Chessyman,
A few things that you might consider:
1. How easy would it be to switch from a transom transducer over to a thru-hull transducer..?
2. How to you intend to utilize a new transducer for fishing and/or navigation..?
3. How fast is your vessel, what trolling speeds do you intend to use..?
The CA50/200-12M is a 1kW thru-hull transducer and it doesn't come with a fairing block. It does have a 28 degree beam width on the low frequency side, and a 8.5 degree beam width on high frequency side.
The 526TID-HDD is also a 1kW thru-hull transducer that comes with a high speed fairing block. It uses a 20 degree beam width on low frequency, and 8 degree beam width on high frequency.
- Deep Blue :think