Lift bag for ascent?

[DA Aquamaster]

Actually, you'll need a whole lot more than 150 feet unless you're in a dead still quarry or lake. If you've got so much as a hint of current, your line is going to be pulled sideways as the bag ascends.

That is true with an upline where one end of the line is fixed but not neccesarily the case when shooting a lift bag for a drifting ascent unless you have a large variation in current between the bottom and the surface. You just need to come up off the bottom a few feet and go with the current.

 

[String]

Near all dives here are terminated with a DSMB ascent. Low vis and strong currents mean getting back to the shot line is far from easy plus it limits how far you can travel on a dive before turning around.
In a strong current they make deco stops far more comfortable as you are drifting with it not doing a flag impression on a crowded shot line.

Boats also never anchor - again due to conditions.

Even novice divers are trained in DSMB use and most clubs and boats make it mandatory for every diver to carry one.

The DSMBs are usually deployed either a few minutes before leaving the bottom or on leaving the bottom. Some people prefer to deploy them mid ascent but before their stop depth as well. There are several combinations.

Most DSMBs have roughly 30lb or so lifting capacity, overpressure and dump valve and are self sealing making things much easier - they can be used as simple lift bags if needed.

Drift dives are an exception as the bag is towed throughout the dive so the boat can keep track of its divers.

 

[String]

UWS-Not getting back to the anchor line should only happen due to circumstances that are out of your control.

Disagree totally. Maybe thats how boats work in the USA but its certainly not world wide like that. Its extremely rare here to see a boat anchor at a dive site and rare to see divers come up a boat dropped shot line.
Not everyone plans to come back to a boat anchored in calm conditions and/or good visibility.

An ascent with a marker buoy should be considered a last resort emergency type procedure, not a substitute for consistently finding your way back to the anchor line.

Disagree again. If the PLAN is to return to an anchor line then you should attempt it. Ive never had a dive here where that has been the plan yet though.

 

[Uncle Pug]

Perhaps ScottyK's advise is taylored more to his diving area on the East Coast USA.

Here in the PNW-USA (where the thread starter lives) it is not generally the case that one needs to make it back to the anchor line. Charter boats are live and pick up the divers. Lift bags if used will behave differently that DA Aquamaster suggests too.

We will anchor our boat if the current at the site permits... if not then we try to live boat as well. But even with an anchored boat we don't always make it a practice to get back to the anchor line.

Learning free ascents without a line for reference is a good thing. The only reason to shoot a bag is to let a live boat know where you are drifting or if in an area with a lot of boats to warn them of your position. This actually can work against you because some of them are tempted to come look at the orange thing sticking up out of the water!

Often here the currents run different at the bottom than at the top and the wind can carry a liftbag/divemarker along at a good clip as well.

Last Thursday we did an anchored boat entry in current and once on the bottom (where the current was nil) we released the anchor. The fellow running the boat for us pulled it in and waited. At the end of our dive I shot a bag (using a spool) to mark our drift. Normally I would have let the spool hang by itself without touching it until winding it in between stops but this time the wind was pulling the bag so fast I had to hang onto it the whole time. The line was at a 45 degree angle!

Actually I would have been better off not to shoot the bag at all and just inflate it as a surface marker after we made our ascent.

 

[ScottyK]

Disagree totally. Maybe thats how boats work in the USA but its certainly not world wide like that. Its extremely rare here to see a boat anchor at a dive site and rare to see divers come up a boat dropped shot line.
Not everyone plans to come back to a boat anchored in calm conditions and/or good visibility.

Disagree again. If the PLAN is to return to an anchor line then you should attempt it. Ive never had a dive here where that has been the plan yet though.

Actually, if you go back and read the original post I was responding to, the problem was that he was "planning" to get back to the anchor line and having trouble finding it.

If your plan does not include getting back to the original descent line then it's obviously not a problem if you don't. You're disagreeing with something I didn't say, and implying that I said every boat dive must end with an anchor line ascent. I'm pretty sure I never said that either.

You are taking my answer completely out of context.

 

[String]

That certainly isnt how i view it.

The original post mentions nothing about planning to go back to a shot or anchor line.

Only on the 3rd post does he mention a few dives failing to get back to the line, the original question made no mention at all of it.

An ascent with a marker buoy should be considered a last resort emergency type procedure,

Is a highly drastic description of a very simple procedure. I cant see any reason why deploying a DSMB constitutes an emergency. At worst its a minor inconvenience.

 

[ScottyK]

A number of times I haven't found the anchor and needed to go up.

This is the quote at the top of my original reply. If you state that you haven't "found" something, then you must be looking for it. The correctness of my assumption was borne out by the reply I got from UWS. He was having trouble finding the anchor line. I'm also not sure why it matters that it was his third post as I didn't get involved in the conversation until after that third post.


You also mentioned previously that you don't do any diving where an anchor line ascent is normally required. These types of dives are normally done in areas where strong currents and heavy/unpredictible seas are common. This is also the norm when some or all of the divers are doing deco stops, or will not be surfacing in a group. In these situations my description not at all drastic.

Coming up away from a boat that can't leave the divers who are decompressing or still diving to go chasing after you is also no minor inconvenience. I've seen divers miss the line, pop a marker buoy to make a free ascent, and be completely out of sight of the boat in less than 5 minutes. Luckily for them the crew kept a good eye out, and noticed the marker and which way it was heading.

 

[String]

All my dives are in areas with currents and usually strong seas which is exactly why boats dont anchor , divers cant make it back to the boat or line due to currents and its not safe to be moored in the first place.

Also a lot of dives here are decompression dives.

Nearly ALL are terminated on a DSMB and the few that arent using a shot line. Divers are also never in a group and nearly always in a 2 man independent pair.


Only abroad in calm seas/good vis have i ever seen boats moored and anchor line ascent/descents being normal. In those benign conditions its easy to either find the line or surface swim to it.

IF you are briefed you must return to the shot line or anchor line and constantly fail to find it you need to work on skills. If you miss it very rarely then its not the end of the world if you have to pop a bag up.

 

[ScottyK]

All my dives are in areas with currents and usually strong seas which is exactly why boats dont anchor , divers cant make it back to the boat or line due to currents and its not safe to be moored in the first place.

You're talking about drift diving, which as I previously stated, is completely out of the context of my original reply.

There are plenty of situations where a boat will need to anchor in less than perfect conditions. You don't normally drift dive a wreck, or a site where there is a specific place you want to go. It's done regularly and safely every day. One of the skills that make it safe to do these kind of dives is "getting back to the anchor line before surfacing". This way you can hit a specific target area, and not have to deal with the dangers of big swells and faster currents at the surface.

This is the normal procedure where I dive. If the dive boats only went out in flat conditions, I'd get in about two dives a year Since UWS was dealing with the same situation, it stands to reason that the boat he was on called for a planned anchor line ascent. From there the logical conclusion is that the boat captain had good reason to do so.

BTW- I have no problem having a healthy intellectual discussion with a fellow diver. Thanks for keeping this civil, which is refreshing. I think if you get the opportunity to do some diving from an anchored boat in the conditions I'm describing you'd have a better understanding of where I'm coming from.

I've done some wonderful wreck dives off the east coast here. I have however had days where after arriving and entering in relativly benign conditions, I've come back up to a completely different ocean after a short 45 minutes or so. When the swells and current get rolling good, you can barely see even a tall marker buoy that's relatively close to the boat. I don't care how I accomplish it, whether it's via a reel or uber-navigating, I'm getting back to my original entry point if the boat is anchored.

 

[String]

You're talking about drift diving,

No im not. Im talking about ALL the diving. Drift diving is conducted with an SMB inflated on the surface or a DSMB inflated immediately after starting the dive and is towed the whole dive. This is down when very large distances are expected to be covered during the dive (can be several miles)

There are plenty of situations where a boat will need to anchor in less than perfect conditions. You don't normally drift dive a wreck, or a site where there is a specific place you want to go.

No you dont but i wasnt on about drift diving. Even sites timed for slack water or protected have underwater and surface currents. These surface currents are often impossible to swim against.

It's done regularly and safely every day. One of the skills that make it safe to do these kind of dives is "getting back to the anchor line before surfacing". This way you can hit a specific target area, and not have to deal with the dangers of big swells and faster currents at the surface.[/quote'

As i said before that isnt normally possible given the tides changes, resulting currents and low visibility. Add that to the face having to return to a line can shorten the amount of time you can spent exploring the area by near 50% as you have to turn back. Combine that with the fact its not great policy to anchor a boat in rough seas/strong currents as its (i) not comfortable and (ii) its response time if needed to get to a diver in trouble or pick up a drifting pair is massively reduced.

This is the normal procedure where I dive. If the dive boats only went out in flat conditions, I'd get in about two dives a year

Thats probably the same number id get. The sea here is never flat, never calm and the weather is normally poor as well.

I've done some wonderful wreck dives off the east coast here. I have however had days where after arriving and entering in relativly benign conditions, I've come back up to a completely different ocean after a short 45 minutes or so. When the swells and current get rolling good, you can barely see even a tall marker buoy that's relatively close to the boat.

Quite common here as well, the 5-6ft DSMBs are usually very visibible even when the sea is rough and ive never yet seen a boat thats had difficulty finding one PROVIDED the boat skipper has some sense and stays in the general/expected area. They can be seen from a very long way off given better conditions.

I don't care how I accomplish it, whether it's via a reel or uber-navigating, I'm getting back to my original entry point if the boat is anchored.

I find it far easier to just shoot the bag up and have a boat waiting for me when i surface. Occasionally i have to wait if another pair surfaced just before in which case we bob and drift on the surface until they're recovered then it moves onto us.