Hot Water Heater Plumbing

Last year, when I installed the how water heater, I never had time to plumb the internal heat exchanger. So, the hot water heater worked fine, but in order to actually get hot water, I had to be plugged in to shore power, or run the generator for power, and then wait for the heating elements to warm the water.

The HWH also has an engine coolant driven heat exchanger inside the unit, so hot water can be created from excess engine heat. That way, when we pull into port, the water is already hot - no need to wait.

So, to hook it up, 2 hoses have to be connected from the engine coolant system to the hot water heater - a supply line, and a return line for engine coolant. I don't like everyday heater hoses, along with conventional nipples and hose clamps, so I decided to use something a little more elegant. I had some left over hose from the oil change system, Aeroquip's "socketless" hose, so I ordered more hose ends, and used that.

For safety and redundancy, I also milled out a couple custom aluminum brackets to mount ball valves in the lines, so if the HWH heat exchanger fails, I can isolate the engine from it. They look like this:

The valves are brass, full port ball valves. You can also see some of the socketless fittings in the pic.

I ran the hoses along the stringers, tucked out of the way, so they won't get stepped on during maintenance procedures. The valves face up, so they can be accessed and shut off rapidly, if need be.

And there it is. The hoses are secured to the stringers every 8 inches or so, and have chafe protection at strategic points, so I don't have any surprises down the road.

Once I was done, I cleaned the entire bilge, and she's now ready for the summer:

Won't be long now!!!

Autopilot - Part 3

     I've been trying to find a good spot for the autopilot computer and pump, so I spent a lot of time staring at the boat, looking around in the engine room, under the dash, and a few other spots near the helm. The pump needs to be spliced into the existing hydraulic steering lines, while the computer can be placed almost anywhere, as long as the required wiring and network connections can be made. The computer requires a power feed, input from the rudder feedback unit, wiring to the pump itself, a network connection, and bonding system connection. So, keeping it near the dashboard and main wiring harnesses is a good idea.
     After looking all around the boat, I decided against placing the pump in the engine room. There are no really good spots in a 340 down there, and service would be easier (and hopefully not needed for a long time!) if I placed the pump just to starboard of the helm station. There is an easily removable storage bin next to the helm, and there is sufficient room to locate the pump and computer in this area. It is also dry and well protected. So, I built a bracket for both items out of 3/4 plywood, and sealed it with 3 coats of marine varnish. It looks like this:

 

     The pump and computer are both on the same bracket, which will be screwed to the decking behind the storage bin. If I need to service anything in the future, I can simply unscrew the bracket, and slide the whole assembly out. Also, much of the wiring is already completed on the bracket, obviating the need to do it in the boat. A terminal strip is on the right side, to facilitate the bonding system connections. Both the computer, and the shield cable from the network are connected to it. In the boat, I'll connect the terminal strip to the bonding system, thus providing an additional level of RF noise rejection.
     On top of the pump, I added three isolation valves. If the pump ever fails, I can close the valves, and retain manual steering. Once in port again, repairs can be handled on my own terms. More to come....

Oil Change System - Part II

One of the things I don't like about most of the hoses in an engine room isn't the hoses themselves - it's the clamps. There is always a little tail sticking out, and it is constantly facing in just the right direction to catch on your clothes, skin, tools, etc. Then they get bent up, so next time, you're even more likely to snag them. So, for the oil change system , I decided to go with Aeroquip Socketless hose and fittings (Fragola makes a similar product). These are one-way barbed fittings that mate exclusively with purpose designed hose, and don't require clamps under lower pressure applications. Clamps can be added for additional pressure rating, if required. The fittings have to be pre-oiled, and the hose heated in hot or boiling water for installation. Once the hose is slipped over the fitting, the only way to get it off is with a sharp knife. The hose itself has a rugged outer braid, for increased burst strength and abrasion resistance. The finished oil change system, without the cover, looks like this:

 Each hose is secured to the bulkhead just below the connection point. They are then routed to each transmission, each engine, and the generator. At the generator, I had previously machined an aluminum block to act as an access point for oil changes, so I kept this block in place, and connected the oil change system hose to it:

I have to remember to open this valve when I change the generator oil, but I like having an additional valve at the generator, for redundancy.

For the engine oil pans, I had two choices. I could have changed the elbows at the oil pan, where the dipsticks attach, to tees, and then added my oil change lines. But, the potential for sucking air through the dipsticks exists, and then all the oil is not extracted form the pan (not that last little bit, anyway). So, I removed the drain plug from the other side of the engine oil pans, and, using them as a guide, machined my own drain fittings. These are a metric thread on one side, with an O-ring seat that seals to the pan, and a -8 AN male fitting on the other side, to mate with my new oil lines. And no, you won't find these in a hardware store. The finished engine lines look like this:

The transmissions were the simplest to change over, since they already use a 1/2" NPT pipe thread. I just removed the existing plugs, and threaded in some 90 degree pipe to AN adapters:

Once all the lines were secured every 8 inches, I just had to add the pump cover, and make up a discharge line. I built a small hanger, and mounted it to the bottom of the deck, so when the hose is not in use, it has a secure storage place. I also made up an aluminum plug for this hose, so when I'm done using it, I can plug it to prevent any drips from getting into the engine room. It looks nice too...

I'll make up some labels for the valves, and it's done.