OX66 225 split water supply tube

[kingfish]

In a separate thread ("OX66 225 low speed overheat") I posted about our 5 year odyssey tracking down a low speed overheat problem that culminated a couple weeks ago with the discovery of a split in the water supply tube (between the exhaust manifold and the bottom of the power head).

My question, aimed particularly to Boats.net. is, has anyone ever seen this before, and what is/are the cause(s)?

Thanks in advance-

[boats.net]

No rarely see problems with water tube, check exhaust tuner(muffler) is not damaged causing excessive heat on water tube.