Recognition please
Looks like you have removed the two stays that ran from the platform on the mast to the deck and it looks like another stay runs from the platform to the bow. All would have been steel rope with some form of tightening device at the deck. You could use fine fishing trace but good quality scale rope would look OK. The flag bears the colours of Ukraine and is as others have said a house flag. The halyard will run to a pulley at possibly the back of the mast top and be tied off at the horizontal post on the deck. I agree with Roy that it is some form of service boat and could be Pilot, Customs or coastguard. This is supported by the number of side buffers seen. The internals suggest 1970's era build. Should last another lifetime. Be good to see some on water pics when completed.
dave976