Shore entries

[archer1960]

All my OW and AOW, and my first recreational dives were either from a boat, or a deep water pier, so I got good early at giant stride entries and then going down with the group. I know how to use my shoulder dump and/or power hose air dump, and just start drifting down vertically with no trouble.

Now I'm diving from shore, and while I can successfully get going, I feel awkward at first and it takes longer than it seems like it should to start going down. My issue is how to get the air out of my jacket-style BC when the group starts swimming in water that only waist or chest deep. Do you squeeze the air out of the BC with your arms before starting to swim? Or maybe go ahead and get horizontal and then use the dumps to unload air? Or something else?

 

[boulderjohn]

In that circumstance, I usually go horizontal and use the rear dump.

 

[Doc]

Don't squeeze the [-]Charmin[/-] errr... BC

Position one dump port "up", submerge the BC in whatever contorted position you like, pull the cord. Always let water pressure do the work of emptying the air. It's better at it than your arms.

In 3 feet of water? Just sit down. Don't worry about looking goofy, no SCUBA diver really looks like James Bond.

Examine your BC with great care and get a full understanding of exactly where these ports are, in relation to your body while your back is turned. Understand that air might be trapped elsewhere- you might have to rotate, rock and tip one way or the other to get it all.

I have seen many hundreds of divers yanking violently on dump cords but forgetting that the port selected must be at the uppermost position in the water. Simple physics, but not knowing where that port is located in reference to body position in the water column, exacerbated by stress, nothing happens. Why am I not sinking?

Remember also that the first 10 feet or so, once you push below that magic invisible line, your buoyancy will seem to go a bit more negative. This is a big obstacle in early lifetime dives- here you are at the start of a dive, the most weight you'll have thru the dive, and you can't sink. If you are indeed "properly" weighted, it can present a puzzle to most divers: (again) Why am I not sinking?

I have done many thousands of shore entries, usually with noobs or occasional divers. At my favorite Caribbean resort, CoCoView, you begin the shore dive in 4fsw and have to traverse 200 feet of shallow coral path before you hit 15' depth. A lot of butts and flippers can be seen at the surface, so I understand your issues.

It takes time to overcome the seeming contradiction.

 

[Malpaso]

What Doc said, plus one more thing. You really have to give a hard exhale to get negative at the beginning of a shore dive (remember your pool sessions?).

 

[Kharon]

What Doc said, plus one more thing. You really have to give a hard exhale to get negative at the beginning of a shore dive (remember your pool sessions?).

Seriously??? Properly weighted, every diver is negatively buoyant with a full tank and no air in the BC. Aluminum tanks (most) become positively buoyant when empty while steel tanks (most) are negative throughout. All are very negatively buoyant full. I have yet to see a tank spec that is positive when full.

If you have to do a hard exhale at the beginning of a dive or fin your way down you are underweighted - perhaps severly. You should have to do no more than exhaust air from your BC to descend. If you have to fin down and are not diving steel, negative at zero, tanks you are taking a real chance of uncontrolled ascent.

 

[archer1960]

Seriously??? Properly weighted, every diver is negatively buoyant with a full tank and no air in the BC. Aluminum tanks (most) become positively buoyant when empty while steel tanks (most) are negative throughout. All are very negatively buoyant full. I have yet to see a tank spec that is positive when full.

If you have to do a hard exhale at the beginning of a dive or fin your way down you are underweighted - perhaps severly. You should have to do no more than exhaust air from your BC to descend. If you have to fin down and are not diving steel, negative at zero, tanks you are taking a real chance of uncontrolled ascent.

That will be true once you get the trapped air out of your wetsuit, but doing that often takes a bit of time in my (admittedly limited) experience, especially with a full cold-water set.

Thanks everybody for the comments and suggestions. It sounds like I had the basic idea correct, but need to get better at execution.

 

[Malpaso]

Seriously??? Properly weighted, every diver is negatively buoyant with a full tank and no air in the BC. Aluminum tanks (most) become positively buoyant when empty while steel tanks (most) are negative throughout. All are very negatively buoyant full. I have yet to see a tank spec that is positive when full.

If you have to do a hard exhale at the beginning of a dive or fin your way down you are underweighted - perhaps severly. You should have to do no more than exhaust air from your BC to descend. If you have to fin down and are not diving steel, negative at zero, tanks you are taking a real chance of uncontrolled ascent.

Yes seriously. A full set of lungs at the surface, especially in 3-5' of water where you can't fin down, will make you float. If you sink with your lungs full, you are seriously overweighted.

 

[tursiops]

Guys, do the numbers, and keep the physics and physiology in mind. Regardless of the kind of tank, your goal is to be neutral at the end of the dive with an "empty" tank. So you need extra weight at the start of the dive to compensate for the weight of the gas in the tank. That means you'll be 4-6 pounds heavy at the surface, at the start, depending on tank size and what "empty" means to you, but NOT depending on AL or steel. So, can you fill your lungs enough at the surface at the start of the dive to support that extra 4-6 pounds? For most folks, no. Your lungs aren't big enough.

 

[Malpaso]

When we check out new divers, and we always do shore dives, invariably, the reason they can't sink is that they are inhaling instead of exhaling. That was my only point for the OP. Most of the time it is not done consciously, so I wanted to mention it to him so that he is conscious of that possibility.

 

[archer1960]

When we check out new divers, and we always do shore dives, invariably, the reason they can't sink is that they are inhaling instead of exhaling. That was my only point for the OP. Most of the time it is not done consciously, so I wanted to mention it to him so that he is conscious of that possibility.

Yup, I usually don't think of that until I have trouble getting down, then I remember that I don't need to take a deep breath like I do when I'm on a snorkel.