I have a slightly different trailer to most folks (an old Santa Cruz 27 trailer) but the plastic under the keel is flat. Some photos of the setup here from during a recent repair: https://www.instagram.com/p/CJhUCZRLLAV/?igshid=la46atuld34o...

John

:: Hi,
::
:: I am going to replace the wood block that the keel rests
:: on when on the trailer.
::
:: Does yours conform to the shape of the bottom edge of
:: the keel or is it a flat block?
::
:: Mine does... but I think that is due to rot and not
:: intention.
::
:: Thanks