I wonder if someone can help me figure out how much power I would need to drive my 33' longship! I calculated her dry weight at 1200 pounds so wet with 10 people on board, more like 3000. I'm leaning toward an electric inboard, finding several 4500W (6hp) brushless DC 48V motors that are reasonably priced, and think they might do the trick. 4 deep-cycle gel batteries would provide 1-2 hours' travel which is enough I think, to get out of trouble and to get around Gota Kanal. I haven't found bigger BLDC. One of the motors I'm considering goes 1500RPM, at which speed, with no transmission, theoretically moves a 12" pitch prop at 15.5 knots, more like 7 after slippage, but of course I don't know whether the motor will do that or only 4-5 knots. A Catalina 30 displaces 10,000 lb and is a much bigger hull, and someone recommended 25hp... I don't know of any longships with power on board, but if the Kraka Fyr can sail at 10 knots and row 2.5 knots with 4 oars, I'm guessing 6hp should be close for me...
We're nearing completion of planking, so might be finished by the end of the year!