Descending on my first night dive?

[sprange]

I'm confused. Why can't you fin down those first ten feet at night?

He could probably use a scooter and that would save him from both the descending issue and take care of his 'safety' stop too. Maybe I'm out of touch with current standards, but unless he is wearing 14mm of neoprene starting the dive off underweighted doesn't sound like a good idea (having addressed breathing/finning/etc before adding more weight).

EDIT--During a night dive (vis?? quality of buddy's lights??) a finned descent isn't a great idea. Imagine if all the divers had to fin down...you'd be lucky if two ended up in the same area. How many times do we read about divers being separated at ascent...this doesn't sound much better. If it's not a shore dive and the bottom is not visible, it is a lot safer for the divers to be able to see each other clearly and this is made easier with a horizontal descent.

 

[Crush]

When I am floating at the surface and dump all the air from my BC I still remain at the surface. When I then exhale fully and rapidly I begin to sink. At about four feet of depth I begin to breathe again, and by the time I slide past six feet my suit compression had ensured that I am negatively buoyant. All of my ascents and descents are done in horizontal trim (unless I am following a contoured bottom). In cold water, during ascent I am carrying less air (and am therefore lighter) but either my wetsuit has not rebounded fully or I keep a bit less air in my drysuit - either way, holding at 15 feet is not a problem as it requires a very small amount of air in my BC.

Personally, I do not consider myself to be properly weighted if I have to swim down.

 

[ScubaBB]

I consider myself underweighted when I barely can stay on height for safety stop. With BCD empty and full breathout you should sink, if not add weight.

 

[redacted]

Your problem is that good fitting and sealing wetsuits tend to trap some air that may take time and a bit of wiggling to expel. As long as your buoyancy is OK for the rest stop at the end of your dive, you are probably weighted correctly. So it is descent technique that needs to be looked at. I don't really see anything wrong with going head down and kicking for a bit when your weight is right. Another option is to do more fidgeting on the surface to try to expel air through the neck and arm seals. Also, make sure you are emptying your lungs as much as you can as you initially break the surface. Then try a couple smaller breaths while you are still fairly shallow to avoid halting your descent.

 

[DevonDiver]

If you've proved your buoyancy requirements (safety stop/near-empty tank/empty BCD) then adding weight isn't a solution that's going to help you. Assuming you're using the same equipment day or night, here's obviously a different reason for the inability to descend.

First off... TORCHES. Are you carrying a torch for the night dive, that you don't carry during the day? If so, is it a big floaty one? You may need to offset some extra buoyancy if it is. If the torch is negative, then disregard that factor.

Secondly...APPREHENSION. Night diving often causes more apprehension/anxiety when you first experience it. This can mean you aren't fully deflating your lungs for descent and/or are breathing deeper/more rapidly than you normally would for a day dive. That'll add buoyancy - you'd be surprised. Work your breathing and focus to empty your lungs to get your descent started.

Thirdly...KICKING / SCULLING. Most novice divers move their feet unconsciously when at the surface. This provides upwards propulsion - it feels like buoyancy, but it isn't. You may have got out of that habit for day diving, but might still do it in the night environment due to some anxiety or distraction. Cross your ankles to prevent it happening.

 

[bpotkin]

The PADI manual states that you can become disoriented if you do not descend feet first. I'm going to follow some suggestions regarding letting all of my air out and if that does not work, I'll
add a few pounds. Regarding my comments about barely being able to hold my 15 ft. safety stop, what I meant is that I am neutral at 15 ft. with no air in my BCD, at the end of my dives.
Thanks to everyone for their suggestions.

 

[clpkab]

Secondly...APPREHENSION. Night diving often causes more apprehension/anxiety when you first experience it. This can mean you aren't fully deflating your lungs for descent and/or are breathing deeper/more rapidly than you normally would for a day dive. That'll add buoyancy - you'd be surprised. Work your breathing and focus to empty your lungs to get your descent started.

+1 for apprehension having an effect

Did my first night dive in a quarry a few weeks ago. Used the same weight that I'd had for two earlier dives that day. Couldn't descend until instructor found a large rock, which I then carried throughout the dive...I don't think the primary and backup lights should have had THAT much of an effect so I chalked it up to first time jitters

 

[Mike]

I believe that I am weighted correctly being that at the end of my dive I am just barely able to hold at 15 ft. for my 3 min safety stop with no air in my bcd.

That isn't the description of being weighted correctly to me.

understand adding more weight is not the way to go.
any ideas?

Add more weight.

Why the ridiculous concern of an extra 2 lbs? Put 2 lbs on and get on with it.

A night dive I want to be heavy anyways. I'm going to be hugging the bottom, peering under everything to find the critters and being a bit too heavy is easier to deal with under the additional task loading of a night dive then being too light.

Throw on 2 lbs and go, nobody is keeping score.

 

[RIDiver60]

Adding a couple of extra pounds is probably the best advice. Something I do from time to time is: when vertical on the surface with all air out of your BC you can kick a few times to raise yourself up, stop kicking and use your downward momentum to start the decent. This will over come being slightly underweighted and allow a controlled feet first decent.

 

[K9evans]

I agree. I'm confused