Another New Diver With Some Questions!

[usmarine_7]

Hello Everyone,

Just finished up my OW cert today and had some questions. I took the elearning and did all my dives this weekend.

First day we spent the morning in the pool going over basics and then did 2 dives (one at 38ft and one at 49ft) in the afternoon going over skills and one was comfort dive where we just got our buoyancy tuned and just followed the instructor around.

Second day went did 2 more boat dives (one at 44ft and one at 60ft) there was navigation and more skills. We also did some more free diving and followed the instructor. He went over points with us the first day he wanted us to pay attention to on this dive, mine was my breathing. Guess i'm a little bit of an air hog and no one wants to dive with someone who sucks through a tank quick.

I had a few questions I didn't get to ask the instructor and figured the wealth of knowledge here I would surely find some answers.

My first question is now that i'm not going to be counting on an instructor to navigate me back to the boat what are some things that you guys do? Visibility was between 10-20ft on our dives and besides following a compass luber line for 20 kick cycles I wouldn't know how to navigate to the boat. Is there equipment besides a compas that can help?

Another question was time. I was told as a genreal rule at 1000psi and 60ft you should start your accent? Is there a rule as far as time and PSI? I know there are dive computers that can tell you that but they are expensive and as a new diver I can't afford that now.

Basically I don't want to go out on a dive and look like a moron when I can't find a line to surface on and surface 100 yards from the boat. I know I will have a buddy but I don't want to count on everyone I dive with knowing all this. Thanks in advance for all your help.

 

[Thiad]

Semper Fi. So did you pass your land nav or did you end up in the swamp like I did?? Yeah, navigation is such a joy and GPS underwater - not ready for primetime yet.

A compass is your best bet, but always look around for landmarks and other features which can help you navigate back (the sound of the boat engine is my favorite). The only way to learn is to practice and dive and navigate - as often as you can. My navigation stunk so bad that I did take the PADI Nav course and while some may buck it, heck, it helped me! After I did that (and it was a huge boost to my confidence), I made a sincere effort to lead dives and was surprised at how quickly I got locked on. Besides that, take your compass and do some land nav above water. Put a towel over your head and make patterns. Half the battle of using a compass is learning how to use it properly. As a new diver, it's difficult not to get overloaded with everything else - air, buoyancy, etc, etc, so don't beat yourself up. Small steps, get comfortable and it will all come in due time.

But even so, don't feel like you have to hit the anchor line every single time. You're not always going to and I don't think there's any shame in turtle nav especially when the vis is horrible. I've been out with divers that have far more dives than I do and sometimes, they miss the mark, too. I think the only shame is coming up on the wrong boat - 500 yards away.

Congrats on your OW.

 

[Kitty_Kat]

Congrats on the OW!

Unfortunately there is no miraculous "quick trick" to underwater navigation. The person who perfects a good (and cheap!) underwater GPS system for personal use will make a lot of money

The only way to get better at it is to practice! And that means dive dive dive! And through all of this you have to keep in mind that even after 100's of dives you still might not end up right back at the boat....

As you become familiar with dive sites, you will learn to recognize certain features that may be able to give you for info than your compass can. Sand looks amazingly similar facing north, south, east, and west that's where cues other than your compass come in!

Dont be too worried about not ending up exactly on the anchor line! My local conditions (average 10ft vis) guarantee that this is a pretty much unreasonable goal.

The first couple of times I was acting as a guide (in kelp!) I was freaking out about not getting the people exactly back to the boat. Because of this I limited the dives so we would stay close to the anchor. These were boring dives. I realized eventually that no one notices of you come up a little ways away from the boat! Get as close as you can using your compass and natural cues and enjoy your dive. It's also not the end of the world if you absolutely have to pop up, see where you are, and continue from there.

Just don't get back on the wrong boat... That's embarrassing

 

[mselenaous]

Young grasshopper, I recommend diving with more experienced divers for buddies while you gain experience and spend time fine-tuning all the new skills you just learned. Find your Yoda (dive mentors). It all gets easier with more dives under your belt. Try to dive with dive boats that put a dive guide in the water and just follow the guides until you've gained some more confidence.

As for planning your gas supply, you may have been vaguely told about rule of thirds: first third to go dive, second third to get back, last third for safety stop & emergency contingency. Your gas consumption will improve the more you dive as you get more relaxed in the water.

I recently heard another instructor give this simple version of gas planning: Your turn back pressure to start heading to the surface is your max depth with another zero at the end + 300 psi. (A bit conservative but simple for starting divers). Example: dive to 60 ft, turn at 600 psi + 300 psi = 900 psi. Dive to 100 ft, turn at 1000 psi + 300 psi = 1300.

There are more precise methods for calculating SAC (surface air consumption) & RMV (resting minute volumes) based on your previous dives gas consumption for better dive planning in the future. Here is one article on the subject: Air Consumption Rates for Scuba Diving - RMV Rates, SAC Rates, Calculations, and Formulas. There are alot of discussions on this subject here on Scubaboard.

Welcome to Scubaboard and Congrats on completing your OW cert. Dive safe, dive often!

 

[Kitty_Kat]

I recently heard another instructor give this simple version of gas planning: Your turn back pressure to start heading to the surface is your max depth with another zero at the end + 300 psi. (A bit conservative but simple for starting divers). Example: dive to 60 ft, turn at 600 psi + 300 psi = 900 psi. Dive to 100 ft, turn at 1000 psi + 300 psi = 1300.

I would clearly point out that these are supposed to be guidelines for when to surface not to turn back. Generally the turning point should be much earlier and is highly dependent on conditions (unpredictable currents, vis, likelihood of getting distracted by something cool) and how far you have I go. That's where the rule of thirds come in more.

Keep in mind that many boats will be very unhappy with you/cut off your diving if you cannot make it back with 500psi in your tank. Reasons: a little bit of insurance against unseen circumstances, SPGs are not always entirely accurate, it shows you can be responsible enough to plan a dive etc!

 

[Glenn08]

Don't rush. When you get to the bottom, stop and relax. Get your breathing under control. Then you won't go through your air so quickly. One rule of air is thirds. One third out, one third back, one third reserve.

 

[faze]

Congrats on the OW.

Firstly I'd say carry and SMB on every dive... second point I'd say carry and SMB on every dive (I'm always stunned by how many divers don't!).

The advice re diving as often as you can is absolutely sound, navigation is as much about pilot points as it is about headings.

Re Air, you'll get to understand your rule of thumb air usage as you develop as a diver - personally regardless of depth/time/etc. I always turn when either myself or my buddy hits 100 Bar (half a tank) (naturally adjusted for current, etc.) and aim to be back at the line at 50 Bar - on a shallower dive this can mean an hour under water, a deeper one, 40 mins. The Dive Plan I always run to is a maximum time and a minimum air.

 

[DevonDiver]

My first question is now that i'm not going to be counting on an instructor to navigate me back to the boat what are some things that you guys do? Visibility was between 10-20ft on our dives and besides following a compass luber line for 20 kick cycles I wouldn't know how to navigate to the boat. Is there equipment besides a compas that can help?

No other tools or gimmicks. As you develop more experience as a diver, you'll be progressively less task-loaded by the basic mechanics of diving skill. As this task loading decreases, you'll enjoy a proportional increase in your situational awareness.

Situational awareness is a key factor in navigation. You'll have more mental capacity to 'absorb' your surroundings and maintain an improved appreciation of where you are, where you came from....and where you need to go.

This, in turn, improves your ability to use natural navigation techniques. Observing changes in depth (as a mountaineer uses altitude to assist navigation), observation of underwater features, marine-life patterns, noises underwater etc etc.

Dive more... until the basic open water skills become unconscious and automatic. Open your eyes to your surroundings, develop awareness and maintain a 'big picture' in your mind of where you are.

Another question was time. I was told as a genreal rule at 1000psi and 60ft you should start your accent? Is there a rule as far as time and PSI? I know there are dive computers that can tell you that but they are expensive and as a new diver I can't afford that now.

Search the forum and web for 'Rock Bottom Gas Management'.

Some examples:

Understanding Gas Management

Return to Surface Air Volume

Rock Bottom

Scuba Gas Management

There's plenty more....

These will give you an ideal of the more precise calculations you can do to understand specific gas reserves needed for ascent (including the capacity to share-air and conduct a safety stop) from various depths. Good info..

 

[nimoh]

here is an article that IMHO is a great reference for gas planning.

NWGratefulDiver.com

I think the critical thing with gas planning is to accurately calculate the turn pressure so that you both maximize your dive time and head back with plenty of reserves.

I generally use the rule of halves for OW diving. My reserve would be enough gas for two divers to ascend safely to the surface, and I usually end up rounding this up to 500psi (in 100cuft doubles). Whatever gas I have left, I use half of it to go out, and half of it to get back. In an OOG emergency, my buddy team and I would surface where we are and not worry about getting back to the boat.

If it were critical to get back to the boat, then I would use the rule of thirds.

 

[KRL1973]

One thing not already mentioned: With boat dives it is feasable to attach a marker or strobe on the anchor line to make it easiar to spot from a distance. I have done this with my kayak and it has helped.
Check with the boat captain 1st on what they are ok with you doing in that regard.

In really bad vis reels of line can be used but you need additional training before you try that