Webasto heater left on in winter

[Normf943]

My c28 has the webasto diesel heater. Appreciate anyone’s thoughts on leaving the heater on at a low setting for winterizing purposes during cold weather in the Pacific Northwest.

 

[SJI Sailor]

I personally would not leave the heater on while I was away for any appreciable time, except as a last resort backup. It is too risky IMO.

In Seattle on our former C30 we used an electric bilge heater (Twin Hornet) plus two Caframo cabin heaters, one in the stateroom and one in the galley. To get more air circulation I propped open the various cabinet doors including head, and also drained water system as best I could (run pump until it's empty and leave faucets open). Shutoff valves for the transom shower and drain those lines and leave it open. RV fluid in the toilet.

With that plan, across 4 years, temperature recorders in the cabin and engine room never dropped below 40. The main issue is to make sure you have reliable shore power and get notified if power goes out (and that's when I might consider the Webasto). I use an iSocket device for that but there are other options especially if you have WiFi at the dock.

There is one issue I've had *outside* the hull: a couple of years ago we were docked in Friday Harbor and it was below 20 degrees straight for several days. Choppy waters led to a build up of ice on the hull ... and the bilge pump died, apparently from pumping against that external ice. Those due periodically anyway, so it's not a huge deal apart from the risk if it were unattended for a long time.

 

[Normf943]

Thanks Sji. Your response was very helpful.

 

[glider4]

Would not recommend using the Webasco heater when you are not on the boat.
We use the Twin Hornet 66 in the bilge of our C-28
In the cabin are two Caframo dehumidifier/fans with a True North heater that turns on automatically when it’s below 38 degrees.
All doors open inside the cabin to keep temps and humidity as constant as possible in all spaces. Refrigerator emptied, defrosted and turned off with door propped open.
We are on the trailer in the winter with the boat plugged into house “shore power” so we know if there’s a power outage. Also we do a full winterization of everything with RV antifreeze.

 

[Submariner]

My c28 has the webasto diesel heater. Appreciate anyone’s thoughts on leaving the heater on at a low setting for winterizing purposes during cold weather in the Pacific Northwest.

Webasto recommends that when you run the heater, you run it full blast, full heat. If it gets too hot inside, open a window they say. By running the heater too cold will cause it to build up carbon and other deposits in the burner insert and will require additional maintenance.

I wouldn't recommend using it for the off-season storage because you'd want to keep the boat around 40 degrees and not 70 degrees. The boat itself is not very insulated so it cools off quick. To run it for off-season heating would just be asking for maintenance issues.

When we're on the boat we don't even run it over night. We turn it on hot, get the cabin warm. Turn it off and go to bed. Wake up in the morning, turn it back on to take the chill off. So when we run it, we run it hot, or we leave it turned off.

For winterizing, we run a Caframo electric heater set to 40 degrees inside the cabin and a dehumidifier.

Winterizing
https://www.letsgochannelsurfing.com/boat-maintenance/winterizing

 

[Normf943]

Thanks Martin and Latina. Your response was helpful. By the way I have logged on to and bookmarked your very informative website. A wealth of information that I found very helpful. Thank you very much I appreciate the amount of work that you have put into tug nuts and your website.

 

[Normf943]

Correction. Lazina not Latina. Sorry.

 

[Submariner]

Thanks Martin and LaZina. Your response was helpful. By the way I have logged on to and bookmarked your very informative website. A wealth of information that I found very helpful. Thank you very much I appreciate the amount of work that you have put into tug nuts and your website.

Thank you!

I've spent a ton of time this past week on the website. Lots of changes. I completely redid and updated the Boat Maintenance section and the Information section. The Upgrade section was re-done a few weeks ago.

With switching the web site from static pages to dynamic pages for the Information, Maintenance and Upgrades section, it's now a lot easier for me to add content to the site. So look for more to be added as I go through the 115,000+ pictures I have on my phone. Also, winter project season is upon us, so I'll be adding additional routine maintenance items to the site as I work on Channel Surfing. 🙂