Light but durable fly rod carrier?

Fluorescent bulb protectors? Rubber end caps. Home Depot.

Very cheap and durable would be ABS plastic of the appropriate diameter and length. But that's not very UL.

I snagged some plotter-paper rolls (like the cardboard tube inside a paper-towel roll, except it's plastic, stiffer, waterproof, longer and wider). 2" I.D. 36" long. 180 grams. So 27/36*180 grams = 135 grams / 4.5 oz in your length. I'd glue a test plug (translucent plastic disks with an indent sold in the ABS fitting section to be glued onto rough plumbing to accommodate a leak test and then be cut off) on one end. For the other, operable end; I'd use one of those flexible plastic caps found on a 6-inch-long tube marketed for storing screws/nails in.

PM me if that is of interest. If your garage doesn't have a zillion glues, epoxies, etc like mine, I could cut it to length and glue it up for you.

I use the lightweight fluorescent bulb protector tube from Home Depot but I keep it tucked away inside my pack to give it a bit more protection while on the trail. I'm not sure it would give enough protection if it was only strapped to the outside of a pack. At least I wouldn't want to use it that way to carry and protect my $700 Winston fly rod.

I bought 2" diameter clear plastic tubes from US Plastics. They have a lot of different thicknesses. I made a tube for my 8' bamboo 3wt. It weighs 4oz with the end caps.

"… the lightweight fluorescent bulb protector tube from Home Depot "

+2

Add the plastic caps used on chair legs and you are set. I carry on the outside, bash and thrash, and do just fine. After all, they are made to protect fluorescent tubes from errant impacts.

I don't carry my super expensive gear when I backpack, but I obviously still want my gear to arrive in good working order. I carry my rods wrapped in a tube of my 1/8 foam pad that I use as protection for my inflatable pad. This is mounted on the side of my pack with the reel end going in the cup holder/ski pockets on the bottom of the pack and the compression straps keeping it upright. The reason why I like this system over tubes which are probably a bit more protective is that the rods (2-3 because I'm crazy)are all rigged up with the reels on the rods and line through the guides ready to be used. Each rod combo (spinner in 2 sections and fly rods have 4 sections) are velroed together with two hardware store velcro straps to keep things neat. Then, as soon as I see a spot that I want to fish I just pull out one of my pre-rigged combos take the velcro off and put the lure/fly on from my hip belt pocket and then I'm fishing within 2-3 minutes. Then, when I'm finished I just take of the hook and slide the combo make into the foam "tube". The foam stays rolled either with velcro strips that I attach or you can use stretchy cord.

This way, the way I justify to my self for bringing the 2nd or 3rd rod, because I don't actually carry the extra weight for a rod tube because my pad "needs" protection :)