Good morning Tailin strange,
Thank you for your inquiry. I had the opportunity to use the DFF3D a couple of weeks ago on a short sea trial. I do not possess all the answers for you but I will share my experience. The boat I was on was approximately 60ft with a bronze thru hull 165T-B54. The vessel was a typical sport fisher similar to a Viking. We went out to tune his sounder which needed a couple of tweaks to maximize the performance of the machine to the style of fishing the team did. We reached plane speed in shallow water 45ft for a little while. The bottom held solid and we certainly saw definition in the bottom structure. At trolling speeds around 8knts the bottom also showed good detail in the depth of water that we were working. I wish I had some photos for you but i don't have any to post. The product is still relatively new and the more units we get out there the more feedback we will have for you.
With bottom tracking, a lot of the performance of any fish finder is a direct result where and how the transducer was mounted. Some installations may perform at a higher level at faster speeds due to the water flow over the transducer. Some may have a great experience and some may have a poor experience at high and slow speed metering. Please keep in mind that does not necessarily mean the sounder is of poor quality or not working correctly. As a wise man once told me: "The transducer is the heart and soul of any fishfinder, without one of good quality and a good installation, the brain (processor) may not perform at a high level."
Please stay in touch and we should have more experience in the near future.
Best Regards,
C-Bass