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Thermostat for heat

Rush

Rush

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Hey guys I got a 1990 7.4 27ft. stingray cabin cruiser that I'm installing a heater in for fishing/winter boating. Basically a heater core with a fan. The boat is saltwater cooled with a Mercury OEM 143 degree thermostat I'm thinking 180 or 195 degree thermostat to get enough heat out of this heater. I'm concerned about oil temp in summer if I leave it in. Any ideas on this. heres a link to the heater. http://store.hamiltonmarine.com/bro...u-12v-basic-kit-w-4-outlets-117070/4,218.html When we go fishing it can easily be as low as freezing temps during Rockfish season.
 
Note that it says "Closed Cooling System" in the ad. I think raw Bay water flowing through that thing will eat it up in no time.
 
Ted said:
Note that it says "Closed Cooling System" in the ad. I think raw Bay water flowing through that thing will eat it up in no time.
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Thanks for the reply, but I plan on flushing and installing shut off valves in the summer. I need the heater even if it only last a few years.
 
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You likely could get by with a hotter thermostat and oil temps would be fine. I had stock 160 thermostats in my 502's and had trouble getting enough oil heat to evaporate off the condensation. BUT, you may have issues with detonation and or high exhaust temps that could cause issues. Best solution might be use a stock thermostat after May and swap for the warm one when the water cools in September. It's pretty easy to do.
 
Ted said:
You likely could get by with a hotter thermostat and oil temps would be fine. I had stock 160 thermostats in my 502's and had trouble getting enough oil heat to evaporate off the condensation. BUT, you may have issues with detonation and or high exhaust temps that could cause issues. Best solution might be use a stock thermostat after May and swap for the warm one when the water cools in September. It's pretty easy to do.
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Thanks Ted, this kinda the way I feel, I have been concerned about oil temps being low with this low of thermostat temp I have now. I guess Ill do some experimenting with thermostats like a 180 first. so many variables to look at. Last summer when I got the boat it would run hot, we installed through hull water pickup, cool as can be now, a little concerned about water pressure being high, runnin to cold I don't know. The boat is bone stock except for the water pickup. It has no water pressure gauge or oil temp gauge either. Thinking of installing these gauges so I really know. I try to keep things stock for reliability. Thanks again Ted, We will see. :rolleyes:
 
Thats a good point Chris. When trolling rpms are at as low as 5,6, or 700 rpms I'm not sure even a high amp alt will keep up voltage. I have a friend with a heater like I want to buy that heats very well. I think I will go down to his boat and ck it out. He is running newer motors with fuel inj that I'm sure run hotter. The guy that installed his past away. I'm still open for any input about this as I will listen and try to make the best decision with all the info I get. Thanks!
 
I am an auto tech.... I would safely assume that a heater core will deteriorate very fast in salt water even with flushing. And how the system works in a car is very different. There is a case that forces air through the core only using all of its surface to produe heat. You would not have that efficiency if you had a core sitting there with a fan on it. Also, Most vehicles today are eqipped with a heater core control valve in the cooling system that will limit the flow through them due to the fact that they can actually cool the vehicle down fast enough to maintin a good operating temp to produce heat. A heater core is like a little crappy radiator. And we also call them the cooling system filter because of all the junk that gets trapped in them.

I would go electric. That is your best bet.
 
If you heat saltwater above 180 F reguarly you will have serious cooling issues. Saltwater will turn solid at high temps.
Steve
 
Definitely good points everyone, I sent an email to the manufacture of the heater unit. I guess if I added fresh water cooling this would fix corrosion problems. The engine room is very small and hard as hell to get to the sides or front of the engine. I realy don't want or need a generator, when fishing I don't want the noise when its time to relax. :cheers2:
 
Don't most of the cruisers use a propane unit?


The Point Fixer maxes is a good one- the passages in a heater core are tiny.
 
On the Chesapeak which is salt and/or brackish, if you raise the engine temp past 160* you'll get a lot of salt crystalization and scaling in side the engine, don't do it!
 
Thanks everyone really, I talked to the co that builds it. they said it would still have one year warranty but they were not sure how long it would last. they guessed with flushing it would help a lot. unlike a heater core with small passages it has 3/8th. tubes. they also recommend a 160* thermostat anyway for the thing to work. I hate someone to ask a me a question and then argue with me so please don't get that impression. all these points are important. If I had the room I would have used a propane heater. I plan on installing this in the aft cabin and ducking into the helm seat useing the seat as a kind of air handler so it would heat the seat as well and just put vents in the seat where I need them, with 1 heating the cabin.

I found on this boat I freeze my ass and feet off. you really can't close off the back but so much, so as to grab the fishing rod when the fish hit it. I will need the heat in November/December and April/May.
 
You're not going to get that sort of output from an electric. It'll keep an enclosed space a bit warmer, but they take a while. And your point on the output of an alternator on an engine turning 700 rpm is another strike against the idea.

If you are going to pursue the water heat, I'd grab water from where it's exiting your exhaust manifolds- if possible. Remember, that water may leave your engine at 120 or so, but it's going to pick up a bunch of heat in the exhaust. You may have to set up some sort of idle speed diverter.
 
One of my fishing buds has a portable propane heater that he only puts in the pilot house (25' Parker) when it's cold outside. He ran a long hose out to the back of the boat and straps a propane tank down out there. Works great!!!! ....but I really don't know how safe (or legal) it is. Sure feels good when we're catching Stripers in December!!!! :D:sifone::cheers2:
 
How about venting some of the engine compartment heat to the helm station. Did that on a older boat I owned (twin setup) via a blower fan. It was not the hottest air but it took the chill away. Pete
 
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