Trouble with passenger paddlers is as Colin says they are not the best to handle. Because they have to rely on water flow over the rudder to work, you have to go in fast, then put rudder over then go astern with power to stop them at the last minute and get your lines out smartly. They rely on springs to get alongside, I had something of a similar problem when driving Arrochar and Kinterbury, their minimum speed was 9.5 knts and max 14.5knts, because they had 4 x blade props if you stopped the engine, usually the brake shaft stopped the prop in the right position to stop water flow over the rudder, happy days.