Thank you. I wonder about the English influence. The unvoiced affricate seems to pop up right often in strange places, i.e. "chree" (supra), which I hadn't thought of before, but seems to be part of my ideolect. In both cases (chree and porchmuf), we see a slide back, from the dental to the alveolear. Maybe it's just the old lazy tongue, not coming all the way up to the dental position.
On another, not completely unrelated point, there is supposed to be a old Portsmouth dialect in which "mouse" "out" and "house" rhyme with "close" (as in "not far" a/o/t "not open". Anyone know anything about it? All I can remember is an article in one of the local papers, maybe fifteen years ago, about how the dialect was dying out. The only other place I've ever come across that particular treatment of the /ou/ diphthong was in Maine, which is right far North of here. Thanks again.