SMB deployment question

[BoltSnap]

"sleepies"

This is so cute, never heard this term before

 

[The Chairman]

This must be why I napped for 2 hours when I got home LOL.

The half time for your blood and neural fluids is thought to be about 5 minutes. Once dissolved nitrogen becomes microbubbles, it's harder to get rid of and gets caught in your alveoli restricting blood flow just a tad. The more time at 15-20 feet, the better! I actually try to be the last person on the boat and will only head up those last fifteen feet when I see the last of the bobbers get on the ladder. I will also sit for a minute or two after I get to my seat so I keep my pulse slow and even. Slow is sure. Sure is fast.

When I'm diving caves, I'll not only do at least five minutes at my safety stop, I'll do that on top of any deco I might have and then I'll do a five-minute rest on the surface too. I've been diving since 1969 and have never been bent. That's no accident.

 

[johndiver999]

On this dive, the capt wanted us to deploy SMB (or just inflate at surface) so he can see you better and come get you on the drift dive.

I could have made it easy for myself and just inflate on surface, but I figured inflating submerged would give me some much needed practice on deployment. I've practiced deploying from bottom on beach dives just for practice, but this is like 15-20 feet at the bottom. I hadn't done it on a 80-90 ft dive before, so these questions arose.

other issue I had was, I looked and my smb wasn't standing (just on it's side floating) so I put tension on rope to stand it, which caused me to go ascent (like climbing a rope) I also had some air in BC still, which didn't help. I will have to remember to dump some air next time.

I later realized the SMB doesn't have to be standing. just being on surface is good enough for you to get noticed (I saw other diver's SMBs when I was on surface)

I should add everyone had red SMBs, and the one person who had a yellow one was more noticable...

I would recommend that you do a normal careful ascent to around 30 feet. Then STOP there. Make sure you are perfectly neutral and stable.

Get the spool and smb configured (this should take like 30 seconds).
Blow one breath of air in the SMB (this should cause no change in your buoyancy)
When you are sure you got no tangles etc. - let it fly.
Dump a little air from the BC
Now slowly climb the string winding it in and pulling down on the float.
Stop winding around 15-20 ft, dump more air from BC and hang from the string. If you don't pull down the float will lay flat on the surface.

Then over a period of a few minutes, wind some more string in and hang around 12-15 feet. You are going to need to be about 3-4 lbs heavy (with no air in BC) to easily hang on the smb. Then slowly do the final ascent.

Don't listen to people who tell you that you need to be neutral at this depth with zero air in the BC.. it just makes it too hard to hang from the smb (and if you follow their directions, you won't be able to keep it up, and nobody likes that, especially the boat driver).

 

[Ulfhedinn]

When I deploy mine its just before accent.

 

[AdivingBel]

I shoot mine at about 40 ft…deep enough that it fills with little effort and enough room (when you’re new to it) not to blow your SS if you lose your concentration for a bit. I find shooting from much deeper just leaves more line to wind up.

I generally do a 3 min SS on a typical “tidy bowl” rec dive. I might stay longer if I’ve pushed (not exceeded) NDLs a bit. I ALWAYS go slow (sometimes 1 min+) when surfacing after my SS. I’ve seen folks do longer SS then surface like a Poseidon missile launch…NOT GOOD. Basically, the idea is to ascend from depth slowly. While SS is not mandatory on an NDL dive, it’s a good way to achieve this result.

If that’s all too complicated and you want to add some conservatism, then do a 5 min SS followed by a reasonable ascent. Bumper stickers are a good way for new divers to become old divers. All IMHO, YMMV.

 

[Jafo19D]

Extending your underwater stay by 2 minutes allows you to continue to safely offgas and minimize the after-dive sleepies.

Does it really help with getting sleepy?

 

[Jafo19D]

The half time for your blood and neural fluids is thought to be about 5 minutes. Once dissolved nitrogen becomes microbubbles, it's harder to get rid of and gets caught in your alveoli restricting blood flow just a tad. The more time at 15-20 feet, the better! I actually try to be the last person on the boat and will only head up those last fifteen feet when I see the last of the bobbers get on the ladder. I will also sit for a minute or two after I get to my seat so I keep my pulse slow and even. Slow is sure. Sure is fast.

When I'm diving caves, I'll not only do at least five minutes at my safety stop, I'll do that on top of any deco I might have and then I'll do a five-minute rest on the surface too. I've been diving since 1969 and have never been bent. That's no accident.

So this seems to support the argument that Nitrox helps fight the sleepiest right?

 

[davehicks]

On this dive, the capt wanted us to deploy SMB (or just inflate at surface) so he can see you better and come get you on the drift dive.

I could have made it easy for myself and just inflate on surface, but I figured inflating submerged would give me some much needed practice on deployment. I've practiced deploying from bottom on beach dives just for practice, but this is like 15-20 feet at the bottom. I hadn't done it on a 80-90 ft dive before, so these questions arose.

other issue I had was, I looked and my smb wasn't standing (just on it's side floating) so I put tension on rope to stand it, which caused me to go ascent (like climbing a rope) I also had some air in BC still, which didn't help. I will have to remember to dump some air next time.

I later realized the SMB doesn't have to be standing. just being on surface is good enough for you to get noticed (I saw other diver's SMBs when I was on surface)

I should add everyone had red SMBs, and the one person who had a yellow one was more noticable...

Deployment a little deeper will ensure the smb is fully inflated. At 50-60 feet the gas will expand by more than 100%. Deployment at 15-20 feet is going to be difficult to get it full without it hauling you to the surface.

 

[Mr. Sunday]

I like to shoot mine around 35-40'. Makes for a full inflate and I can slowly start to work my way up the line to my stop.

 

[johndiver999]

Deployment a little deeper will ensure the smb is fully inflated. At 50-60 feet the gas will expand by more than 100%. Deployment at 15-20 feet is going to be difficult to get it full without it hauling you to the surface.

It all comes down to how much time you want to waste/expend winding in line. Sending it from 60 feet means you are going to be winding for a long time. Not something I find enjoyable, but there is nothing wrong with doing it deeper. In reality, it generally doesn't really matter if the smb is fully inflated or not, what matters is that it has a good bit of air in it and the diver can put enough tension on it to keep it standing upright.

If, when the safety stop is over and the diver has made it to the surface and the boat is not around, THEN it may be important to inflate the smb to the maximum in order to make it easier to see, but in most drift diving situations, if the smb is on the surface when expected and it is sticking up, the boat should be able to find it.