Trim... the old & the new

[MikeFerrara]

By "hovering" do you mean sitting still, or moving? I find it much more difficult to stay motionless and horizontal, opposed to moving and horizontal. There's some inherent tendency to go vertical (head up or head down), which is exacerbated by fiddling with equipment, and my groups "fiddle" quite a bit and are chatty. Maybe this is a weight belt and center of gravity issue... backplates may be better for horizontal trim.

Both. Being able to hover in a horizontal position does require proper balance (center of gravity vs center of buoyancy) and proper body position because those centers change with body position.

Very minor peeve.
One more thing that I cannot do when head-down, is keep my mask clear when I have a beard (I don't smear silicon grease on my face like the hardcore people). Head-up the leaking water collects under my nose and is cleared at every few exhales. Head-down the water collects by your eyes. It's a world of difference, and forces me to SHAVE in the winter months when I do solo research dives. I HATE SHAVING.

I don't have a beard but my mask leaks anyway on some dives. With a little arch in the back (not to the point of discomfort) and the shoulders rolled back (rather than hunched foreward), you can still be looking mostly foreward. Water in the mask will still be at the bottom of the mask and out of your eyes.

I also teach students to clear a mask from that position. It isn't required that you look up at the moon to clear a mask. The advantage is that they don't have to go vertical to clear.

 

[Ian Binnie]

When I dive with charters here in the Great Lakes, I usually try to be first on the wreck. This provides at least a couple of minutes of good vis before the rest of the divers (with certain saintly exceptions) kick up the bottom. Their heads up/fins down orientation almost always results in billowing clouds of silt. Overweighting aside, this orientation seems to result almost automatically from the combination of an Aluminium 80, a stab jacket, and a reasonably heavy weight belt. The stab jacket just can't compensate for the effect of gravity and the weight belt on the diver's bottom half. In contrast, using a steel (single) tank generally puts more weight over the upper torso (sometimes too much), and usually results in a heads-down orientation. I suspect that this "Aluminium 80 problem" could be easily corrected by adding a tank weight, and removing a corresponding amount of lead from the belt. The ideal tank weight might be the cylindrical portion (sawn in half) of a tank that has flunked hydro (or a Walter Kidde). Shouldn't be too hard to slip into the cam bands, between the live tank and the diver's back.

 

[MikeFerrara]

When I dive with charters here in the Great Lakes, I usually try to be first on the wreck. This provides at least a couple of minutes of good vis before the rest of the divers (with certain saintly exceptions) kick up the bottom. Their heads up/fins down orientation almost always results in billowing clouds of silt. Overweighting aside, this orientation seems to result almost automatically from the combination of an Aluminium 80, a stab jacket, and a reasonably heavy weight belt. The stab jacket just can't compensate for the effect of gravity and the weight belt on the diver's bottom half. In contrast, using a steel (single) tank generally puts more weight over the upper torso (sometimes too much), and usually results in a heads-down orientation. I suspect that this "Aluminium 80 problem" could be easily corrected by adding a tank weight, and removing a corresponding amount of lead from the belt. The ideal tank weight might be the cylindrical portion (sawn in half) of a tank that has flunked hydro (or a Walter Kidde). Shouldn't be too hard to slip into the cam bands, between the live tank and the diver's back.

You're right. When diving off those boats on a busy day you won't see the wreck unless you're the first on it.

On out last trip I had to go down to find and mark the wreck because the mooring was gone. Vis was great. After I got every one else in thawater and got back down there the wreck had disappeared into a huge billowing cloud of silt. I mean it was billowing like there was machinery churning it or like a volcano cloud. There were divers laying, sitting and standing on the wreck and the bottom. Some were trying to take pictures. Others were hovering vertical with their fins pointed at the bottom churning things up.

That was out last Great Lakes wreck dive off a recreational boat and I won't do it again.


You're correct about the tank. Aside from being overweighted, divers in heavy wet suits wearing a lot of weight often need more of it up higher. An AL tank isn't the best for this but a tank weight can help.

I'm sure AL tanks are great in the tropics but the only reason their standard around here is that they're cheap and divers don't know any better.

 

[Bmcalli]

The way I see it is that both the slightly heads up and slightly heads down positions can be beneficial. It all just depends on the plan of the dive. Foe example, If your underwater and the goal of the dive is to find the elusive frog fish, a juvenile smooth trunkfish or to break your personal record for number of pederson clearer shrimp sited in one dive then the heads down position is the way to go. And like mentioned before , I agree that its easiest to keep an eye on divers that you may be leading. On the other hand if your diving further off the bottom and hoping to catch a glimsp of a spotted eagle ray or maybe a turtle, then the heads up position allows for a greater field of view. Diving technique should be flexible for both safely and general enjoyment and I feel a good diver is one who strives to be proficient in a variety of techniques.

 

[Albion]

I also teach students to clear a mask from that position. It isn't required that you look up at the moon to clear a mask. The advantage is that they don't have to go vertical to clear.

How many new divers have i chased after having seen them sit up into a vertical position to clear their masks, not realising they have gone bouyant with this motion and are now floating up as they clear their mask.

 

[love2godeep]

From the beginning, I've always preferred a slightly head-down position.... especially since I tend to be buoyant. A modified frog-kick has also become my modus operandi.

Glad to hear that's good diving. Maybe I'll get the knack of this yet!!!!