Who Uses their SMB and Deploys it At Depth Before Ascending to the surface

[danvolker]

And I say your thinking is seriously lacking perspective outside of the enviroment in wich you do most your diving..

I have an SMB, and I never said divers should not deploy them.... I said they should not trust the SMB to ward off boats.....That is true in Florida, and if I was in Norway, I would not trust boaters either.
You are free to trust boaters anywhere you like.

 

[pocky21]

It's not just boaters - sometimes other divers too. I rigged mine as a lift bag one time to haul in an anchor I found, and when I surfaced there were divers coming out to "rescue" me! I can recall no less than 5 other times where I got back to shore and was asked if everything was alright.

I'll deploy on 4/5 dives just to drill, though. I'll refrain if I'm on a boat with an up-line to avoid confusion with the crew.

 

[AfterDark]

My SMB has a dive flag sewn onto it. If I start the dive w/o a flag I deploy the SMB at the end in case the DEM is waiting. Most of the time they'll wait until you come out of the water to challenge you on a dive flag. Well I'm standing there holding a SMB with a dive flag dive "yes sir I have a dive flag right here". Did you have that when you started the dive? Yes sir I did. What can they do / say? We often dive from a boat in heavy boat traffic areas like Castle Hill. I'll deploy the SMB w/ dive flag, do the SS, surface and swim back to the boat towing the SMB/flag.

 

[Peter69_56]

The OP and most of the divers learning the SMB deployment skill, seem to think the SMB will magically ward off errant boaters that would otherwise cross over your head at full speed....This is seriously defective thinking.


What about a very slow boat approaching? The question would be why would they be going slow way out over a reef? In any event, the diver skill that is critical here, is the LISTENING SKILL. That at the 20 to 10 foot stop, the divers are listening for boats, and gauging how busy the surface is with boaters.

The skill needed, is knowledge of what the doppler shift sound is like, that differentiates a boat coming toward you--from one motoring away from you....and the skill in deciding if the boat noise you hear is a boat that is very close, or a very long way away.

In my own drift diving, on the dives I have done when not towing a surface float ( for my boat to follow), at my ten foot stop, I am listening for the point where I hear no boats in any effective range to run over us, and then when this moment is reached, I do a deflation of the wing/bc to negative, and then swim up hard and fast to the surface, doing a 360 degree spin and scan as I surface. On surface, the 360 scan will instantly alert me to any boats approaching--if I had an smb deployed, I would need to be doing exactly the same scanning. If there is a rapidly approaching boat, my wing/bc is already deflated, so I can jack knife and instantly be down to 10 feet in a second or two.

Normally I tow a float, and I have a skilled charter boat captain and crew scanning the horizons for me, and warding off boaters, so I don't need to worry about this potentially impending threat.

With a thread like this, it sounds like there is no charter boat patrolling, and that the OP believes the smb will ward off boats.....This is patently untrue.

This post was in response to a post I read of a woman who near had her knee cut off from just such an accident. The boat that caused it was THEIR dive boat. AS she surfaced he started the motor and moved forwards and hit her. had she of used an SMB there was a fair chance that she would not have been hit.

I agree the SMB is not a big protective shield warding off everything around you, however it does give a moving boat "some" chance to see you and give prior warning before you break the surface.

With regard to the noise, the woman did not hear anything, she is unsure why, perhaps because of many boats in the area, perhaps because he started the engine and wasn't moving at speed, but in any regard, saying you WILL hear every engine and boat is like saying an SMB will prevent every collision. She had a hood on and perhaps this also restricted her hearing.

With regard to shooting for the surface quickly to get up and look around, I see as crazy and could cause an embolism or the bends. The last 5 metres of the dive should be the slowest ascent. ALL diving related comments recommend this. I would never shoot to the surface from 5 metres and in particular after doing a long decompression dive. I would always have my SMB deployed and come up slowly.

Often the charter boat is anchored up and divers have drifted away from the anchor or down line, hence the need for an SMB for location and better protection. Its expected in many places in OZ to deploy your SMB if not coming up an anchor line. Also one guy on a boat drifting with you can only see a limited area and so every bit above the water helps this process.

As I said previously, an SMB is not a protective canopy, however it is better than a black hood in dark water.

So then let me ask another question, who thinks shooting to the surface from your safety stop or last deco stop is a good thing so as not to be hit by a boat on the move? personally I think not and would never recommend that to anyone. It might (and I say might) save you from the boat, but the increased risk from a dive related illness is much greater.

But that is only my opinion and you clearly have a different approach. I guess I will dive my way and you yours.

 

[Searcaigh]

Depends. If you pop it right next to your moored dive boat, the crew might mistake it as a distress signal. I've had the rescue diver suddenly show up and check on me when I did that just for practice and forgot to tell them ahead of time.

Boats carry rescue divers

 

[tphelps]

An audible and visual marker are required materials for dive professionals. This could be a whistle or DSMB. I personally have both on me all the time, even when I am just "fun diving." I believe DSMB skills are very important. Deploying them are required when we come up off a rebreather dive.

 

[GrimSleeper]

This post was in response to a post I read of a woman who near had her knee cut off from just such an accident. The boat that caused it was THEIR dive boat. AS she surfaced he started the motor and moved forwards and hit her. had she of used an SMB there was a fair chance that she would not have been hit.

I agree the SMB is not a big protective shield warding off everything around you, however it does give a moving boat "some" chance to see you and give prior warning before you break the surface.

With regard to the noise, the woman did not hear anything, she is unsure why, perhaps because of many boats in the area, perhaps because he started the engine and wasn't moving at speed, but in any regard, saying you WILL hear every engine and boat is like saying an SMB will prevent every collision. She had a hood on and perhaps this also restricted her hearing.

With regard to shooting for the surface quickly to get up and look around, I see as crazy and could cause an embolism or the bends. The last 5 metres of the dive should be the slowest ascent. ALL diving related comments recommend this. I would never shoot to the surface from 5 metres and in particular after doing a long decompression dive. I would always have my SMB deployed and come up slowly.

Often the charter boat is anchored up and divers have drifted away from the anchor or down line, hence the need for an SMB for location and better protection. Its expected in many places in OZ to deploy your SMB if not coming up an anchor line. Also one guy on a boat drifting with you can only see a limited area and so every bit above the water helps this process.

As I said previously, an SMB is not a protective canopy, however it is better than a black hood in dark water.

So then let me ask another question, who thinks shooting to the surface from your safety stop or last deco stop is a good thing so as not to be hit by a boat on the move? personally I think not and would never recommend that to anyone. It might (and I say might) save you from the boat, but the increased risk from a dive related illness is much greater.

But that is only my opinion and you clearly have a different approach. I guess I will dive my way and you yours.

I carry at least one DSMB on every dive, but the accident you describe would equally have been avoided if (a) the boatman had the training/common sense not to move a live boat if he wasn't absolutely certain where the divers were and/or (b) the diver had had the sense not to approach the surface directly under a live boat. So a bag might have prevented the incident, but so might thought and care.

If surface conditions are rough, or currents are carrying us away from where we - and the boat - expect us to be at the end of the dive, I'll shoot a bag. Otherwise, I'm looking at the fishies at 5m until it's time to surface, and a DSMB is just a hassle.

Why wouldn't you shoot a bag from safety stop depth, other than the greater effort required to get enough air into it to make it stand up? Unless I'm carrying out a blue-water drift deco (in which case I want a marker up ASAP so the boat doesn't lose me - there's Oceanic Whitetips out there...), why would I want to tow a DSMB about unnecessarily? The risk of a 'dive related illness' is only increased if the diver has poor buoyancy control, in which case they shouldn't be doing dives that give them the kind of inert gas loading that might make popping to the surface from 5m inherently dangerous.

And as for boaters and surface markers... Did a dive in Thailand once on which we were briefed that, because of boat traffic, every buddy pair had to put up a DSMB. Which meant that the jet-ski cowboys had a great slalom course...

 

[Peter69_56]

The risk of a 'dive related illness' is only increased if the diver has poor buoyancy control, in which case they shouldn't be doing dives that give them the kind of inert gas loading that might make popping to the surface from 5m inherently dangerous....

I can only go by what I have read everywhere and to date everything has suggested the last 5 metres to be critical in ascending slowly. I think to quote DAN and they said something like "60% of divers have an ascent rate of around 60m/min in the last 5 metres" or something in the order of this anyway. The implication was that this increased risk. Everything I have been taught has suggested that that last 5 m be the slowest, so have I been taught wrong by a number of different instructors and agencies (SSI, PADI, TDI)?

With regard to using an SMB for every ascent when not on a line, clearly (and I was not aware of this), there are different rules depending on your global location. In OZ, generally its simply a marker for submerged and surfaced divers, nothing more. I was not aware that in other countries (USA?) that is a form of emergency indication. Is my new understanding of this correct? If so I stand corrected.

To date I have used them in OZ, Fiji, Vanuatu, Bali, Sipidan, Brunei and in every place they were considered just a marker and not indicate an emergency. I have a yellow one as well and I only use that as an emergency marker when tech diving but tell the boat crew before hand so they understand. It has a slate attached so a message can be sent to the surface indicating the emergency.

Anyway the post has certainly promoted significant response and I have also learned some things I didn't know and will endeavour to tell the boat crew before I dive, in particular when overseas. Thank you fellow divers.

 

[GrimSleeper]

I can only go by what I have read everywhere and to date everything has suggested the last 5 metres to be critical in ascending slowly. I think to quote DAN and they said something like "60% of divers have an ascent rate of around 60m/min in the last 5 metres" or something in the order of this anyway. The implication was that this increased risk. Everything I have been taught has suggested that that last 5 m be the slowest, so have I been taught wrong by a number of different instructors and agencies (SSI, PADI, TDI)?

Obviously, rocketing to the surface from 5m does potentially increase the risk of DCS. That risk is, however, compounded by higher gas loadings in tissues. My point was that, if a diver doesn't have the buoyancy control and technique to safely deploy a DSMB from 5m (and it really isn't that hard), then perhaps they shouldn't be doing dives that leave them with a high gas loading. Going from 5m to the surface in five seconds is considerably less dangerous after 40 minutes at 10m than it is after a 40-minute multi-level dive to 30m, or a staged deco dive with 30 minutes of bottom time at 55m, by way of random example. And, frankly, if someone can't safely deploy a bag from 5m, would you want them deploying from 30m and risking being dragged all the way to the surface at high speed from there? I'm just suggesting that the answer lies in technique, rather than in saying that it's OK to deploy from deep but not shallow.

 

[Peter69_56]

Obviously, rocketing to the surface from 5m does potentially increase the risk of DCS. That risk is, however, compounded by higher gas loadings in tissues. My point was that, if a diver doesn't have the buoyancy control and technique to safely deploy a DSMB from 5m (and it really isn't that hard), then perhaps they shouldn't be doing dives that leave them with a high gas loading. Going from 5m to the surface in five seconds is considerably less dangerous after 40 minutes at 10m than it is after a 40-minute multi-level dive to 30m, or a staged deco dive with 30 minutes of bottom time at 55m, by way of random example. And, frankly, if someone can't safely deploy a bag from 5m, would you want them deploying from 30m and risking being dragged all the way to the surface at high speed from there? I'm just suggesting that the answer lies in technique, rather than in saying that it's OK to deploy from deep but not shallow.

Sorry I missed your point. I thought you were suggesting it was ok to go from 5m to the surface at an accelerated rate, which someone else suggested they did as a matter of course. I agree totally with your comment.