This is a question for those of you who are accomplished cranners: do you tongue any of the cuts to achieve greater clarity and if so, which one(s)?
Thanks lots,
Jon
Cranning, as I’m sure you well know, began as a piping ornament, and while it can be done fairly well on a whistle, it will never have the same sort of snap or tone you’ll get from a chanter. That being said, most crans are played MUCH too fast for articulate, clean tounging. I’d just work on breath control and snappy fingering - much the same as with the pipes.
Try playing slowly and work on the finger placement and tone. It will come with time and practice.
Play cranns legato.
On the other hand, wonder if it’s really worth using them at all, I have by and large moved away from using any piping ornamentation on the whistle in favour of the things a whistleplayer would do.
I must say I really enjoy playing crans on the whistle and although the sound isn’t as good when compared with the pipes, its a nice break from doing rolls and cuts.
I only use crans on one or two tunes when playing whistle. Like Brian noted, they’re usually too fast to put a whole lot of tongueing into. But do use a little tongue when accenting the beginning of the cran.
The main tunes I cran on are “The New Mown Meadow” and “Chorus Reel” and the emphasis is on the downbeat and the cran notes are pretty legato because they follow the momentum of that downbeat.
I am trying to sound like the pipes and specifically, Jerry OSullivan, who performed New Mown Meadow here in Oakland a few years back. I think they sound good on the whistle (at least from behind, nyuk).. There is one other slip jig which is named something like Paddy Go Aisy (but there are about five tunes with a name similar to that; this one is out of ONeills in the Slips section).
It starts on a low cran for the A section. The B section has a cran on the middle D. And, very cooly, the C section starts on a middle D but drops down to cran on the low D. Its a neat effect, when I am in practice and can make it sound effortless.
Crans are cool but best used sparingly, I reckon.
At least if said whistleplayer were not trying to imitate a piper. 
But I’m with you… I tried throwing crans in all over the place a couple of years ago, but these days I’ve mostly given up on it. I never hear them played by the players I’d like to sound like.
I wouldn’t mind sounding like Willie Clancy.
I use a lot of D-crans and I do tongue the initial D.
When I started on whistle I did lots of crans, probably because I’d always liked the sound of them on pipes and so I’d developed cran-like ornaments on other instruments like sax and guitar—not for Irish music as such. The more I play Irish music on whistle, the less I use crans. I’m not entirely sure why.
Well, I am a piper most of the time, I did say by and large, the odd one may fall in here and there but the whistle will never achieve the same strength a chanter will have rhythmically when playing a cran in reel figures like AD ~D2 AD ~D2 it’s much more effective on the whistle to play AD{A}FD or AD 3(FED. That said, I am cutting down on the cranns on the pipes too so maybe it’s just one of these phases. They have their uses, sparingly, in moderation, used with taste and all that.
I like to use crans to ornament high D’s rather than low on the whistle, since no one can ever hear my low D crans in a session anyway. (I have a quiet whistle).
I think they sound cool on the high D, especially when I am playing with pipers and they can’t do it, ha ha. 
Justine
I like the D cran, but i rarely use it in true Irish music. Go figure.
On the other hand, the fake cran on E is often a good alternative to a roll. Good to add variety.
Must have been difficult to get the subject line past the censors. Anyway, the only cran I’m conscious of doing is the d cran in the second measure of lines 1 and 2 of The Rolling Waves (aka The Lonesome Jig). I don’t do any tongueing therein.
Philo