Here are a few reasons to overhead cast with two handed rods in the surf:
1) Distance & Efficiency
Generally speaking, two handed rods matched appropriately cast greater distances compared to single handed rods.
We all experience when a blitz occurs right in front of us, the adrenaline gets to us and all the fundamentals of fly casting goes out the window. We just want to get our fly back out there in fewer cast as possible. This is where the two hander comes in with a shooting head that loads the rod quickly for an overhead cast.
2) Reaching over the waves with less effort with the longer rods.
3) Less fatigue on the body that allows you to fish longer.
4) Cut through the winder easier with the heavier shooting heads.
Rod & Line System:
For this discussion, I will focus on the rod and line system since they affect more of the casting execution.
Custom single handed rod conversions:
You can convert a single handed rod by adding a longer rear handle or a custom built two handed rod on a single handed rod blank.
1) More accuracy because of the shorter blank
2) Be able to fish closer to shore where fish may be lurking.
3) The longer rear handle will give you more leverage against the fish compared to a shorter fighting butt.
1) Shorter distance because of the shorter length of the rod.
Switch, Spey and Beach rods:
Switch rods are generally 10.5’ -12’, Spey rods are 12’+ and Beach rods are 11’-14’ based on some of the rods out there. Beach rods are made for overhead casting in the surf.
1) Cast longer distance vs the single handed conversation/custom built mention above due to length.
2) May not be as accurate as the shorter length rod because of the longer length but when you are overhead casting in the surf it not matter as much.
1) Landing the fish can be tougher with a longer rod.
2) If you are fighting a big fish like a 100LB+ tarpon, shorter rods are preferred.
Separate shooting heads and running lines:
1) Configure the system however you want, from the shooting head to the running line (fly line like running line or mono like running line).
2) If you use the mono like running line with a shooting head you can get extra distance compare to fly line running line.
1) If you use a loop to loop connection to join the shooting head and running line
a. Usually people do not fish/strip beyond the shooting head because the connection can jam up to the guides.
i. Sometimes fish are within rod lengths away and those are missed opportunities.
b. If you have a strong fish on, there are chances they can blow up the guides.
Integrated shooting heads with fly line running line:
1) No loop to loop connection to worry about.
2) Fish within rod length if not closer.
1) May not get the distance compare to a shooting head with a mono like running line.
a. From my research, I have not seen an integrated shooting head made with a mono like running line.