I had a chat with Giacomo De Mola after the Euroafrican and we spoke about variable weight in spearfishing… he came up with some interesting considerations and tips that may be interesting.
I have also spoken with other friends that use VW (not the car…) regularly and i can summarize a few points:
1) there is a trend between the spearos in downplaying the possibility offered by this method, too often connected with deeper dives.
2) why VW? To increase safety and comfort at normal quotas or to reach quotas otherwise unreachable for you? This is the pivoting point and question that everyone has to answer before trying VW
3) pendulum or 2nd belt? I don’t need nor want to fish at depth that I wouldn’t reach in constant weight, so the pendulum is a bit of an excessive solution… I’ll go for 2nd belt (can frenzel… no handsfree required).
4) the acquisition of the correct techniques for a proper compensation of eardrums is given as granted for spearos that want to VW… if in doubt it is better concentrate on the basics before going for VW
The 2nd belt method is easy and intuitive:
– first wear a belt with the minimum weight you’ll need at the quota you want to fish at and right for you wetsuit thickness (trial and error… start with less and add weight step by step)
– second, prepare a belt with just 1-2 kg extra than what you’ll need for the same dive in constant weight … don’t exaggerate because it may be bad for you ears! This belt has a D-ring where you attach your buoy line that, in this case, will be a rope thick enough to be comfortably recovered with gloves (is not an issue of strength but comfort… so 1.5mm dyneema is out of question)
The rest is easy… you dive regularly and compensate regularly… when you reach the gliding quota you simply drop the second belt and carry on with your dive.
Soms guys use a rope 5-7m shorter than the bottom (caduta) while others prefer to reach the bottom and then drop the belt to proceed in agguato or aspetto… you pick. Personally I think that the current conditions may choose for you: if the buoy is firmly anchored to the bottom and you resurface 30-40 meters downstream, you risk not to be able to recover it… also because you’ll float like a cork.
Tomorrow I’ll be in italy and check out about quick lead options for easy setup of the weight… better to ask to the guys who already use it that to go guessing.
On Facebook you can find the page of “Giacomo De Mola athlete” and there he just posted a picture of the dive profiles VW-CW at similar depths (2.5 minutes at -38m for him but it gives the idea of the difference)… I’m on a plane right now so I cannot post the picture so… DIY