John Fereira wrote:

The Lightning Std. also has a flat blade and is much more affordable than
Nigels Paddles. Up until a few months ago when I bought a Werner Cyprus
I used one for many years and loved it especially for ruddering strokes and
sculling.

I think Lightning went out of business, but the NRS catalog or website
(nrsweb.com) offers some flat-bladed paddles oriented towards beginners,
including Ainsworth.