Here's a bit of a multi-season folly but in the course of installation, I discovered a few more things about how the boat was put together. This is definitely a project that I never would have considered if it hadn't fallen into my lap. One day I was scanning the "boat parts" listings on Craigslist and saw an ad for a 5000 BTU Webasto heat pump - only $300! Those things cost almost $2K new. Certainly when you add the circulation pump and hoses. And the photo looked like new. I couldn't resist checking it out. And ended up coming home with it.
The seller was this crazy Russian dude who was trying to use it to cool the sleeper cab of his truck. "The heater works sometimes, but cooler is No Good...."
"Uh... how are you working the seawater loop?"
"Oh, just plumbed it into the trucks radiator. It should work!"
"
,."
I got it home and bench-tested the unit - it seemed to work just fine, as long as the input water was within the specified range of 40° - 90°F. Now 5000 BTU is a bit on the small side. It's the smallest unit they make. But the cabin of my boat is pretty small. On the other hand, the climate where I live doesn't really require an air conditioner, except for a couple of weeks a year, usually. Hardly worth the effort. "But this thing heats, too," I tell myself, "and it's really about the same size as the oil-filled radiator I've been using. And it would be permanently installed, not banging around underfoot or in a locker. And you know, someday: Baja." Well alrighty then. It's a go!
The first problem was where to put the thing, on such a small boat? The unit should be as close to the sole as possible and the output duct as high in the cabin as possible. For cooling, anyway. The opposite logic would apply for heating. Well, I really don't want to put any more permanently installed weight on the port side. And as it happens, the "duct" at the hull deck joint runs the entire length of the starboard side (almost) and isn't really doing anything... might it make a good HVAC duct? The unit, with its required clearances, is basically a cube 12"x12"X12". Doesn't quite fit under the settee. It might (barely) fit inside the V-berth locker, if the opening were nibbled a bit wider, and some kind of supporting cleats glassed in. However, that's where the holding tank, macerator, and associated plumbing are located. That stuff would all have to be moved. And it was a colossal pain to route all those heavy hoses through there in the first place.
Well, it sits nicely in the aft corner of the V-berth... and one of my doodles in the "future projects" layer of the boat drawings has added cabinetry in that space. Hmmm. And it's directly below the "duct" mentioned above. And it's just a few inches from the toilet, so the plumbing might easily be tee'd right in. And just in case this all doesn't work, it could be easily removed. Et voila! Order up a hardwood grille from Amazon and we have a new HVAC locker! (Mea culpa: re-using these first couple of photos.)
A hole saw and a cheap flange adapter get us into the "duct," with about 15 inches of dryer vent tube from Home Depot. (The marine places sell "HVAC Ducting" for this application. Beware, it turns out to be just about an inch of fiberglass insulation glued to aluminum foil and wrapped into a tube. Pretty much worthless, though costly.)
But wait... it turned out that the "Duct" wasn't quite as ready-made for this purpose as I had hoped. First, the end of the "locker" portion was mostly sealed off from the rest of the "duct" portion by a thin wrap of fiberglass - and hidden away behind the cleanout and vent hoses. Which were a real rodeo to get in there in the first place. Just removing that little piece, with a trim saw wielded at arm's length, took a whole evening.
Then, I had to seal that end of the irregular-shaped duct off from the rest of the overhead locker. I tried and failed (so far) to figure out how I could pattern a piece to fit in there. So "for now," I just stuffed a leftover piece of cushion foam in there.
Then I discovered that the aft end of the duct was actually wide open to the cockpit coaming and the aft lazarette. Stuffing a piece of foam behind the Q-berth grille (coming up next) didn't really seal it off. So for now, I'm heating and cooling the whole boat, not just the cabin. Holding my phone up inside the coaming (through the winch access hole) reveals this interesting shot. The top of the duct is the opening at the bottom left of the photo. Bottom right is the top of the Q-berth liner. Top is the winch platform, with the bolts of the secondary and a cleat showing. Behind there is the engine room intake vent hose. Is that messy thing at the left the hull-deck joint? Not taped up so solid as we have been lead to believe! Actually, I think it's another joint a couple of inches above the HDJ. At this point, the "side deck" is only about three inches wide and a sort of inward flange appears to have been built up in the mold to support that where the coaming joins in.
But back to our current problem. I'm going to have to remove the Q-berth shelving, and duct cover and somehow glue a top into the duct. Another tedious mini-project. But first, let's find out if this AC thingy is even going to work.
"For Now," I've just put the blocking foam aft of the salon grille. Speaking of which, the grilles were about the easiest part of the whole project. They're "West Marine" brand ABS vent grilles that match the smaller vents I've installed on some of the other cabinets. Jut cut a hole in the plywood duct covers and put on over the bookshelf in the salon and another at the aft end, over the Q-berth.
Next, I had to consider the plumbing. The heat pump exchanges heat with a seawater loop, and according to the directions, it wants its own set of through-hulls. An intake below the waterline and a discharge through-hull just above the waterline. It could be plumbed all the way to the transom, or I could drill a hole in the topsides just adjacent to the HX.
A couple of cautionary tales about that! One time I noticed a boat in a marina where I was staying that seemed to have the bilge pump running almost constantly. It would run for a long time, then shut off. But next time I looked over, it was running again! I figured there was probably a pretty serious leak and that boat was in danger of sinking. So I went to find the marina manager. "Haven't you ever seen a marine air conditioner before?" D'Oh!
Another time, I spent a week on a Hunter that had a bilge pump through-hull in the topsides. We were tied up alongside the guest dock, and a sort of pot-luck happy hour party broke out on the dock. People pulled up deck chairs and ice chests to sit on. Suddenly that side-dicharging bilge pump kicked in and hit one of the partiers square in the back! "Hey! Your boat just pee'd on me!"
So there are some potential downsides to that! Plus, jeez, cutting more holes in the boat before I'm even sure this thing is going to work!?!??
So, "For Now," I just plumbed the heat pump in parallel with the toilet. I installed the circulation pump below the waterline in the bottom-most corner of the settee. Added a new strainer, and Tee'd off the toilet intake. D'Oh, didn't sufficiently allow for the minimum curvature of the tubing, so had to relocate one of the brackets after the fact.
For the discharge, I replaced the tailpiece of the lavatory sink with one that has a "tee" inlet for a dishwasher. It fit perfectly. So the risk here is that the intake and the discharge are only about a foot away from one another. Can we assume that the ocean (or river) is an infinite reservoir, or could we get cross-flow between the two through-hulls? And will this create a "gurgle" sound in the drain that would be more annoying than the "tinkle" of discharge from an above-the-waterline through-hull? If it works, there would be no tell-tale discharge stream. Everything would be calmly operating below the water.
And finally, I ran a safety-cable back to the AC (the other AC) panel and installed a new breaker. Yay! I finally got to use the pre-printed "Air Conditioner" label. Good thing I've held onto those. The unit only draws 5 amps, so it could be powered by a suitcase generator, away from the dock. If that were a needed thing. Then I installed the control unit on the chart table. It also comes with an infrared remote control. So one could operate it while laying in the Q-berth, which is about the only place with the right angle on the remote.
Finally, the moment of truth... It works! Hot air comes out and warms up the boat. (Haven't yet really tested the cold air thing - when the weather was unreasonably hot last summer, we did not sit around at the dock! I mean, it puts out cold air, but we didn't wait for the boat to cool down.)
But man, this thing is noisy! There's the fan noise, the pump noise and, yes, a very faint gurgle can sometimes be heard from the drain. As far as heating, it has about the same effect as the cheap, silent, oil-filled radiator. (Although circulation fans are needed for that to make the boat comfy.) For all the trouble and cost, and the fact that it will stop working when the river gets colder, I couldn't recommend this thing as a heating solution. I hope it picks up the slack with cooling and dehumidifying!
Oh, speaking of the dehumidify function, the condensate just drains from the tray at the bottom of the unit. "For Now" I've got a tube carrying it to the bilge. Really should tee in to the drain, but since it has to go strictly by gravity, that one's a bit trickier.
The seller was this crazy Russian dude who was trying to use it to cool the sleeper cab of his truck. "The heater works sometimes, but cooler is No Good...."
"Uh... how are you working the seawater loop?"
"Oh, just plumbed it into the trucks radiator. It should work!"
"
,."I got it home and bench-tested the unit - it seemed to work just fine, as long as the input water was within the specified range of 40° - 90°F. Now 5000 BTU is a bit on the small side. It's the smallest unit they make. But the cabin of my boat is pretty small. On the other hand, the climate where I live doesn't really require an air conditioner, except for a couple of weeks a year, usually. Hardly worth the effort. "But this thing heats, too," I tell myself, "and it's really about the same size as the oil-filled radiator I've been using. And it would be permanently installed, not banging around underfoot or in a locker. And you know, someday: Baja." Well alrighty then. It's a go!
The first problem was where to put the thing, on such a small boat? The unit should be as close to the sole as possible and the output duct as high in the cabin as possible. For cooling, anyway. The opposite logic would apply for heating. Well, I really don't want to put any more permanently installed weight on the port side. And as it happens, the "duct" at the hull deck joint runs the entire length of the starboard side (almost) and isn't really doing anything... might it make a good HVAC duct? The unit, with its required clearances, is basically a cube 12"x12"X12". Doesn't quite fit under the settee. It might (barely) fit inside the V-berth locker, if the opening were nibbled a bit wider, and some kind of supporting cleats glassed in. However, that's where the holding tank, macerator, and associated plumbing are located. That stuff would all have to be moved. And it was a colossal pain to route all those heavy hoses through there in the first place.
Well, it sits nicely in the aft corner of the V-berth... and one of my doodles in the "future projects" layer of the boat drawings has added cabinetry in that space. Hmmm. And it's directly below the "duct" mentioned above. And it's just a few inches from the toilet, so the plumbing might easily be tee'd right in. And just in case this all doesn't work, it could be easily removed. Et voila! Order up a hardwood grille from Amazon and we have a new HVAC locker! (Mea culpa: re-using these first couple of photos.)
A hole saw and a cheap flange adapter get us into the "duct," with about 15 inches of dryer vent tube from Home Depot. (The marine places sell "HVAC Ducting" for this application. Beware, it turns out to be just about an inch of fiberglass insulation glued to aluminum foil and wrapped into a tube. Pretty much worthless, though costly.)
But wait... it turned out that the "Duct" wasn't quite as ready-made for this purpose as I had hoped. First, the end of the "locker" portion was mostly sealed off from the rest of the "duct" portion by a thin wrap of fiberglass - and hidden away behind the cleanout and vent hoses. Which were a real rodeo to get in there in the first place. Just removing that little piece, with a trim saw wielded at arm's length, took a whole evening.
Then, I had to seal that end of the irregular-shaped duct off from the rest of the overhead locker. I tried and failed (so far) to figure out how I could pattern a piece to fit in there. So "for now," I just stuffed a leftover piece of cushion foam in there.
Then I discovered that the aft end of the duct was actually wide open to the cockpit coaming and the aft lazarette. Stuffing a piece of foam behind the Q-berth grille (coming up next) didn't really seal it off. So for now, I'm heating and cooling the whole boat, not just the cabin. Holding my phone up inside the coaming (through the winch access hole) reveals this interesting shot. The top of the duct is the opening at the bottom left of the photo. Bottom right is the top of the Q-berth liner. Top is the winch platform, with the bolts of the secondary and a cleat showing. Behind there is the engine room intake vent hose. Is that messy thing at the left the hull-deck joint? Not taped up so solid as we have been lead to believe! Actually, I think it's another joint a couple of inches above the HDJ. At this point, the "side deck" is only about three inches wide and a sort of inward flange appears to have been built up in the mold to support that where the coaming joins in.
But back to our current problem. I'm going to have to remove the Q-berth shelving, and duct cover and somehow glue a top into the duct. Another tedious mini-project. But first, let's find out if this AC thingy is even going to work.
"For Now," I've just put the blocking foam aft of the salon grille. Speaking of which, the grilles were about the easiest part of the whole project. They're "West Marine" brand ABS vent grilles that match the smaller vents I've installed on some of the other cabinets. Jut cut a hole in the plywood duct covers and put on over the bookshelf in the salon and another at the aft end, over the Q-berth.
Next, I had to consider the plumbing. The heat pump exchanges heat with a seawater loop, and according to the directions, it wants its own set of through-hulls. An intake below the waterline and a discharge through-hull just above the waterline. It could be plumbed all the way to the transom, or I could drill a hole in the topsides just adjacent to the HX.
A couple of cautionary tales about that! One time I noticed a boat in a marina where I was staying that seemed to have the bilge pump running almost constantly. It would run for a long time, then shut off. But next time I looked over, it was running again! I figured there was probably a pretty serious leak and that boat was in danger of sinking. So I went to find the marina manager. "Haven't you ever seen a marine air conditioner before?" D'Oh!
Another time, I spent a week on a Hunter that had a bilge pump through-hull in the topsides. We were tied up alongside the guest dock, and a sort of pot-luck happy hour party broke out on the dock. People pulled up deck chairs and ice chests to sit on. Suddenly that side-dicharging bilge pump kicked in and hit one of the partiers square in the back! "Hey! Your boat just pee'd on me!
" So there are some potential downsides to that! Plus, jeez, cutting more holes in the boat before I'm even sure this thing is going to work!?!??
So, "For Now," I just plumbed the heat pump in parallel with the toilet. I installed the circulation pump below the waterline in the bottom-most corner of the settee. Added a new strainer, and Tee'd off the toilet intake. D'Oh, didn't sufficiently allow for the minimum curvature of the tubing, so had to relocate one of the brackets after the fact.
For the discharge, I replaced the tailpiece of the lavatory sink with one that has a "tee" inlet for a dishwasher. It fit perfectly. So the risk here is that the intake and the discharge are only about a foot away from one another. Can we assume that the ocean (or river) is an infinite reservoir, or could we get cross-flow between the two through-hulls? And will this create a "gurgle" sound in the drain that would be more annoying than the "tinkle" of discharge from an above-the-waterline through-hull? If it works, there would be no tell-tale discharge stream. Everything would be calmly operating below the water.
And finally, I ran a safety-cable back to the AC (the other AC) panel and installed a new breaker. Yay! I finally got to use the pre-printed "Air Conditioner" label. Good thing I've held onto those. The unit only draws 5 amps, so it could be powered by a suitcase generator, away from the dock. If that were a needed thing. Then I installed the control unit on the chart table. It also comes with an infrared remote control. So one could operate it while laying in the Q-berth, which is about the only place with the right angle on the remote.
Finally, the moment of truth... It works! Hot air comes out and warms up the boat. (Haven't yet really tested the cold air thing - when the weather was unreasonably hot last summer, we did not sit around at the dock! I mean, it puts out cold air, but we didn't wait for the boat to cool down.)
But man, this thing is noisy! There's the fan noise, the pump noise and, yes, a very faint gurgle can sometimes be heard from the drain. As far as heating, it has about the same effect as the cheap, silent, oil-filled radiator. (Although circulation fans are needed for that to make the boat comfy.) For all the trouble and cost, and the fact that it will stop working when the river gets colder, I couldn't recommend this thing as a heating solution. I hope it picks up the slack with cooling and dehumidifying!
Oh, speaking of the dehumidify function, the condensate just drains from the tray at the bottom of the unit. "For Now" I've got a tube carrying it to the bilge. Really should tee in to the drain, but since it has to go strictly by gravity, that one's a bit trickier.
