Cabin Insulation

Having just got back from an overnight at the Pleasureboat Inn (and the really good fish and chips!), Puffin's cabin was saturated during the night and dripped all over our sleeping bags and the floor. It had been a warm day and a chilly evening followed, so adding our heat to the interior obviously caused the condensation. My book and all paper material aboard was also very damp. Has anyone managed to completely alleviate this problem and if so, what's the best lining material that is easy and cheap to apply? I noticed that some 'sea-hawkers' have used cork and others flock-type material. Do any of them really work? All replies gratefully received, as I have had an ultimatum from "her indoors" - no more over-nighting till it's fixed! Our door is the solid version, and was shut, but the two vents were fully out and seemed to make little difference.  

Hi Mike,

Greywing wrote

Having just got back from an overnight at the Pleasureboat Inn (and the really good fish and chips!),

I gather that they've had a complete refit of the kitchen recently and have taken on a new chef. Glad to hear that the food is now good.

Puffin's cabin was saturated during the night and dripped all over our sleeping bags and the floor. It had been a warm day and a chilly evening followed, so adding our heat to the interior obviously caused the condensation. My book and all paper material aboard was also very damp. Has anyone managed to completely alleviate this problem and if so, what's the best lining material that is easy and cheap to apply? I noticed that some 'sea-hawkers' have used cork and others flock-type material. Do any of them really work?

My father's SeaHawk, bought new from Reedcraft, had the flock finish in the cabin. Before he sold it, it had become stained with condensation runs, so even the official product had its limitations and I don't believe that Moore's offered it.

There are five pages with references to condensation on the site, but none explain my own experience too well.

It's five years since I've had Just 17 in the water and I do recall a couple of occasions when I needed to wipe condensation off the cabin ceiling and another when I seemed to suffer it under the quarter berths, but these were very rare indeed and looking back were probably under high atmospheric humidity conditions (of the kind we've just had).

Virtually all my sailing was done on weekend cruises so I slept aboard two and sometimes three nights most times I used the boat. Just 17 has no special anti-condensation measures. While I did spend a few nights on my mooring at the PB, most of the time I was solo and would overnight on a mud weight mid-broad (Barton and South Walsham being favourite destinations).

A typical evening would include boiling rice and heating a defrosted curry brought from home and, probably, a kettle for a mug of tea. Only very rarely would I be aware of any condensation come morning and I could always lay the blame a combination of lack of ventilation and high humidity.

As ventilation is the key to tackling condensation. I would tend to cook with the fore hatch propped up by an inch or so at its leading edge (unless it was really blowing a gale when enough draught would enter through the unsealed fore hatch, even when closed.). When cooking I would also always have the upper half of the cabin door in the cockpit or similarly propped.

I always slept with the upper half of the door propped open as well. In high summer, if I was aware of high humidity conditions, I would also tend to sleep with the fore hatch propped. In exceptionally still nights in high summer I have even been known to sleep with the upper part of the door left in the cockpit.

Maybe, being solo makes the difference. I have only spent a couple of nights aboard with Diana - and one of those was moored outside the PB in either October or November but I don't recall us suffering any excess condensation then.

Being on a mud weight means the boat lies head to wind and I have convinced myself that this helps enormously in reducing condensation. Any steam from cooking or simply from my breath overnight gets taken out of the cabin. It may also help that you sleep behind a bulkhead in a two berth boat and so you get the maximum protection from any draughts entering the cabin from the bows that helps make it seem warmer.

I do all this throughout the year, not just for summer cruising. I have been known to overnight from mid March to Late October and there have been a few occasions when I've awoken to find frost. It's warm enough in a SeaHawk cabin when cooking, and outside the "summer" season I retire to a good quality sleeping bag early, to keep warm.

I'm not convinced that there is a product available that is sufficiently thermally efficient to be useful in a SeaHawk. The most efficient foams need lining themselves as they're just not robust enough to resist knocks, scuffs and scratches. And a lining for the insulation is not practical in a boat as small as a SeaHawk. And, of course, then there'd be double glazing to sort out for the windows.

It comes down to this:

The two things most associated with generating water vapour are cooking and people breathing.

As insulation is impractical, the single most important thing to do is ensure a flow of air through the boat - and make sure the bigger vent is on the downwind side so it can escape easily taking any excess water vapour with it.

A single vent, even a large one, will not allow the necessary air flow. Just 17 has a large vent with no closure mechanism in the top of the cabin door, but I still didn't consider that enough to encourage a good flow of air through the cabin.

Does any of this tie in with other's experience?