I've got an ex RNLI D-Class IB1 which I'm fitting a Raymarine Element 9 plotter into.
I also have laying around a brand new CPT-100 Transom mount transducer, I am curious if this will be any use on the D-Class or if the water flow past the transom and the Mariner 50 is likely to be too turbulent to work.
Neat job. I didn't notice this post last year but would have commented for some reason it just seems logical between the OB and starboard tube... and that location always seem to work well on a SIB... although I've no experience with that level of HP.
I've only had the boat out 'once' since finishing the rebuild. I took her out on Poole harbour a couple of times over the course of a weekend, I didn't really use the sounder unfortunately.
The boat is now in pieces again however, and I'm looking to replace the bracket with a modified version over the next week or so.
Looking at the bracket you made, IMO I thought the transducer was maybe a little high and would benefit from being a tad lower in the water so it was inline with or slightly lower than the AV plate.
Mine is on a sib, so may be completely different, but I found inline with the AV plate gave the best consistant readings without causing drag.
If you are 3d printing a new one and make it a bit deeper in the water see if you can incorporate a flip up part so that when you come into beech you can flip it up to avoid damage as that looks to be quite a bit transducer
It is ABS, with A4 stainless nuts embedded into the print for the two lower holes (which are slotted on the transducer), and a floating nut in a slot for the upper mount (which you'd typically drill after you've adjusted the transducer to final position).
