Replumbing an Outboard for Heat

Agreed.

Like you, I have no facts for such, but I strongly suspect that if you identified all the outboards in the world and where they operate, a higher percentage would be in temperate to tropical climates.
As such, only the engine would require attention to the temperature is at... other than feeding off for some portal a/c unit

 

Only one person not on topic...!!!

Good luck with the headache... i'm still awaiting my booster

 

I am not necessarily concerned with commercial opportunities. I was commuting up Indian Arm last week, during our spectacular monsoon season, in a friend's excellent aluminum cabin boat. He had paid an extra 3500 for the diesel heater, but in hammering rain, at 90% rH, where all 3 of us were wet, it just couldn't clear the windows. The entire trip we were wiping the windows, as a survival necessity. With the massive flooding we are having, there was enough in the water.
We went by an oscillating deadhead that was about 40cm thick, and could easily have been 5 stories long. And invisible a third of the time.
So tremendous amounts of heat, and ventilation are life or death around here.
I don't know what I'll do. I'm not committed to a particular path. But I am endlessly fascinated by engineering challenges, opportunities, decisions made. And I love talking with folks who know more than I do. I can't learn from folks who know less than I do.

 

This thread has cured me of ever wanting to move to a damp, cold climate. Seems every cloud has a silver lining.

 

Sounds like our rainy season!
I have the same issues in my car... however..simple fix ... use the a/c....clears the screen in seconds!

But i suspect your friend didn't have a/c...

 

Did the heater have a duct to defog the windows?

 

It is actually a more complex problem with three wet fellas inside a boat or car cabin. A defog duct may be enough for the helm window..but..

The rh inside the cabin is higher than outside or close to equal. And at 100% rh or close; the only way to get the rh of the cabin lower is to move heated air out of the cabin and exchange it for slightly drier outside air; maybe, hopefully. It wasn't the heating systems fault. It was a sauna.

John-while I may not consider myself an outboard cooling system expert; I am installing a Webasto tsl17 in my build. I have sure marine's real heaters (2) in the cabin. One blows outside onto the windshield which is outside the cabin. This means external air or makeup air must come from somewhere. I expect a cracked window; otherwise I may need a small vent somewhere.

I responded because I had the same notion as you about 2 years ago.

I also installed a maaxdome fan. This would at least move damp heated air out. This one is in the bathroom, but the door can be left ajar for cooking or if things get damp from rainy weather, etc

MAXXAIR 00-03812B MaxxFan Dome with 12V Fan, 6" Diameter - Black Amazon.com https://www.amazon.com/dp/B07TXX79JL/ref=cm_sw_r_cp_api_glt_fabc_0RR2M390WX4RZ1VH7E7D

 

@Ad Hoc pointed out that AC would condense out the extra humidity. Counter intuitive to turn on the ac when wet and chilly, but he's right. That would work.

 

It is common to do that in a car. Run the AC with the heat at maximum to defog the windows.

 

The reason I mention the rooftop fan is because heated air holds more water, so in theory, removing warmer air saturated with water does help remove dampness below the outside rh. This is no different than cracking the car windows with soaked fisherman inside the car. You never really get well dried out, but you may clear the glass this way.

It is certainly not fast. Nor is it as good as AC by any stretch. But DC isn't likely putting AC in that boat and that is as much humor as I can muster this cloudy and cold morning in Minnesota.

I bought Bomon Windows for the Skoota. They include a condensation dam system which I first found to be a bit odd. But what they do is create a dam at the bottom to keep condensation from running into the boat. The dam keeps the water above the drains. And although I am pretty far off OB plumbing; figured John might be interested in knowing their strategy for managing water off the glass includes dams and weepholes.

 

2009 etec

 

So, where would one be comfortable taking off water? You wouldn't want to affect one side vs the other? And you wouldn't want to affect indicator (much)?

Not advocating; just asking.

 

Good question. In this image, the far side cooling water passage is directed into the exhaust. The near side drops out the bottom of the leg. Note the side of the water passages at "8". Same size, from each side of the block. Same pressure, so more or less the same quantity of water flow. Half is dumped out, half cools the exhaust. Taking @baeckmo 's calculations, that's around 30kW available.
Indicator is cold water at "5a", not involved in any way.
In this particular model of engine I'd tap the leg at the height of the "3", let the water drop into a small reservoir, and use a small pump from there. Reservoir equipped with a simple overflow port, so no possibility of back pressure. And a simple matter to return the water to the leg after some heat is extracted.

There are models where all the water is dumped through the exhaust. That is tougher to plumb. But hardly intrinsically difficult. Just need to understand where the water is going in there. Heat of evaporation of water is pretty high. Doesn't take much spray to cool an exhaust. Or again, tap before the exhaust, return as much as needed.

 

Pretty much what I saw as well was tapping the leg. But have no idea how built.. kinda think there is an inner and outer wall