yes they can be,if not proportioned correctly.
the one in question looked odd to me when I opened the box,my first thought was that it would not perform right but,then I said I don't know much about building one so,maybe I could be wrong.
seems I was dead on.
the wood darters need to have a head that's wide enough to grab the water or they will not dart.
the one in question does not.
I built these to dig deep when the fish are holding down low.
esp for 3 spots I know of where one can fish on a low bridge,they dig down perfectly.
let them ride the tide waay out then slow roll them home or half way then repeat.
has worked great for me using the creek chubb giant pikies and rebel's large sliver.