Bus Heater, Keel Cooling

[fritzdfk]

I have a 26' trawler with an inboard three cylinder Yanmar diesel. This boat is unusual in that it has keel cooling and dry exhaust. The boat is 30 years old and I am surprised that no one has ever put a bus heater in it. I have only had the boat a few months and am doing a major rehab. It is not in the water and hasn't been for 6 years or so. Any way I want to add a heater that runs off the engine coolant system. The existing system is very simple. From the engine mounted pump to the keel cooler then to the manifold and back to the pump. Do I just extend the system to the heater. Pump - heater - keel cooler - manifold - pump? I think there should be a bypass in case the heater core springs a leak. Is it this simple?

 

[The Q]

You'd definately need the bypass, not just for leaks, but also to switch it off so you don't get too hot in your short summer.

I have seen what you're proposing being used, I've also seen a system where the Heater is taken off before the thermostat in the engine so that it heats the cab heater long before the keel cooler . This is a similar system to that used in road transport, and would be a better choice if you have the access points on your engine