Condensation in narrowboats

When we were last on Jubilee, a couple of weeks ago, we had pointed out to us a condensation problem. At least, I assume it's condensation. The outside temperature was low; the stove was on; and there were four of us breathing and cooking inside. The windows were running with condensation, which wasn't a problem as I'd recently cleared the "limber holes" to allow the water to drain to the outside.

(I discovered the name of these holes only when reading the December issue of Canal Boat magazine.)

The problem? Water was dripping from under the gunwale onto the pillows of the convertible dinette bed.

Looking under the gunwale I can see the 1/2" copper gas pipe, and not much in the way of spray foam insulation. I don't know if it was cut away in order to route the gas pipe through, or if this area never got the spray foam treatment. I'm fairly sure, though, that this is the reason for the damp pillows (and the damp seat cushion when in its normal use as the dinette).

I think the solution will be to spray more foam up there. Is there any regulation about not spray foaming a gas pipe? Does anyone know?

Incidentally, an article about condensation in the December Canal Boat mag is followed immediately by Tony Brookes's advice column. The two articles seem to differ in their recommendations regarding ventilation. The first (author anonymous) article warns against "excessive" ventilation, as "cold and persistently damp winter conditions can bring in more moisture than it vents out" (p86). Tony Brookes, on the other hand, advises keeping "as many window hoppers open as you can to help ventilation throughout the boat. This will go a long way to reduce condensation problems."

So what is one to do?