That’s what our guide called the tandem kayaks
our tour group used to explore the ocean - 
an epithet, he explained, that comes from 
how the boats split labor between partners:

the person in the bow paddles forward
while the one at stern uses the rudder;
both can see the course ahead, but the two
must cooperate on speed and bearing. 

It’s a risk whose downside has been the end 
of many: to trust each other, and not 
resent how neither controls all progress.

Quite a trial of marriage, yet couples
go out to sea this way each summer
            returning still joined, if not also wiser.