How to best tow and inflatable dinghy behind a sailboat / yacht?

Towing bridle is necessary in order to properly tow your inflatable boat. Towing bridles are available at many marine retail stores and on-line. Do not tow the inflatable boat by connecting rope to the central D-ring with integrated handle. Use towing D-rings on both sides of the dinghy bow.

The most common mistake made when towing is the improper use of the towing bridle. Many boaters knot the tow bridle into a loop at the center, and attach a towing line there. This is wrong. The towing line should not be fixed to the bridle, but instead should end in a small bowline loop, through which the bridle passes. This allows the towline to slew back and forth in the bridle, and provides for tension on both sides of the bridle. Not rigging the towline this way is the most common cause of failure of the pad eyes on the dingy to which the tow bridle is attached. It is inevitable that during towing, the dingy will rock a little from side to side, shifting the strain on the bridle from one side to the other. If the towline is rigidly fixed to the center of the bridle, one pad eye will be momentarily required to sustain the entire tow load. If the towline can shift its position in the bridle, both sides of the bridle will remain in tension, and the load will be distributed to both pad eyes on the dingy. 

Many cruising sailors have small outboard motors for use with their inflatables, which creates a dilemma when it's time to tow: should the motor be left on the dingy while towing? The tendency to do this is proportional to the weight of the outboard and the difficulty in removing it and storing it on the boat. There are a number of reasons for recommending against towing with the outboard on the dingy.

First, there is the hazard to the outboard. In large seas the dingy might flip over, submerging the motor. It's also possible that violent motion in the seaway could cause the motor to fall off the dingy transom. These things always seem to happen when you'd least expect them to, usually when a ten-foot sea is running!

Another consideration is the additional tow load the extra weight of the motor will create. A completely empty inflatable is usually a very light craft and hence a very light tow load. When you add 40kgs or more of motor and gas tank, you could very well be doubling the tow load from a small inflatable.