Question Backup lights

[stuartv]

Thanks for the videos. The latter does look brighter to me. Often I find figures brightness/power level confusing, and not necessarily as expected as it claims.

It is important to understand a few things:

- Many manufacturers state a lumen output that is, well, falsely inflated.

- Lumen output is the total output. If two lights have the same lumen output, but one has a wider beam than the other, then one will illuminate a small area more brightly, and the other will illuminate a bigger area but not as brightly.

- a narrower beam will make it easier to see something far away, if the water has any significant amount of particulate in it. A wider beam will light up the particulate in front of your face. The glare from that makes it harder to see. In gin clear water, a wider beam obviously lights up more of your target.

- Candela or candlepower is a different way of measuring light. In simple terms (for ease of understanding), it is the number of lumens per square inch on the target. So, our two identical lights, except for beam angle, will put out the same number of lumens. But, the wider beam will be a lower candela because the lumens are spread over a larger area. The narrower beam will be a higher candela. Even though they are both putting out the same total amount of light (lumens). Most manufacturers tell you lumens output and beam angle. Some choose to give candela in their specs. Those seem to often not give lumens or beam angle. That makes it hard to compare lights.


In the end, I think manufacturer's false claims of lumens output is the biggest contributor to "brightness" being "not necessarily as expected".

And, not understanding how lumens output and beam angle work together to produce a certain brightness (aka candela) is the second biggest contributor to that confusion. A 2000 lumen output in a 90 degree beam will NOT appear as bright as a 1000 lumen output in a 6 degree beam.

Apologies if that was just stating a bunch of stuff you already knew.

 

[Learner Diver]

Manatee is a cave diver.
In the caves there are no other light than what you bring inside.
Backup light comes on if the primary light fails - thus that backup light will be used until one is out of the cave - where the dive is finished.
Same applies inside a wreck, light will be on until dive is over/ one does deco stops in open water and have "all of the time in the world" to fiddle with the light.

Hence - turning off the light is not a consideration.

That’s useful info to know he’s an experienced cave diver. Someone I can cross reference ideas. Once I’m fully certified I want to experience a night dive, and eventually buy 2 simple flashlights on eBay which are reliable, easy to operate and maintain. My 12 month goal is to take part in a full cave course with IANTD somewhere in Florida. For the foreseeable future I’m looking at doing swim throughs like the ones I see on YouTube, just to see if I can remain neutrally buoyant. So knowing if a rear button or twist lock flashlight suits my purpose is being studious on my part. Let’s face it, no novice diver wants to find themselves in total darkness on their first night dive. It can lead to utter panic.

 

[steinbil]

My 12 month goal is to take part in a full cave course with IANTD somewhere in Florida.

Respectfully, you're getting way ahead of yourself, and I don't think the timed goal is going to help you. Sure, as a long term goal it's great, but if you start rushing through classes to get there, I think you're doing yourself a disservice. This is what's known in the industry as "zero to hero".

Even if you are exceptionally talented, dive 3+ times per week, have mentors to guide you and you excel with challenges I think there is something to be said for the passing of time as part of gaining experience, and 12 months seems like a very short time frame.

I'm not cave trained, but I recently finished introductory technical training after 2 and 1/2 years of diving and 100+ dives, and I was worried that I was progressing too fast. I plan to start introductory cave training next year, after 3 1/2 years, but I have no rush to get to the full cave level.

I am of the opinion that for every level you train, you should get substantial and varied experience before moving on to the next level. Optimally I'd say in the ballpark of 1 year + 40-50 dives before progressing. Take one step at a time, gain experience, get evaluated by some one else and see when it makes sense to progress. If you said that you hoped to start intro to cave in 2 years, I'd say "good luck" and maybe you'd get there. Full cave in 1 year is crazy, in my opinion.

I would say the same to someone newly certified, but you don't even know how the OW class is going to be for you. I wish you the best of luck, but try not to rush, don't focus on the end goal, enjoy the process and enjoy diving to gain experience.

 

[grantmac]

If total darkness under water is going to cause panic then night, wreck or cave diving isn't for you.

 

[stuartv]

That’s useful info to know he’s an experienced cave diver. Someone I can cross reference ideas. Once I’m fully certified I want to experience a night dive, and eventually buy 2 simple flashlights on eBay which are reliable, easy to operate and maintain. My 12 month goal is to take part in a full cave course with IANTD somewhere in Florida. For the foreseeable future I’m looking at doing swim throughs like the ones I see on YouTube, just to see if I can remain neutrally buoyant. So knowing if a rear button or twist lock flashlight suits my purpose is being studious on my part. Let’s face it, no novice diver wants to find themselves in total darkness on their first night dive. It can lead to utter panic.

"A goal is a dream with a deadline." - Napoleon Hill

Props to you for looking ahead and setting goals for yourself. There is absolutely nothing wrong with that. To the contrary. You might not hit your deadline, but you almost certainly won't fulfill your dream if you don't set yourself a deadline to work towards.

Many in this community will judge a timeline too aggressive and proceed to assume you are going to take shortcuts to meet your own deadline. Maybe that is how they operate. It is not how I operate, and I lean towards giving you and others the benefit of the doubt and presume you/they don't intend to take shortcuts either.

I set myself goals of a similar nature throughout my progression from OW to cave diver and technical instructor. The key is to learn what is required to achieve the goal the right way, follow through with that, and be flexible in your plans as your progress and learn more. Dreams change. Deadlines change. That's life.

I think a 12 month goal from OW to full cave is very achievable. But, it will require a lot of work, a lot of time in the water, and a lot of self-discipline to spend your time in the water wisely. (And a lot of money) Many couldn't do it themselves and will tell you that you cannot do it, either. Don't be discouraged. And don't be pig-headed if and when circumstances evolve and your dreams change or your deadlines for yourself need to be pushed back.

When I finished my first tech training (Advanced Nitrox & Deco Procedures), I had a goal of doing TDI Trimix 1 year later, and Advanced Trimix 1 year after that. I think they were good goals. But, life happened and I was not able to meet those original deadlines. So be it. I moved my goalposts and kept working. What I did NOT do was sign up for Trimix 1 year later despite not having done what I needed to do in the meantime in order to be properly prepared.

Setting oneself a deadline does not automatically mean that you'll "cheat yourself" in order to meet the deadline. You might be tempted at some point to take a shortcut. If you're the type of person that gives in to that kind of temptation.... technical diving and especially cave diving is not for you. "Do it the right way or don't do it at all" is never more true than when you're talking about technical and cave diving.

Moving on....

You don't need to go into an overhead environment to see if you can remain neutrally buoyant. Practicing in a shallow pool will do far more to tell you that than swimming through a short tunnel at depth.

Performing all the basic skills while hovering in good trim in 4' of water, without touching the bottom or breaking the surface, is a much better test of your buoyancy than swim-throughs.

Cave diving will require a significant investment in money (as well as time). Night dives require you to have two lights. Get a DGX 700 and a DGX 1000-6 to start. One is twist and one is push button. They use the same battery, and they are great quality and very inexpensive. Use them both and decide what you like after getting some experience. The cost of the two lights is but a teardrop in the ocean compared to what cave training and cave diving will require. And you need two lights anyway, in the meantime...

 

[flymolo]

get 2 halcyon scouts or 2 light monkey 3w led backups. simple twist on/off, no buttons to break or press against your harness and turn on. both powered by 3 c-cell batteries that are easy to find wherever you go. i replace the batteries in mine once a year or if i've used the light for any extended period of time. burn time on the light monkey 3w backup is 600 minutes

 

[Simpel]

I like the Tillytec Mini Uni S3
4 hours runtime with 21700

 

[stuartv]

I like the Tillytec Mini Uni S3
4 hours runtime with 21700

You can get 10 hours out of a DGX 1000-6 (also uses 1 x 21700) - on Low.

Almost 3 hours on 1/2 power (which is still brighter than most).

And all with constant output.

The TT Mini S3 with the 1400-30000-5 module claims 1400 lumens output, for 4 - 6 hours.

I don't actually believe it's possible for a 21700 battery to power 1400 lumens of output for 4 hours. Not with today's battery and LED emitter tech.

If it really does give useable light for 4 hours, my SPECULATION is that it is producing less than half that many lumens for most of that time.

 

[Learner Diver]

set myself goals of a similar nature throughout my progression from OW to cave diver and technical instructor. The key is to learn what is required to achieve the goal the right way, follow through with that, and be flexible in your plans as your progress and learn more. Dreams change. Deadlines change. That's life.

Bless you for those kind words and support in my endeavour to satisfy my adventurous spirit. Several years earlier I was involved in a horrendous motorcycle accident which resulted in a fatality. My motorcycle was wedged inside the door of a mini clubman driven by a judge. When I awoke from a 3 day comma, I was being finger printed by detectives from the special branch. I still have no memory of that awful event. The detectives were mystified as to why I was alive and without a scratch on me; although, my helmet and leathers were a mess. They found me 100 yards up the road lying in a ditch. A week later they returned to say investigations had cleared me of any wrongdoing, and the judge was a little tipsy. It took 6 months of rehab before I could walk and talk coherently with the help of a wonderful and caring medical team. That’s in the past and I’m looking forward here on.

 

[stuartv]

Bless you for those kind words and support in my endeavour to satisfy my adventurous spirit. Several years earlier I was involved in a horrendous motorcycle accident which resulted in a fatality. My motorcycle was wedged inside the door of a mini clubman driven by a judge. When I awoke from a 3 day comma, I was being finger printed by detectives from the special branch. I still have no memory of that awful event. The detectives were mystified as to why I was alive and without a scratch on me; although, my helmet and leathers were a mess. They found me 100 yards up the road lying in a ditch. A week later they returned to say investigations had cleared me of any wrongdoing, and the judge was a little tipsy. It took 6 months of rehab before I could walk and talk coherently with the help of a wonderful and caring medical team. That’s in the past and I’m looking forward here on.

Years back, I was in a not-as-bad-as-yours-but-still-pretty-horrific motorcycle accident while racing at Barber Motorsports Park. It only thanks to the luck and skill of the surgeons at UAB Trauma Center that my leg was not amputated. All my other broken bones and punctured lung were ... less traumatic than my leg.

We count our blessings and move on.

Good luck to you!