Indeed they were piston engined ones, powered by two Lycoming IGSO-540-A1E engines with 385 hp each.
The Do-28 G.92 turboprop version used for skydivers is using two Walter Engines M601-D2 with 450 hp each. Not too much of a difference but turboprops have vastly different performance characteristics which makes it much more "sporty" than the piston engine ones.
Two of the Do-28 were upgraded to Do-28 OU oil pollution control aircraft, putting in as many sensor equipment as it could take.
Our Do's were disbanded in september 1994.
Another navy squadron took over both oil pollution control and transport roles with newer Do-228 (and Do-228 LM for oil pollution control) turboprops (I flew with them a few times, no comparison to the old Do-28).
At least the oil pollution control was a true success story. Within the years 1986 through 2002 those aircrafts operated 18.000 hours of flight where they could track 2.900 pollution incidents of which 300 polluters could be identified.
You can read a short story about our Do's here:
http://www.fly-navy.de/props/do28.htmlImages... The "standard" Do-28D2 used for transport missions:
![](http://www.flugzeuginfo.net/acimages/do28d2_kp.jpg)
And the Do-28 OU used for oil pollution control:
![](http://upload.wikimedia.org/wikipedia/commons/4/47/Dornier_do_28_d2_sky_02.jpg)
Best regards - Mike