Wabasto Exhaust Thru Hull

[Lepke]

Has anybody installed a Wabasto with the exhaust going thru the hull, and what did you use for a thru hull. What heat protection for the hull does the thru hull have? I have a wood hull.

I bought a DBW 300 on eBay and plan on replacing an ancient boiler that uses a dry stack. The Wabasto would give me better installation options if I could exhaust thru the hull and free the space the existing boiler uses.

 

[Nomad Willy]

I did Lepke,
Did that on my Albin25.
I just used the hardware available at Sure Marine. Was a straight fwd installation.
Try to hang your fenders a foot or two away from the exhaust. The exhaust discharge was about amidships.
If your boat pulls to stbd may be better on the port side. Mine, however was on the stbd side but as I recall the Albin pulled to port. While running the boat in transient slips it may be better on the outboard side.

 

[Ken E.]

As Eric said, specifically-designed exhaust through hulls are available. I use one with my Espar. Mine is next to the dock and I always check to see if anything is in the way or getting hot....dock, fenders, lines. It's never been a problem.

 

[Lepke]

Thanks, I'll check out Sure Marine. In cold weather the unit is marginal for my boat and will run for long times if I'm not also using other heat sources. I don't need a wood hull fire. It will probably exit above the usual dock. Thanks again.

 

[syjos]

Sure Marine is a Webasto distributor and very qualified. The've developed modifications for Webasto furnaces and boilers that ease installation and troubleshooting.

I was trained by Sure Marine and sold and installed Webasto before retirement.

 

[DDW]

I just installed the Webasto thru hull on my fiberglass hull (though not for a Webasto heater). Straight forward, other than for one detail: They supply a squishy thick gasket that is intended to both seal and insulate. I thought it needed some sealant, and used hi temp silicone. The problem is, when you tighten the fasteners the gasket wants to squish out from under the flange, lubricated by the wet sealant. So assemble it and snug it up, then wait for the silicone to set before tightening to final tension.

 

[Nomad Willy]

DDW,
Maybe one dosn’t need sillycone?

 

[BruceK]

I`m considering one of these, or another somewhat different model, both available on ebay,at modest cost: https://www.ebay.com.au/itm/AU-All-...3dc1cb9e12421983014df0316587fd&frcectupt=true
My main concern is setting up the exhaust. I`m assuming the exhaust gas will be hot. I thought about routing it via either an engine or genset exhaust hose but not sure about cutting into one,or putting dry hot exhaust gas into one.

So very interested in this thread. And any comment which might help. Though our climate rates as "temperate", winter nights get cold(by our standards)and a heater would be good to have.

 

[hollywood8118]

I`m considering one of these, or another somewhat different model, both available on ebay,at modest cost: https://www.ebay.com.au/itm/AU-All-...3dc1cb9e12421983014df0316587fd&frcectupt=true
My main concern is setting up the exhaust. I`m assuming the exhaust gas will be hot. I thought about routing it via either an engine or genset exhaust hose but not sure about cutting into one,or putting dry hot exhaust gas into one.

So very interested in this thread. And any comment which might help. Though our climate rates as "temperate", winter nights get cold(by our standards)and a heater would be good to have.

the exhaust is typically ran in a stainless steel flex pipe and then wrapped with a heat tape.. it gets VERY hot.
HOLLYWOOD

 

[BruceK]

the exhaust is typically ran in a stainless steel flex pipe and then wrapped with a heat tape.. it gets VERY hot.
HOLLYWOOD

That "Very hot" exhaust pipe has to pass through the hull to vent outside. How is that resolved without burning fiberglass on the way through?
At least one model of heater has a mini size car type muffler at the end of the exhaust piping. that`s going to look odd outside, and need supporting,maybe dispense with it unless the unit becomes noisy.

 

[syjos]

The Webasto exhaust thru hull has air gaps to dissapate heat away from the hull.

 

[dhays]

I had a Webasto AirTop installed on my last sailboat. It worked really well, but the burner is somewhat noisy. The exhaust was vented out the stern through a SS fitting supplied by Sure Marine. I paid a friend to do the installation.

The exhaust is very hot, so you want to place it won’t be close to anything external to the boat. I always tried to make sure that I had about a foot clearance from the exhaust exit.

Sure Marine can tell you can use for a wood boat.

 

[DDW]

DDW,
Maybe one dosn’t need sillycone?

Perhaps not - but there are only three small fasteners allowed for and little else to hold the gasket in place. In my installation the flange does not get hot enough to require silicone, but in an air system it might. This is one of the very few situations where silicone sealant might be appropriate on a boat.

 

[Nomad Willy]

DDW,
Silicone as in high temp red?

Lepke,
Don’t worry about all this “hot” talk.
Get w Sure Marine and use their hardware and instructions.
Re the noise Iv’e never ever had a problem w it. However if you’re a very light sleeper ......
For lack of noise it’s ideal to put the furnace at the opposite end of the boat. Ours is aft of the engine compartment on the Willard. Just ahead of the Laz bulkhead. Exhaust through stern. I think the max exhaust hose length is 15’ .. for the Airtop 2000 (smallest) and we’re at 15’.
FYI the bigger the furnace the more often it will need to start up. So the high (relatively) current draw then will mean it will drain your battery more-so. Ideally for efficiency the furnace will run all the time only needing to start once. But when it gets colder it will be colder in the boat. When the temp gets to about 28 degrees outside our Waby (Wabasto) will run almost all the time.

On a long run when I step out on the aft cockpit I’m often surprised to hear that I’ve got the heater on. I run the Waby underway as our small buss heater makes too much fan noise.

Another FYI is that much cleaner burning can be had burning kerosene. I replumed for it and been fine for some time. Gotta carry plastic jugs of kero as the day tank is small .. 2.5 gal.

 

[DDW]

DDW,
Silicone as in high temp red?

Yes. That is Webasto's suggestion. (Can be had in grey as well, if you are matching colors )

 

[FF]

"Don’t worry about all this “hot” talk."

But realize a fire on a wood boat is easy to put out.

GRP burns 500% better than wood , and is much harder to put out.

The thru the hull exhaust on a GRP boat must be done right!!!

 

[Vadim]

https://www.amazon.com/gp/product/B076PNPM6W/ref=ox_sc_saved_title_1?smid=A3NC9MITBLZONZ&psc=1
But before you order it check your exhaust pipe diameter. My is 24mm. and it fits perfect. It is also very important where are you going to install the heater. I've seeing some people add a baseboard water heater (without water) plumbed to the exhaust and then out to consume all the heat from the exhaust as well. Funny part it works pretty well.

 

[Roamer Blue]

Hold the phone... A DBW 300???


That's a 104 000 BTU unit, with a big exhaust pipe.


That install has to be carefully thought about, and the stuff in the path of the exhaust is going to feel it.


I had one in the big camper. Tons of heat, quick, but short cycles when only a small amount of heat is required.


A bird in hand and all that... be careful!

 

[BruceK]

Found this:https://www.ebay.com.au/itm/Stainle...m21302cf021:g:160AAOSwPAxZ5eoL&frcectupt=true
That`s AUD,so way less in USD. Seller in Russia(!) but it comes from Asia.
But, would the hull the fitting passes through get cooked, or worse?

 

[TDunn]

I used the thru hull exhaust fitting that was supplied with my Webasto Airtop 2000. I have a wooden hull and have had zero problems in the 5 years since I did the install. You can see the exhaust fitting in my avatar picture. It is the black dot about 15" fwd of the transom just below the upper rub strake.

 

[Lepke]

I have a large chain locker and I'm thinking of putting it there. I'm gonna look at the thru hull but concerned about the heat, and my wood is 75 years dry. I may build a wet exhaust loop with a pump that comes on with the heater. My hydronic insulated lines run the length of the boat, so I could tie it in easy. Then the noise is far away and still one compartment from the crew quarters. And that's 2 compartments from my stateroom.
That opens a space in the engine room about 2.5'x2.5'x6'. I need a new space for my water heater. And that would put it almost directly below the diesel stove that has a coil for water heating. With the boiler gone I could replumb and insulate the last of the main hydronic lines.
Boiler is from 1973 (I think) and the plumbing and wiring going to it are kinda mickey mouse. Boiler is probably past its reasonable life. When I bought the boat I found the boiler circulation pump was installed backwards. I wondered why it took so long to heat a cold boat w/ 120,000 BTUs.

 

[ksanders]

The very safest exhaust ofr a diesel heater is a tube within a tube design that Wallas uses.

The exhaust tube is the inner tube and the combustion air intake in the outer tube.

This results in the exhaust pipe being just warm to the touch, Much safer than the single tube designs.