Moisture control under v-berth mattress

[hardee]

[Roamad]

Another vote for Hypervent. We lived aboard fulltime for 2 years on two different boats (30’ houseboat and a 35’ yacht) and used it both times to great success.

[thataway]

I might mention that "Thataway" C Dory 25, had the Nico Solar vents in the foreword hatch, and over the top of the cabin all of the way aft. There was a passive Nico vent over the area under the splash well, with extra louvered vents in the access hatches in the aft end of the cockit. That extra ventilation and air flow also helps.

[Boater Rob]

Sorry, yes we used the Dry-Den

[Peter & Judy]

We had the same problem with moisture under the mattress and in the cabin and berth overall. Being from bone dry Alberta we are probably hyper sensitive to the moisture when we are on the coast. We boat mostly off Vancouver Island, but have had our boat in the water from the Yukon to Lake Powell. We tend to attract bad weather when we are on the water, even sitting out a three day downpour on Lake Powell. I find the boat seems to get wetter when you are just sitting that cruising, probably because of the lack of ventilation that you get when the boat is moving. Solving the moisture under the mattress was just part of our moisture control strategy and sitting our storms in the Broughton's and Nootka Sound this summer proved that we were on the right track. We lined the entire berth area and the cabin ceiling with a marine headliner fabric. This product was glued on and it very complicated to install, but it does work well. We put this under the mattress as well and it has helped keep the mattress drier. But what I think is more important was to increase the heating and ventilation in the boat. We have a Wallace, which works ok to heat the cabin, but in an extended storm swinging on the hook, it was not enough. So I added a Wabatso diesel heater with a return air hose pulling heated air into the v-berth area and this works very well. The forced air moves a lot of air throughout the cabin. Also a solar powered vent was added in the cabin which helps to move more air out of the cabin. We also changed most of our bedding and sheets from cotton to polyester which does not hold the moisture as much. The result being that we didn't have to crawl into a damp feeling bed in the evening. Overall the system works well, but it is still good to lift the mattress up and open the hatches and windows when the sun comes out to dry things out. We split our horseshoe shaped mattress in two so that it is easier to lift and remove. Is our boats interior as dry as it is in Alberta? No, but it is more comfortable and a dripping ceiling is a thing of the past.

[C-Wolfe]

Thanks for all the reply.
I talked to someone at Mac's Upholstery in Seattle about their Hypervent and I'm waiting for a shipping quote from them. this product is very similar but seem a bit stiffer then the HYPERVENT AIRE-FLOW™ MOISTURE BARRIER, its also a bit more expensive ($12.50 vs $10/ft).I also find a rain shield for house siding that look extremely similar to the Dry-Den, I was able to order it at home depot with free shipping and easy return. It was same price as the smaller den-dry but it should be enough to cover at least 4 v-berth, so if it work good, I'll have some available for local sale .
Now for part two of moisture mitigation. Having little experience with it, it make me sleep better to always turn the wallas off for the night, Should I not be concern with this? How many of you keep it going all night?

[Peter & Judy]

[thataway]

I had to look this one up. I have used the Eco Fan, but this post from Scan Marine is in our archives: The bottom line is that you don't save much power, and there could be damage to the stove if you didn't run the stove with the lid closed--heating mode.

[Hunkydory]

I wouldn’t be concerned with it running at night, but we never have, as we sleep best with cold air & warm blankets. Besides, the biggest contributor to condensation forming on the inside of the boat along with breathing & heating water, during high humidity is the difference in temperature between the inside & outside of the boat. I’ve never been able to create enough air flow from inside to outside, if it’s around 40 degrees & raining, no matter how much the dry heat to stop the condensation. In fact the higher the heat, the more the condensation. In these conditions only enough insulation will prevent the condensation forming. We’ve experienced in SE Alaska during April & May these conditions many times. Yes, when the humidity is moderate & the temperature not to extreme, all the remedies mentioned so far in this thread will work fairly well. Over the years & cruises in SE Alaska, experiencing the many different conditions affecting the inside condensation in the boat, we’ve worked out what works best for us. Keeping the temperature inside the boat just high enough with sufficient clothing & ventilation to be comfortable. Adding more heat & then increasing the ventilation can turn into a catch 22. Heating during the night, when it’s difficult or impossible to ventilate sufficiently, will increase the condensation.

Also heating or cooking with unventilated propane like using a Buddy Heater or Coleman type propane stove will greatly increase condensation. During the times we lost use of the Wallas & turned to the Buddy Heater & coleman stove created our very worst condensation events.

Jay

[C-Wolfe]

All good info, thanks. In my last outing, it got a bit below freezing at night, a lot of condensation in the morning and it took several hours to clear (except for under the mattress which never did got dry) with the wallas only. I should probably look into improving the ventilation also but at those temperature, it might be something I have to leave with.
I do have a noisy blower on the stove , if I wiggle the lid a bit it quiet down but only for a couple few minutes, Wondering if I have a bumper of some sort missing? I have the 85D with the lid attach to counter separately from the stove unit.

[Peter & Judy]