Adding Webasto ST2000 to Hunter 376

[duck21]

Hi all!

I'm thinking about adding a Webasto ST2000 diesel heater to our new (to us) Hunter 376. The boat DOES currently have a Marine Air AC/Reverse Heat system with three vents through the cabin, but this unit is limited to operation only under shore-power. We sail on Lake Superior which can be quite chilly even through most of June, we're thinking the diesel heater could easily extend our sailing/anchoring season by making things a little more comfortable.

It looks like the heater would easily fit in the bottom of the aft cabin starboard locker with run to the diesel tank for fuel and a relatively straight-shot out the stern for the exhaust. The existing ducting "ends" with a vent in the aft cabin on top of the hanging locker right next to the aft-cabin /galley bulkhead. I'm thinking of adding a "T" to the flexible duct at that point and tapping the diesel heater into the existing duct work.

Does anyone have any experience with installing one of these units? Would adding a T to the existing system cause any issues? Or would I need to consider adding a baffle between the T and the diesel heater (I'm wondering if the AC/Marine Air unit would "push" cold air into/through the diesel heater instead up of up/through the aft-cabin vent).

I've attached a REALLY rough picture of what I'm thinking. The top image is the existing system (the 3 circles are the vents, the mid-square is the AC unit). The bottom image has the additional diesel unit/T in red.

If there are additional thoughts as to the installation/set up of diesel heaters I'm also open to any other feedback.

Thanks!

 

[jssailem]

a relatively straight-shot out the stern for the exhaust.

You'll need info from a person familiar with HVAC regarding the duct connections and proper circulation.

Regarding your "straight out the back" exhaust, I was advised by the Wallas folks when doing my install, to exhaust out the side, stern quarter. This reduces the exhaust drafting back into the boat over the transom.

 

[duck21]

Jumping into a thread I started a while ago--we ended up installing a Planar diesel heater which we used for our trip across lakes Michigan and Superior while transporting our boat home this past spring.

I wrote up an article for the 376 Owners Modifications board, for anyone who is interested. It may hold some value for owners of similar boats as well.

Hunter 376 Owner Modifications and Upgrades

Hunter 376 Owner Modifications and Upgrades

hunter.sailboatowners.com

I'm happy to answer any questions or entertain additional thoughts.

Doug

 

[Head Sail]

I've installed a similar diesel heater on my boat. It looks like your missing a drain at the lowest point of the exhaust. The goose neck will prevent sea water from entering the exhaust but you will still need to get rid of condensate that forms when the exhaust cools. There is a special pig tail type drain that can be purchased on e-bay.

Also, looks like lots of bends in that ducking. I'd orient the heater without the T. Why not tie into your diesel tank? You won't get much more than a few hours with that little tank.

 

[duck21]

Hi @Head Sail

These are all good points. I actually did purchase the pig tail for condensate, but space issues made it almost impossible to install. In researching the general consensus was that it wasn't as important for shorter exhaust runs (I.E less than 5 feet), which is the case here. I figured I'd try this configuration for a couple of seasons and, if condensate did become a problem, figure out how to add the pig tail.

I agree with the bends in the ducting. I'd love to have oriented the line straight in, but again, space and the desire to use existing ducting limited things. The louvered baffles do help. The up side--the aft cabin is probably the space that we want to heat the most (I.E. warming things up when we go to bed or first thing in the morning). With that being the shortest run, with the baffle open, that space gets down right toasty. I will say, the VBerth certainly does not heat up as well with this configuration, but it's also our least used space most of the time.

I debated hooking into the diesel tank. The run back to the tank was pretty limited, but wouldn't have been impossible. Many folks did note that these heaters can have issues with getting too much soot on the igniter from dirty fuel, however, requiring extra cleaning. I chose to use the stand alone tank and am actually burning kerosene, which burns much cleaner. Since we already have the AC with reverse cycle at the dock this isn't our primary heat source unless we're out on the water. I think we burned about 1.5 gallons of kerosene over the course of about 24 hours running, so we didn't find the smaller tank too limiting.

 

[Head Sail]

If it fits your needs and is safe, that's what matters. Drawing cold intake air from the main cabin would help with heat circulation too. Make sure you have a working CO detector.

 

[duck21]

Indeed. One detector in each cabin, and I added a fourth unit to the locker with the heater as an additional early-warning system.

 

[Head Sail]

That exhaust will get very hot. Enough to melt that plastic it's next to. I'd add some fiberglass insulation wrapping.
Where are you drawing combustion intake air from? It can be dangerous if it's coming from inside the cabin.