UKC

If you’re climbing a long multipitch route with small backpack on and the route goes through a tight space, what’s the usual technique for getting through it with the least bother?

Do people just hang the pack from their harness using a sling or similar?

Usual tactics...

1. Don't take a sack if you can

2. If you must... then ask your second to carry it

I almost wrote “seconding” instead of “climbing” but optimistically hoped it wasn’t necessary 😂 

Occasionally use one of the two ropes (pulled up through the gear first & tossed back down) to haul up the bag(s) before second climbs, or whilst the second climbs if they get caught up along the way. May necessitate a shortened pitch/extra stance to avoid too much snagged baggage 

Similar. Sometimes best if second pushes sack ahead of them attached to self by sling or to appropriate second rope or even clipped to a single rope ahead of them, as appropriate. Leader can leave his sack clipped to protection for second to manage if found necessary during the pitch.

I feel qualified to answer this having climbed Lockwood's Chimney with 3 mates and 4 large packs on a day that was too crap to do anything sensible.

The answer is climb as 2 pairs. The first second and second leader get the bags and have all the fun. First to have a sense of humour failure buys the beers.

I'm baffled. Why on earth didn't you leave the packs at the base of Lockwoods? You have to go back there anyway....

You said "small pack," right?  Set it up with a sling running from the hauling points to your harness belay loop.  When a constriction looms, doff the pack and drop it.  You want the sling to be long enough so that the pack hangs just below foot level and so does not mess with your footwork. With the constriction vanquished, pull the pack up and put it on (of course you need a stance or an anchor or both for that).

Quick and dirty (read tedious and inconvenient), take it off and dangle it from harness.

Or depending on your ropes, consider using one rope as a haul line if not already in any protection.

Or take it off at the constriction, fix it to some pro and let a second send it up on one of their ropes.

Ideally you would want to see the constriction coming and haul both the leader and seconds pack after leading the pitch. If it gets snagged, second retrieves it on the way.