Here in the upper midwest, the evenings can get cool. Especially in the Fall when the fishing picks up. A week or so ago, I was aboard a deckboat owned by an acquaintance. He had a heater installed. Apparently the boat has a heater core hooked into the engine cooling system and from that core he had two dryer vent hoses running up either side of the boat to the console where heat was expelled to the passengers. I can't say if there was a blower to force more air through the system, but even a little heat would be a welcome thing. Anyone have any thoughts on how this might be safely rigged up in the engine compartment of a Mercruiser 898?

There is a company that makes units for boats. On my diesel I would put it series with my water heater that is in the thermostat bypass circuit (just like on a car). Check out the article on coolant circuits maybe some other idea appeals to you more.

Thanks, Marcus, I was sure that someone here would have the answer for me. It looks like a pretty simple installation.

There are a couple of companies that make these units. I had one that was made by heater craft. Hamiton marine sells them. It has a variable speed 12V blower and you tap off your engine the same as a hot water heater. You should be able to get plenty of heat out of your engine. I think they are 28,000 btu and 40,000 btu. If you can route a discharge hose to your windshield it will also work as a defogger.

HTH

John

I have installed a hydronic heater made by heater craft. I selected "there are others available" the 4 zone heater which has a 4 position 3 speed blower switch. It runs on 12 volt and has a heat exchanger that draws heaat from the diesel engine cooling system . The install was involved due to compartments in a pacific seacraft which required big hole drilling for the ductwork, but the end result is major comfort for my family. The 38 HP Yanmar provides an excellent heat source and warms the water in a few minutes which means warm air for the vessel. This is a DIY task with basic tools and a basic understanding of engine cooling and 12 volt power systems. Heater Craft customer support was excellent. I have used this product for 3 years in upper Michigan and can find no fault with it.