tow dingy with outboard?
DON''T RISK THAT EXPENSIVE ENGINE!
I have towed both inflatables and hard dinghys. I have a 32 foot ketch so removing a 15HP engine was never a problem .. the mizzen boom was used to transfer the engine.
I had an inflatable flip over between Oahu and Maui, Hawaii. After bringing it alongside it was VERY difficult to lift it up since a vacuum had been created inside while towing it upside down. I pushed the drain plug in and it popped up out of the water! I then learned to tow it very close to the transom on the lee side when going upwind (where it never flipped) and to let it out to the first major wave behind when off the wind. It sometimes tried to outrun me going down wave and wind but that could be correctecd by adjusting the length of the towing line. I found the reduction of boat speed as others have said .. up to 1/2 knot.
I now have a hard dinghy which I tow and have had it in 25 kt wind/12 ft seas on a beam reach and it rode nicely back there. I have also gone to a smaller engine (3HP Yamaha) which is easy to transfer without the boom. My boat speed is reduced less than 1/2 knot which is acceptable for short passages.
For extended passages I bring the dink aboard (it''s a nesting one) then it doesn''t interfere with the towing generator, I gain the extra speed and lose concern of what''s happening to it, especially at night.