keel bolts are typically installed in pairs, so I'd try to determine if the crack lines up with a bolts head
as seen from the inside....
you could take a level and try to run a vertical marked line from the crack up the hull
to give you a reference point.
if the crack does indeed line up with a bolt head
, my guess is that it is a keel bolt that was installed a bit to close the outside of the keel.
The material of keel boat varies...with stainless steel
the most common
I've added a short explanation for you :
: The most common keel-bolt material in America is stainless steel
. This is dismaying to many, because stainless steel
suffers rampant corrosion
when immersed in stagnant seawater. Using it for keel bolts anticipates that the bolts will remain dry—which is optimism bordering on delusion.
Stainless steel comes in various varieties....type 316 is the most well known to sailors as rigging
wire is made from this...316 is not the strongest, but is the most corrosion
resistant......the keel bolt is likely a type that is not 316...
If the crack lines up with a keel bolt head, I would say you've found the source of the problem. Unlike steel, which rusts, stainless steel corrodes...