Heating system Swan 48

Dear friends,

does anybody know if there was a orignial way or a drawing where to put the pipes of the heating system, the exhaust, etc..

We have some remaining signs of a former existing heating system but we would like to renew it in the next weeks.
Just bought a 5kw Webasto heater.

Any information on that would be helpful!

Ulli
SY Themis

Dear Ulli,

supposing that while not having the drawings, some experience with installing a heating on a 48 might help ...

We installed a new heating system two years ago. In preparation, I found all the holes that were intended for the air ducts on the port side of the boat. They have diameters of about 10-11 cm. Starting (or ending) at the aft bulkhead under the port berth in the aft cabin (see pic), they lead forward to the front cabin. If needed, I can post more pictures, but provided Themis has the same arrangement, you will find them.
When we installed the heating, I was advised not to install an air heating, as the tube/duct length would be too long. Installing the heating unit in the stern compartment, the distance to the front cabin would exceed 12 m. My technical advisor said hardly any warm air would arrive if the distance is more than 8-9 m, in particular not if more than one room was on the way. I argued that the boat once had such a system, and he said that was in the Seventies when nobody knew about today's legal limits regarding installations below deck.

So I installed a water-based heating (in the stern locker) with four separate heat exchangers (and fans) in the aft cabin, the saloon, the front head and the front cabin. The tubes for the water circuit make use of the holes for the old air ducts. That will not help you, but if you need any pictures of the installation or how the heating unit is installed in the locker, let me know.

Best regards from Bremen,
Martin (48/039)

openings for the air ducts under the portside bunk in the aft cabin

Hi Martin

Happy new year.

Just about to install a Webasto ThermoPro 90 water heating system to Snow Wolf. Like you we have the air ducting holes on the port side from a system that was removed a long time before I got the boat.

Any pictures of where you fitted the exhaust outlet or any things you would do differently would be appreciated.

Happy New Year to you as well! 

I'll quickly attach a picture of the exhaust position for the Webasto heater. As you can see, it is left of center in the transom (the round opening next to Vellamo's home port). We have the heater mounted in the stern compartment, so the exhaust pipe is as short as possible, includes a gooseneck to prevent water flowing back into the heater, and the through-hull is still easily accessible. 
The transom of the 48 does not submerge even when sailing hull speed (that's important as the exhaust pressure is not sufficient to allow the heating to run when the exhaust is submerged). There are few drawbacks to this solution, one is that when the wind is from aft, exhaust fumes enter the companionway into the boat. I have not tested conditions in which Vellamo would be pooped by a large wave overtaking the boat. After more than 50,000 nm with this boat, I haven't even encountered such a condition, which speaks greatly for the boat ...

I'll think about what I'd do differently and post asap.

Best regards,
Martin  

Stern view, exhaust through-hull next to home port line

Two more sketches of the heating installation on Vellamo.

We built the heating system in two stages. First we only went along the port side of the boat; there are four heat exchangers and a total of nine air vents. The hot water tank is connected to the heating so we can produce hot water either by shore power, by the engine, or by the Webasto heating. The heating circuit is run with anti-freeze instead of water and has an own boiler that can "pre-heat" the circuit by shore power. 
Then we relocated Vellamo's sailing grounds to the very far north and found that while the heating power was still sufficient, there was considerably more condensation on the starboard side. The warm pipes of the heating prevent a lot of condensation by warming the inside of the hull. Therefore, we extended the circuit to the starboard side and added another heat exchanger to let a warm airflow into the oilskin locker. 

On the second sketch you can see roughly whereabout the components found their place. The circuit runs (and descends) from the burner in the stern compartment under the bunks on the port side, then rises again in the fore cabin to cross to starboard, and from there descends again to the starboard aft bunk. The rise in between required an additional circulation pump.

If I'd do it all over, I'd make sure the pipes are close to the hull more or less following the waterline -- that is where the condensation maximizes. I'd make sure there is either warm ventilation or at least a warm pipe in all the lockers. And I would probably build a single circuit (port side forward, starboard back) instead of the two-way we have now, saving half the length of pipe.   

I hope the sketches are clear enough -- if not, just ask.

Best regards,
Martin

First stage (solid lines) and extension (dotted lines)

Heating circuit