Sailing Dingies - hillman
I was motoring through the Cotswolds in the early 1980s, in a company Cortina. You know the sort, disc brakes but no servo. The weather was too beautiful, apple blossom everywhere; quite delightful. Red light ahead, so I start to pull up behind the car in front; suddenly realise that it is towing a sailing dingy with mast horizontal and pointing my way. There was a rag tied to the tip, and it was heading for ME. Those brakes were good, provided you put sufficient boot behind them, and I did. The Cortina stopped ?on a dime?, with a great noise. It must have shaken the people in front as much as it did me.

I theorise that the subtended angle of the vehicle in front gives an indication of the distance therefrom. With the dingy being lower than the car I got quite the wrong impression.
Sailing Dingies - Cliff Pope
Quite right. I believe we judge distance by using the vertical subtended angle, not the horizontal. That is why it is so easy to walk into a washing line.
It sounds like a very dangerous way of carrying the mast. The usual way is stepped in or on the back of the dinghy, and resting on a tall Y-piece on the front of the trailer so that the mast projects upwards and over the roof of the car.