Tony M May 21, 2012:

2-sets I am a little worried here about the way this is written; normally, we'd just write "2 sets of..." — the addition of the hyphen seems odd. It could, of course, just be the fact that the writer was not very literate; but then they used the hyphen correctly in 'single-step'. So there just might be more to this than meets the eye...

I'm wondering if this means in fact 'a set of 2' — I could imagine that you might have pairs of single-step locks, not contiguous so they would form a single 2-step lock, but two single-step locks spaced apart.

Before coming to any hasty conclusions here, I would strongly advise doing some research into the actual canal system being described, to check just what is involved, exactly.

GGruia May 21, 2012:

Sorry! I made a mistake translating into Spanish.