POOLSTER ex-DREG III ex-DREG III (A 919/HY 11)
Now privately-owned and somewhat altered, POOLSTER began life as a Netherlands Navy hydrographic boat, one of four DREG I - IV. Here GREG IV as built and now:
http://www.lvbhb.org/BHS/images/13507-Dreg_IV-01-fotoHistorisch.JPG
http://www.lvbhb.org/BHS/images/13507-Dreg_IV-04-fotoSchip.JPG

48t displ, 20.6 x 4.4 x 2.1 (dr 1.4)m
built 1950 De Groot & Van Vliet, Slikkerveer (Yd 271)

9/1950 Royal Netherlands Navy as DREG III (HY 11)
10/1955 deployed to Netherlands New Guinea (A 919)
1962 returned to Netherlands at Indonesian independence
1970 sold to C P Vader, Den Helder as DREG III (NLD flag, reg Den Helder) as survey boat
197x sold to Roel Donker as salvage/rescue boat
https://www.camping-kerisole.fr/wp-content/uploads/2018/02/roel12-1500x1000.jpg
198x sold to Rederij Waterweg, Workum
19xx sold to Dreg Surveying
....
by2011 owned by Ab Strijp, renmaed POOLSTER and converted to a yacht
NLD flag, reg Rotterdam, c/s PG9741, MMSI 244020033

[this history may not be exactly right - struggling a bit with translations and gaps in info]
see also http://www.shipspotting.com/gallery/photo.php?lid=2784872