For a beginner, the weights should be last on. Most divers, as they
become experienced and comfortable, switch to weights first (in my case,
in winter configuration, under a crotch strap) because the risk of
accidental loss of weights outweighs the desire to easily dump weights
in a panic. I have my weights in summer configuration permanently on the
harness straps.

esg

Indeed.

Same here.

Then don't do it that way, and don't let your dive leader try to
intimidate you into changing.

The bottom line for the entire weightbelt issue is very simple:   what
trade-off decision do you wish to make in regards to ditchable
weight?

In the old old days, there was very little concern about avoiding a
too-fast ascent from an accidental loss of weighting while at depth.
As such, the priority was the ability to ditch weight, and a suiting-
up procedure that specifically avoided the accidental entrapment of
the weightbelt.   Since early BCs were horsecollars with a waist and
crotch strap, there was a very real risk of the BC's straps trapping
the weightbelt to prevent a ditch, so the rule was 'weights last'.

Fast forward to today, where the common BC equipment is a jacket style
with cummerbund ... and no crotch strap ... the risk of weightbelt
interaction is very much reduced.  As such, one sees it as low risk
and generally more convenient to put the weightbelt on much earlier
while on a hard boat, followed by the rest of the gear.

And this preference-for-convenience is then exasperated on "Valet
Service" types of dive operations, as they'll have you put yourself on
the boat transom with weights, fins, mask and the staff hauls your BC/
Reg/Tank combo from the rack to you.

Finally, frequently for drysuit divers and/or technical divers where a
rapid ascent is more undesirable, the risk management preference is to
make the weightbelt into (less, or) un-ditchable, so as to prevent its
accidental loss.  One may also find double-buckle weightbelt systems
for the same basic reason.

Overall, there is no single simple answer except that the
identification of, and the subsequent management of, the amount and
location of  ditchable weight is a configuration consideration for all
good divers that needs to be holistically considered in full context
of the risk-benefit trade-offs.

-hh

"Hoges in WA" <tzhoganzz2@bigpond.net.au> pounded away at his keyboard
resulting in:

You may have been wearing a horse collar style bc with a crotch strap.
The weight belt would go on last so it went over the crotch strap, not
under.  You have to be able to ditch it.

Putting the weight belt on before the bc enables you to cinch it
tighter, making it less likely to get out of position.

Dan Bracuk
Never use a big word when a diminutive one will do.

<snip>

Likewise, in 1972.  But as others have observed many horse collar BCs
had crotch straps then.

I gear up in the order I gear up and try hard not to vary my routine.  I
certainly would not change it based on what some random DM on a dive
boat said.  (I'd probably thank him and put down any piece of gear on a
nearby bench unless I was ready for it.)

In all cases, though, I put the weight belt on before the BC/tank or the
backplate/wing/tanks.  With the BC, the tank extends past my waist and
it's easier for me to put the belt on first, and much easier to get it
correctly positioned and snug.  With the BP/wing the belt goes under the
crotch strap on purpose for the reasons others have stated, *and* it's
easier to put the belt on first.

The vast majority of my diving is in cold water.  I split weights
between a belt and my BCs (which have integrated weights).  If I have to
ditch either one alone I don't want to be too buoyant.  With the BCs I
have there are no crotch straps so ditching the belt is easy enough no
matter whether it goes on first or last.

With the BP/wing and doubles, I have a stainless steel backplate (which
splits the weight the BP and the belt) and full redundancy (including a
double-bladder wing in addition to a dry suit for buoyancy) so the risk
of accidentally losing the belt seems far greater to me than that of
having to unclip another strap first if I have to ditch it.

On most boats, I put on underwear, suit, knife, computers, fins, belt,
BP/wing or BC, reel, primary light (this will change this year, since I
made a canister light), hood, gloves, and mask in that order.  Other
gear is already on the harness or in the suit pocket when I start to
dress.  Some of these things obviously must be done in order, while the
order of others could be varied.

Comfort is a big part of things and you should be comfortable and
confident that the procedures you choose will safely work for you.

Even stranger was getting back into a boat while still in the water, the
dive leader told me take BC off first, then weights. Huh?