Oar/paddle

Doryman's new kayak Wild Rose can be rowed.

Or paddled.

This would be a brilliant solution for this sort of problem, faced at the top of the Arun last year. I had to row up the last bit in reverse, and couldn't make the last few hundred yards at all:

The trick is to design a boat that can be propelled in either direction without looking as though it is going in reverse. I would prefer an open boat though. 

Which reminds me - I happen to have the plans for this:

Hmm...