JKA
Paddler
Rather than hijack this thread:
www.westcoastpaddler.com
I thought I'd ask the larger team.
How? Anyone? Photos?
While I can think of a few ways to do it there may well be more thought-out systems already being used. If so, I'm keen for details.
Seaward says this:
paddlingmag.com
Sensitive West Coast company Seaward anticipated the “divorce boat” potential of tandems and offers an optional dual-steering system that allows control from either cockpit ($224 CAD).

SOLD! - Seaward Passat G3 Fibreglass Double Kayak $2700
This beauty is ready for a new home as it is seldom used. Originally from the Yukon, she has paddled in the famed Yukon River Quest paddling race 3 times with strong finishes. She has also spent time exploring Yukon's lakes. Since moving to Vancouver Island 5 years ago, she has yet to dip her...

I thought I'd ask the larger team.
On-the-fly rudder control switch from rear to front cockpit.
How? Anyone? Photos?
While I can think of a few ways to do it there may well be more thought-out systems already being used. If so, I'm keen for details.
Seaward says this:

Boat Review: Seaward Passat G3 Kayak
In the name of Seaward Kayaks’ newest tandem, the Passat G3, you can hear echoes of two other brands, Volkswagen and Apple—two hip, sophisticated

Sensitive West Coast company Seaward anticipated the “divorce boat” potential of tandems and offers an optional dual-steering system that allows control from either cockpit ($224 CAD).