That would be by understanding as well Danny. The suggestion from Jamie's latest technician is that there may be water inside the engine via the exhaust due to low engine compression not pushing out the raw water via the exhaust.
I would think that is very unlikely. However, if there is, or was seawater in the engine,then how did it get there?
There has been much discussion about low compression.
Given that the engine initially was cold cranked and didn't start, then the sea water drained from the exhaust, etc. ( to avoid flooding/ hydraulic action) which would allow the engine to crank again. Could it be possible that either the valves are bent, or incorrectly seated as a result of the hydraulic effect of sea water, i.e. engine now cranking but not enough compression to fire?
Until some one who knows what they are doing looks in side the engine , it is all speculation.