cuft tank would look like the tank factor for that tank is 3.
100cuft/3442*100 = 2.9

 

[gamon]

The crew did ask me if I wanted to go solo, but the first follow-up question was "do you have a redundant air supply?" and that was a no.

Conch Divers is not going to allow solo diving without the certification. Had you answered yes to the redundant air supply question, the next thing the crew would have said would have been "Ok, great go inside the shop and show your solo card and sign the solo diving waiver".

 

[kcc6001]

Dove the SG last time for the first time and covered 10-15% of the deck of the wreck. I honestly can't imagine tackling it without a dive guide. The currents were no joke but I can appreciate not knowing where your mooring line is between the size of the wreck, currents, and the "crowds". But you also get this...

 

[Divin'Papaw]

Conch Divers is not going to allow solo diving without the certification. Had you answered yes to the redundant air supply question, the next thing the crew would have said would have been "Ok, great go inside the shop and show your solo card and sign the solo diving waiver".

Horizon is the same. Happy to allow solo if properly certified and equipped.

 

[gamon]

Horizon is the same. Happy to allow solo if properly certified and equipped.

Horizon is my go to dive charter after CDR. The reason they're second is because 1) they don't have steel 100s only a handful of those jumbo sized AL100s that may be available upon request, first come first served (and I haven't been fortunate in that regard) and secondly because CDR will allow the first diver who makes a booking to choose their dive sites and I like to get on the Duane periodically, as well as the Eagle (which is too far South for Horizon and several other popular Key Largo based charters).

 

[coldwaterglutton]

I was very frustrated on the SG last month when I dove with my son. The surface currents were really ripping, probably in the neighborhood of near 2 knots.

At 17 feet my son and I both hooked our jon lines to the mooring line for a 5 minute hang. One other diver decides to deploy a jon line in exactly the same place and then he becomes braided with my sons line, leading to a need for disentanglement. Then about 5 other divers coming up chose to cluster right on our hooks, one of whom puts a hand directly on my garvin hook knocking it off the mooring line. Thankfully I was holding hands with my son at the stop or I would have been blown out and needed to be recovered. As it was it took a major hand over hand scramble to get back on the line to ascend.

This, and another major issue that happened to another diver that I don't want to recount, and I won't go back to any of the Key Largo sites unless I charter a private boat.

 

[gamon]

This, and another major issue that happened to another diver that I don't want to recount, and I won't go back to any of the Key Largo sites unless I charter a private boat.

Why say a major issue happened and then say you don't want to recount it? Just don't mention it in the first place.

Anyway, over 100s of wreck dives including on the SG, sometimes with up to 20 divers on the line, I never saw a need to complicate things with a jon line and never even heard of a garvin hook until you mentioned it. Large groups of divers can spread out over a depth range of 12-25 feet or whatever and they'll all be just fine when they hop back on the boat and untangle any lines that became inadvertantly knotted in the process.

I'm thinking you're a wee bit sensitive to a relatively minor issue at a shallow 17', that much said if you can't find yourself a private boat (where would you), you're better off diving with smaller groups such as Conch Divers rather than Rainbow Reef (for example).

I suppose you could pay exorbitant rates for a 6 pack such as Quiescence but that's an expensive solution to a non-issue especially if you don't fill the boat.

 

[coldwaterglutton]

Why say a major issue happened and then say you don't want to recount it? Just don't mention it in the first place.

Well I didn't want to because it was gross, but here it is. A diver got sick after reboard, all over the deck at his seating station. Mate sent him to the back of the boat, then proceeded to start washing the throw up with a 5 gallon bucket. Which got the throw up massively all over two other guys' gear who were down the deck. Guys were upset, and mate didn't apologize at all. Which then almost led to a full blown fisticuffs between one of the guys and the mate until the captain intervened. I thought it was going to be a full on brawl.