Ben at the Invisible Workshop has put pictures up of the Galician one-handed rowing technique. The oars have a square section at the thole pins so they cannot deviate from the vertical, which makes it possible to pull the oars with one hand wrapped around where they cross. Having to slide your hand up the oars must limit the power you can apply, but it would release one hand to cast a line with a lure.
The construction of the oars is interesting too, with two halves lashed together. Cheap to make, I imagine, but weaker and heavier than a pair of Collar's Macons.
Note the anchor at the bow - Ben has a very nice pic of it. I want one for use in the harbour and another for my mantlepiece.