The UT706 was a poor relation to the UT705, designed, one assumes, to save a bit of money in construction. But of course it still required, and requires, the same number of crew. If it has an advantage it is powered with the same 6000 bhp Bergen diesels, and had two tunnel thrusters forward and two aft, therefore making it fractionally more manoeuvrable than the larger vessel.
The main illustration is of the Oil Tracer taken by Tony Poll out in Brazil. This ship was built in 1986 originally as the British Viking.