I've had one on my boat for several years (a Parker 27, basically the same hull) I fitted it under the cockpit sole on the inside of the longitudinal bulkhead below where the throttle Morse lever is (behind the battery box). The ducting runs straight along the underside of the cockpit sole, through the engine rear bulkhead and then bends down at the forward end of the engine compartment with a 90 degree outlet at the bottom of the engine/ saloon bulkhead. it's a bit of a squeeze with my 2GM 20 but do able especially if you only have a 1GM10. It's fed from it's own fuel tank which I had fabricated out of stainless steel and sits between the Morse lever and the gas locker and holds 5 litres, with its own deck filler above. Its roughly 3" x 4" x 15" tall with a site tube visible when the locker lid is lifted. I fitted the control panel above the hot air outlet on the saloon/engine bulkhead which was a mistake because it gets heated up before the main saloon really gets warm. I modified it with a remote temperature sensor at the foot of the hanging locker in the companionway forward, and also fixed a basic on/off switch in the fore cabin which only works when the unit is switched on at the control panel, but allows me to switch if off last thing at night and on again in the morning from the fore cabin. Don't forget to insulate the ducting. I used 2M of 85mm ducting if I recall. If you already have the Eberspacher or can afford their ridiculous prices, fine but otherwise look at the Russian/Chinese alternatives which are just copies of the Eberspacher but cost about a 5th or 6th of the price, or, if you want the authentic item, look at second hand units on Ebay, but factor in about £250 to possibly replace the ECU which tend to be the main failure point. Everything else is really quite easy to clean/rejuvenate or relatively cheap to replace. There used an Ebay seller based in Turkey who were the Turkish main dealers and their prices were very competitive for spares, but I can't find them now. That's how I put my system together with a defunct heater from Ebay (ca £100) then a new ECU and the rest as necessary (Trunking, exhaust etc.) Make sure you use the sealed cylindrical silencer, not the pressed 'pillow style' exhaust silencer which can leak carbon monoxide. Ensure you use tubular fibreglass cloth insulation over the entire length of the exhaust including silencer and vent it out the stern with a proprietary exhaust fitting. I think I used about two feet of 25mm stainless steel flexible exhaust hose. 6" from the bottom of the unit to bend aft, then the silencer and then the rest to the hull outlet. I also put a length of trunking from the main air inlet, to a vent on the starboard side near the foot of the under cockpit pilot berth but it's not really necessary, just encourages the airflow to flow down to the foot of the pilot berth. As a matter of interest, my space below my cockpit now holds my Eberspacher, Start battery (no room in the main battery box which now has two 105 A/hr deep cycle house batteries) and the pump and plumbing for my hydraulic keel lift system so it's getting pretty crowded now, especially as I am also considering putting a rigid water tank under there as well to replace the pillow tank and free up the lockers under the pilot berth.