Prior post here gave it a good concise review but no displ or ballast ratio details
www.trailersailerplace.com.au/phpBB3/viewtopic.php?f=7&t=12216This link indicated 3000kg dry weight but it is not clear if this includes the trailer............seems a lot for a 7.8m yacht...........albeit a 14hp diesel is included by the look of it.............data from these sort of listings can't always be relied upon..........
www.tradeaboat.com.au/details/2735-flinders-78-metreThis one has 8hp Yanmar...........a chunky little yacht.............
www.boatsales.com.au/boats/details/1980-flinders-7-8/SSE-AD-5424607/Perhaps you could call one or both of the above listings to get weighbridge masses? Getting the centreboard mass could be by estimation of volume of all material it is made from? It might be part timber and grp, part metal ballast encased in the grp.
For a comparison here is a Mottle 820 in trailer sailer format - which I didn't realise any were made in this format - which lists 2260kg on trailer, trailer alone 620kg. So the yacht alone 1640kg. Again these figures might not be reliable but 1640kg for a 7.8m trailer sailer seems very plausible. It is a swing keel for this 820 and assume the F7.8. Suggest check the swing keel raising / lowering complete system including securing pin etc.
boats-from-au.com/not-specified/mottle-82-metre-trailer-sailer-14184