Good elbow, bad water heater

[Sanders Lamont]

A report on my aging 37c:A first for s/v Good News: I took her into the boat yard and it actually cost me less than I expected!-- The exhaust system had about 400 hours on it (since it clogged and blew in San Diego) so I had the mechanicic take it apart and check it. No soot buildup and everthing looked fine. The engine apparently does better when run at higher rpms (over 2500) periodically-- less buildup. -- Battery isolater wasn't isolating, it had been unwired some time in the past, and the yard said that was appropriate for the setup and to leave that as is, just use the rotary switch and keep the starter battery offline when at anchor/unplugged.-- Heat exchanger was dismantled and cleaned, new zinc, and I'll do that job myself next time.-- I now own a brand new hour meter, which actually works.-- Two strong young guys lifted the old kerosene stove out and put it by the dumpster, and I am now modifying the space into a cabinet with stove-top burners.-- rewired the battery charger so it actually charges the starter battery as well as the house bank, an oversight by the original installer.I thought it might take three days in the yard. Took less than a day at Oakland's Britich Marine and one-half a boat buck. I had estimated it to be almost four times that going in, but they were very straightforward and quick.The bad news is that the yard folk did not really want to mess with removing/replacing the dead hot water heater. On close examination we found the original owner glassed in every bulkhead and panel that would normally allow access. I crawled into and around everything later and confirmed what they said: the only way to get the old heater out is to saw large holes in panels, endangering various wiring bundles, and saw the heater into chunks. (Even the bulkhead aft of the engine has been reinforced and glassed in)I reviewed all the previous archived discussions and have decided to adopt the recommended Vietnam War approach: Declare victory and leave it alone. I will eventually find a place for another heater. Suggestions welcome.Back at the home dock I managed to isolate the old heater pipes, replumb the cold water circuit, and I have the water system working again. When in doubt: jury-rig.And then it rained very hard for hours, and the ten new ports I installed last Fall all were dry. Not a drop.Of course, a new leak developed through a traveler bolt, but that was a quick fix (particularly after dealing with re-plumbing the water system).Next week, we sail and do no work.Sanderss/v Good News

 

[John Brecher]

Heat exchanger cleaning

Sanders,Last weekend we went to Petaluma and got a high temperature alarm in the river. I suspected lack of raw water flow and by disconnecting at various points and blowing in by mouth was able to isolate the problem to the exhaust manifold water outlet. After scraping and flushing my problem was cured.I am interested in your assessment of how easy cleaning of the heat exchanger is. You say next time you would do it yourself. My guess is the trickiest part would be getting the side covers to seal properly on the tubing bundle. Also you would want to have a full set of gaskets and O rings on hand.I would appreciate your comments.John Brecher

 

[Sanders]

John, Mine is an aftermarket design added on

That means we avoid salt water in the engine jacket, and it works well.The unit hangs on the panel on the starboard side of the engine and looks like two copper/bronze tube, one atop the other. It showed green corrosion on both ends and around the attached hoses. Some folks take it off the wall and into a shop to clean, but when the mechanic cleaned it he just removed both ends with a wrench, set those and the gaskets aside, and then cleaned everything he could reach with a wire scrub brush. He did it all in place.He cleaned the insides of the small inner metal tubes with a piece of stiff wire to make sure they were not blocked. Then he removed the old zinc and replaced it, cleaned the gaskets (turned one around to present a fresher face to the metal, and re-attached everything.When I did this several years ago I worried that the back end would strip, and tried to clean it from just one end, which was not adequate. Even at my very slow pace, the entire cleaning takes less than an hour.When he was done he recommended that I use primer paint to recoat the surfaces.Incidentally, he did not feel the unit was creating any problems. He said that most heating problems seem to come from the salt water intake being clogged. Cleaning that is much simpler, as you only have to remove the strainer basket, wipe it all clean, and reattach and re open. That's a ten minute job at most.From your description it sounds like your problem was on the outflow end, not the intake, and I would suspect soot buildup on the elbow joint. That can be cleaned too, but I wanted to see a real mechanic do it before I tried it. He had to crawl into the back of the engine compartment to reach it, and he replaced the gasket while he was at it. He just undid the joint, visually inspected it, and stuck his fingers up inside the check for buildup.Several years ago mine clogged, the pressure blew the engine water hoses, burned a hole in the exhaust, and ended up shooting soot all over the engine compartment and the galley area. That was a mess and expensive to repair, so I have sworn to check that elbow joint every 400 hours or so.Mechanic said the cause was running the engine consistently at too low rpm, and ever since I make sure I run it hot for a while on the way back in, even if for ten minutes.Sanders