After lots of research I finally got a fish finder for my Ultra.

A bit of background. OK Ultra 4.7 has a scupper hole, which, while marketed with the focus on Humminbird's ( OK even sells specific installation kit for Ultra+Humminbird), is also supposed to accommodate wide range of transducers, including (and demonstrated by others) Lowrance's transducers

But here's where fun begins:
- Newer DI transducers from Humminbird require different installation adapter, as confirmed twice by their reps - which is for through-the-hull installation.
- There were anecdotal suggestions that newer transducers from both Lowrance and Huminbird are larger then a-bit-older ones (some of which already were known to stick out of scupper hole)

Since I wanted HD/DI transducer I could not take advantage of OK+Humminbird's scupper mount, hence this was not a advantage of going with Humminbird, and chose Lowrance Elite 5 CHIRP  000-11655-001

So, with this being my first fishfinder and quite a discouraging results from research I was ready for through-the-hull installation. I did not want to mess up with my brand new Ultra, especially drilling holes and I'd rather had somebody else do it.

Lots of great information from the forum, but here's when awesomeness of this forum really kicks in. Immediately after I asked for help two people offered their help - and first one was Bushy, who offered his help of a simple "'bro' stuff"!

So, last Sunday after great day on the water in SC I stopped by Bushy's place, had a chance to look at "Sanctum Sanctorum" and see Bushy in action.

Couple of notable things:
- despite my concerns per Bushy's recommendation I bought Lowrance's scupper mount  000-10606-001. And with thos mount transducer did fit nicely into the scupper hole and does not stick out at all! (I still would prefer that mount to be more rigid, but there are no readily available options)
- I read people had a problem routing Lowrance's power cable to the Ultra's center hatch; some I believe had disassembled power cord to route it through. Well, Bushy ingeniously disassembled hatch's cover and it was a snap after that.
- everything can be done with a wire and a tape, and that's how Bushy did it! (well, + couple of dozens of other tools, neatly organized in his "Sanctum Sanctorum".

Fantastic quality time and professionally installed fish finder. Thanks a lot, Bushy!

P.S. Unfortunately, I screwed last picture, two times

... My wife is so stoked with the chile vodka...

PS we need to but the retaining ring back on the pivot tube.....I have it, neatly stowed in the sanctorum.  Just be careful opening/closing/pivoting.  When it's closed and dogged down, it's just fine.

Too much hassle, I think it's just going to be a good reason for me to go south, on 15th or 16th. Hopefully it will survive one fishing day tomorrow w/o retaining ring. Thanks for reminder!