The 'hell hole' is the space beneath the floor of the aft cabin, the space outboard of the center water tank on port side, beneath the fuel tank area.

The exhaust is entremely hot and must be routed to take this into account. That, frankly, was my biggest safety worry.

Normally I don't sleep with the Espar running, unless it is near-freezing outside air temp, but that's not from safety concern...just that we like it cold at night. But theoretically the system should be safe enough - if installed properly - that it is usable anytime, just as is your home furnace.

Wally : You might want to check out Hydronic Heaters vs. the Forced air systems. Hydronic uses a water heater and radiators and thus the lines are much smaller and easier to install than the air ducting - unless your 36 already has the air ducting installed. [url]http://www.itrheat.com/hydronic.html[/url] I have no connection with this outfit nor can I vouch for them but they have a good web site which describes their hydronic system well.

Tom

I just had an Espar Airtronic system installed by my marina. Hasn't been cold yet, so I can't comment on the comfort factor yet, but here are some observations so far.

As stated above, the exhaust is pretty darned hot for about the 1st 3 feet. It is a double wall hose comprised of an inner tube, a 'fiberglass sock' and an outer hose. I had the unit installed in the cockpit locker; the exhaust goes forward, loops up along the hinge for the seat, then descends below the propane locker. The exhaust fitting is installed in the vertical part of the transom, just to the right as you walk out on the swim platform. This has the hose partially restricting access to the port side lazarette. This could be avoided by placing the exhaust port elsewhere, but we agreed it was the most protected from being submerged while sailing.

I originally thought I could share the ducting with an A/C unit, but was advised that A/C hose is not suitable as, a) it's not heat resistant and b) heater hose is not large enough. The hose exiting the heater is 4", which reduces to 3" and 2" after junctions. A/C can be as large as 6".

The ducting runs forward through the storage above the fridge and stove, into the portside/aft cabinet, down through the seatbacks, through the head to the forward cabin. The primary vent (can't be shut off) at the end of the aft dinette seat, right by the drawers by the sink. There is a vent in the head and one in the forward cabin, on the bulkhead shared with the head, under the seat. The run to the aft cabin runs aft under the heater unit, down through the lazarette and to a vent in the aft bulkhead.

The control unit is at the nav station.

I knew I'd lose some storage, but was pleasantly surprised. The 4" hose routed through the cabinets above the stove is attached high along the trim strip. It has almost zero affect on storage, tall drinking glasses fit under it fine. Being 6' tall, I don't even see it (my short wife probably will). The runs through the seatbacks was also kept high, pretty much zero impact. I can't get quite as much under the head sink as before, but still have my head treatment in there.

My primary concern is the hot exhaust hose. I'm going to further insulate the first 3-4 feet with additional heat resistant material; haven't decided on what yet. And I'm going to have to be careful about things shifting in there and getting up against that exhaust. After sailing, I'll want to check before turning on the heater.

I'd considered the hydronic and maybe that would be a better choice. Only time will tell. I decided on the air heat as it should better dry out the boat and wet clothes, and should use a bit less battery power, with just a single distribution fan. On the other hand, no hot water and more trouble installing ducting. I think if I'd chosen hydronic, I'd have installed it myself. I do plan to 'plug' an A/C system into the duct work, as a secondary run; the primary will be a 6" in the main cabin along with the return, which should keep the compressor happy. The heater duct work will just help distribute it throughout the boat; that's my theory at the moment.

There are many ways to do the above and I'm sure others will comment. My installation was done with lots of consultation with the distributor and the experience of the installer. Others may have different recommendations. I know that I will enjoy early spring/late fall sailing MUCH more since I won't freeze at night..!:)

Gary, someday when you have the time, it would be very helpful if you would photograph the full system, including furnace location, duct runs and outlets. Which Espar model did you install, by the way?

Thanks.

I'll take hi-res photographs of everything the next time I'm down, hopefully the end of next week. It was just completed this past Monday; spent a couple hours going over things with the marina owner. I had it on at night, but temp only in the upper 50's, so it hardly ran for 10 minutes.

I don't have the paperwork for the unit; I believe it's the Airtronic 4, but I will verify and pass along with pics and a description.

I'm in the process of putting one of these units in....would love to see some pics

cheers
Jason

This is the 'hell hole'.

The term is borrowed from the aviation industry, and isn't used in a disparaging way. It's just traditional. On an airplane, it is the area inside the back end (empennage) of the airplane, aft of the pressure bulkhead, where technicians have to climb in order to extract some black box, to or adjust something. Steve would know more about this than me, as he's undoubtedly spent way more time back there than I have.

The routing forward of heater ducting would be great from this location. However, I have NOT thought this all the way through. There could be important drawbacks to mounting a furnace in here, such as 1) fuel line routing that precludes the accumulation of air bubbles in the line, thus causing the heater to flame out; 2) heater exhaust routing might be tough to do without exposing the exhaust to damage in the lazarette; 3) challenge of mounting the furnace in the hell hole, and subsequent access for maintenance removal, etc. I think if I could find a decent exhaust routing that my other concerns could be mitigated.