The first Dutch motor barges where sailing barges, Tjalk,Klipper(aak) Stijlsteven to name just a few, that they motorised, after a start with motorising their rowboats, that were used as pushers, or an engine on the front deck, that was driving a propellorshaft, hanging over the side, that had a clutch, and only forward and neutral. In the beginning they kept their sails, but reduced those more and more, until they were familiar with their engines. Space wise, on sailing barges of the same size as motor barges the useful space inside should not be different. If an apperently accomplished sailor wouldn't take one to sea, because they don't sail well, he should go to Holland a couple of times, to enjoy the sight of those barges racing, and he will change his mind about them. this man is most likely a sailor that only sailed yachts, and has never been on a sailing barge. I used to own a bigger version of a Tjalk, built in 1897 that was used for the Baltic trade, when times were hard, they were called "Oostzee Tjalk", and if a barge of that age survived under those rough conditions, that proves that they were more then capable of "coastal" sailing. By the way, this old barge that once was mine, is still going strong, and is now trading as hotel-motorbarge, around Venice (Italy).