I removed E-33's about 10 years ago. Rust problems. Removed the outer sheilding (thin sheetmetal) and the core fit out the seat hatch. All fitting were removed as I recall. I no longer have a water heater, and the limited cooling thru heat exchange it provided was minimal. No adverse impact. Bought her new in 1984 may someday replace, but we nolonger race, or cruise the bay, mainly day or over night sails, so see no practical need for the water heater. Would imagine some of the ss water heaters available after market would be a simple replacement.
Cheers,
Bill Montgomery
IMPLUSE, Hayes VA