About the 30 liters pack ...
Yes, a fanny pack could be large enough for a day hike
(except waterwise ...) for emergency/survival supplies.
But for "normal" gear ??
Why do I also use a 30l pack for "day" hikes ?
What kind of problem do I prepare for ?
Living - and hiking - in France, I don't fear to get lost for such a long time that I will need to fish to feed myself ! No cast-away scenario here.. So no real need for a fishing kit, even if very small...
And FAK-wise, I don't plan to practice surgery on myself in the boonies ...
But what if I simply - and yes, stupidly - fall in that little brook ? I won't drown but I'll be soaked to the bones..
And if weather changes and temperature drops unexpectedly ?
Well, sure I'll be able to make a shelter, to build fire and so on ...
Or I can just take, out of that 30l pack, extra clothes and change into these, or (if not soaked) add them as extra layers..
(BTW, good list, RedFlare ..
)
What if any problem arises (let's say a wrong turn and I get lost just enough for not being able to go on before night) and the day hike becomes a "day + night" hike..?
The headlight may help, or it might be better to stay put for the night.
Then I'll be happy to have that extra water bottle under my hand : I start a "day hike" with over 4 liters of water, at least 1 liter being in a sturdy metall container. That liter is generally still untouched when I come home. It's there just in case... Just like aviation pilots are supposed to touch down at the end of their planned flight with enough gas for an extra hour.
And I will appreciate the shelter's option provided by the emergency bivvy, heatsheets blankets, poncho and so on..
So, yes, I have a mini-FAK, and a (DR's) PSK + other emergency supplies .... in case of emergency.
But I mostly prepare for "normal", everyday situations, which could occured during that day hike.
Being prepared for the unexpected, doesn't prevent to prepare for the expected (or is "expectable" more appropriate ?) !
Sure, Jim, there are a lot of things you can ditch in your list, IMHO, except if they are there so you can practise with them, in the field. But then, I would rotate gear, to test a different set each time, not take them all along.
What is really missing, again IMHO, as others have pointed, is extra clothes.
On a day hike, you will -hopefully- rarely need saline, but a woolen sweater to pull over your light Tshirt might be more usefull, more often.
Alain ______________
P.S. :
about the fall-in-the-brook scenario, if I DO drown indeed, well, I guess no amount of gear will do me anygood anyway ..