Again, conventional wisdom says that a keel stepped mast is better
than a cabin stepped mast because the hole in the cabin supports the
mast somewhat.
Considering the loads and torque exerted by a sail on a mast, is this
a significant difference?
I'd think that ease of inspection for corrosion might make more
difference. I'll admit to having no experience with keel stepped
masts but I often look at them out of curiosity. Often I see the keel
step in a really moist area with lots of what looks like corrosion
round the base of the mast. Lack of access here would make me
nervous. By contrast a cabin stepped mast has a step that is easily
accessible.
For mast failures, nearly all I have heard of involve failure of the
standing rigging, common to both types of steps. However, it is far
easier to drop a cabin stepped mast to repair/inspect/replace standing
rigging than on a keel stepped mast. A travel lift can be used to
drop a cabin stepped mast but I'd think you'd need a crane too for a
keel stepped one, kinda complicated. Could this imply that keel
stepped mast rigging is replaced less often; probably not since few
people replace their rigging until it fails.
Due to lack of experience, I cannot really assess this issue.