Or it's an extra safety
margin for an experienced diver when out in unfavorable conditions, or when not diving in calm, clear, warm water.
I'm with you on just how bad some diver's skills are. Those types annoy the **** out of me, well and sometimes really entertain me. I'll often blow past all the cattle hanging on the line and do a free ascent just to keep away from them...and to beat them back to the boat.
You're not going to see too many, if any, once a year tourist types diving off Jersey.
No, not necessarily hand over hand, although it has been known to happen, but we are talking about diving further off shore and in potentially unfavorable conditions.
Minimum is usually about 5 miles out, I'd say 10 is probably the average, with many dives also in the 20 mile range.
Potential for current, but more likely surge and/or high seas. I saw a buddy get caught in such a strong surge on a wreck once that from below it looked like he was reenacting a scene from a Kung Fu movie
. (Rolled over the top and blown right over the other side.)
Sometimes a layer of as we like to call it pea soup, close to the surface making the lines, the boat, the surface, the wreck, the bottom of the ocean all hard to see until you're pretty close.
Cold water, while in the summer often very hot on the surface, adding more potential for fatigue and or heat exhaustion. I was once out where it was mid 90s on the surface, low 50s at depth
, with 5' seas. Most of the divers bailed on the second dive simply because of heat exhaustion.
Doesn't matter how good your skills are or how big and strong you are, when conditions suck you're going to get tossed around like a rag doll. This rig simply makes it safer, easier, and faster to get out of unfavorable surface conditions.
So, if we're talking Caribbean
, I'll agree it is kind of a crutch, but up here if a boat doesn't have at least a granny line then it's an accident
waiting to happen.
The Carolina rig is even better, because in high seas, it allows you to easily get down and out of the way of a rolling boat. I have a friend who dives the Empress every year, who's actually making one for the boat they use. He told me the biggest reason for aborted dives are people getting the **** kicked out of them by the boat on the surface.
One of my first local dives I bailed on, after I started hyperventilating at 15' and couldn't get any air from my reg. Although I was a newbie and nervous, to this day I think the biggest cause was just exhaustion from descending along a granny line in rough seas, while trying not to get slammed by a rolling boat, and eventually getting my bailout tangled in the granny line, which was hard to avoid due to the degree to which I was getting tossed around. A Carolina rig would have allowed me to drop straight down, to 15-20 feet without getting caught in that line, and I very likely would have completed that dive. No, there wasn't much current, but doing a free descent, in 70', 7 miles out, in not the greatest vis, at night is just stupid.
Maybe I'm overdramatizing, there are many days where it's beautiful out there. Calm seas and great vis. But it can change fast, and the conditions I noted above aren't uncommon. So do you plan for those nice days or do you prepare for the worst?
Lastly - I'm a cat with a single
i/o, so it's very unlikely the rig would get caught in my prop.