Originally Posted by TitoSoto
Can you fully replace a keel with a beamier design (or vice versa), or is there always a balance to be struck between beam and keel depth
In the most simple terms, anyone can do anything; how well it works is another matter.
Ballast (as often found in keels) provides righting moment.
A wide beam provides form stability.
Both help to keep the boat upright, but there are significant differences.
Without ballast, a design providing high form stability (think catamaran) tends to sail quite flat, but is just as happy upside down as it is right side up.
Whereas, without form stability (think narrow beam monohull), a heavy ballast design will initially heel very easily and then stiffen up rapidly.
If the design parameters specify a self-righting vessel, yes, there is a balance between form stability and ballast.
If the design parameters do not specify a self-righting vessel, then ballast can be foregone for form stability.