2. When diving caves and spearing in them consider that the fish may swim around you and wind you up and fasten you to the redbait coral rock etc. - will you have enough breath top enable you to cut yourself loose and get out and back up safely??
Here for added safety you can have your buddy diver watch you or even come down 30-50 sec after you go down as a back-up - he too must have a knife.
If you need to retrieve a holed up fish rather immobilize it with a second shot before going into the cave to do the clean-up work.
You may have your mask pulled off your face while in the cave (I had that once) - now what - you ca see very badly! Perhaps you can instruct your buddy to sneak up on you and pull off your mask as some "be prepared for salty eyes" training. Just don't do that in a cave!
3. Check your weights - i.e. weight them - I have H weights that vary in weight from 1.0 to 1.3 kg - I marked them to be sure of my weighting. With 6 of these weight my belt weighed 6.8 kg. Someone not knowing better will be dragging an extra 800 grams up from the deep dives and wonder why his legs are burning.
4. Adjust buoyancy - in deep water with my now compressed 5mm suit Jacket and trousers (not a farmer john ) I prefer to reduce my weights as follows:
0-5 m - 6 weights (~7kg) Positive buoyancy from: ~3m (often dived if swell permits - anytime in dive day)
5-12m - 5 weights (~ 6kg) Positive buoyancy from: ~5m (often dived if swell permits - anytime in dive day)
12-25 - 4 weights (~ 4.5kg) Positive buoyancy from: ~8m (often dived - prefer to dive deeper earlier in dive day while strength permits)
25 -33 - 3 weights (~ 3.5kg) Positive buoyancy from: ~10m (not often dived - prefer to dive deeper earlier in dive day while strength permits)
33 - down 3 weights (~ 3kg) Positive buoyancy from: ~15m (rarely dived - must dive early in dive day while strength permits)
Use a quick release belat that can be discarded easily. Practise discarding it too.
5. Check your neutral buoyancy point (depth) as it will become shallower as your suit compresses. Deep diving compresses your suit much faster. When buying a suit - if it is very light and supple it will probably compress fast.
To check it you must go down and find from what depth you float up on a full breath - you will need a calibrated rope or depth gauge.
6. Don't hyperventilate (i.e. huff and puff like a steam train - slow deep breathing will be best. If you vent out all you CO2 your trigger to get back up (i.e. your urge to breath) is delayed and you may black out. See link below for more data (http://en.wikipedia.org/wiki/Shallow_water_blackout)
7. When trying new activites your chances of making a blunder are far greater as you are still learning. The only samba I ever had in the sea was when i was in my second year of diving and I sat on the seafloor waiting for a red stumpnose to come in close - at about 34 m i dawdles and the a bankie swam in so I shot it and it went into a hole - I began pulling. (I had no urge to breathe as the pressure made by blood fill with oxygen). Luckily I took off my weight belt clipped it to my float line and headed back up where I entertained the others on the boat with a samba. Let's say i had a reel gun and feared the loss of my belt and tried to get back up - I doubt I would have made it. I was new to deep diving and could easily had black out that day. No one was in with me!!!!
If I had a buddy diver watching me - i.e. coming down to meet me on my way back up - say he met me at 15 m he could have taken me back up even if I had blacked out at 10 m.
8. Use a depth gauge -especially in clean water where reef structure is jagged and you can got deeper than expected. Often one can set alarms for various depths.
9. Let go of your gun and that prize fish if you get a reeljam, or the line fouls on your rubbers. Rather lose the gun and the fish than take a big risk saving your gun. Same applies to dumping you belt if you must - let it go. Take a spare belt and gun with one boat dives so that if you have to discard one then you have a spare.
10. Avoid competing against good divers on the same boat when you are inexperienced - this has been the cause of many a blackout.
11. Some divers exhale before diving so as to be less buoyant and sneak down on the fish - this is probably a new activity for many a diver and realize that you are less buoyant and have less oxygen to use. A big fish can easily lure your down and if you give chase with less oxygen and reduced buoyancy it becomes a super high risk activity.
12. Medication - some drugs trash your breathhold ability. Chat to your doctor/pharmacist - they may be able to help but quite possibly they do not know how the drug will affect your freedive ability. When on medication take it easy (shallow and short dives) - or don't dive at all.
Note:Ginseng and chromium combos in weight loss tablets and multi-vitamins tend to reduce my breathhold.
13. Hydrate - have a good supply of water / cold drink and take regular doses to rehydrate. Take some food along too - fruit can be good with potassium and sugars.
14. Train on land to add strength for your sea outing - it can help a lot.
Well there is a list of safety tips that can help you dive more safely - how do you fare against that list?