Wanted to use a Helix 7 DI GPS on the front of my boat. Asked the rep at the 800 # if I could swap the transom transducer for a TM transducer, he said no problem, just mail it in new & unopened. When I got the unit, I called to confirm the address, and the lady said there would be a $60 "upcharge". I told her what I had been told, and that they preform the exact same function. She said the TM one has more plastic in it. Give me a break, $60 worth of plastic??? I can get the adapter, I know, but I hear they break very easily.

Well....you want the trolling motor mount for sure. I have the exact same thing on my trolling motor. $60 is absurd. I use the regular transducer that came with the Helix 7 DI and bought the trolling motor adapter for $29. It is basically a different, non adjustable, mount and two stainless band clamps to accommodate large or small trolling motor housings. $60 is a rip off. Especially if you are exchanging. Should be an even exchange.

Sounds to me like she was confused with trading a non-hi def transducer for a hi-def.
I have exchanged a few times and was not charged.

Thanks for the input. By the way, if you get the Helix 7 SI GPS for your console, there is another surprise. If you want a reading @ high speed (35+ MPH), you have to get a second transducer, a Y cable, and a switch. I thought high speed was defined as 65+ MPH, but not so.

The need for a second transducer for running/reading on pad is nothing new.

Neither is needing a Y cable when you do it. I have no idea why he thinks he needs a switch though.

I'd do yourself a favor and get a transducer shield and saver to mount that transom transducer onto your trolling motor, they're solid, you won't lose a transducer from clipping a rock or stump, guaranteed. They might cost 100 bucks or so, but they're well worth it.

http://www.transducershieldandsaver.com/

Good luck!

Some misinformation is this thread.

There are two trolling motor PUCK DI transducers. Both of them have extra internal shielding to help with possible RFI from the trolling motor. They don't need a mount, they come with stainless steel hose clamps. They cost more to construct.

The transom mount transducer which can be used for shoot-thru also does not have that shielding.

Since the Helix 5 and 7 DI models just have 200/455 kHz capability, the XTM 9 DI 25 T is the PROPER transducer for those models for transducer mounting.

The DI models with 83/200 kHz capability can use that transducer or the XTM 9 WIDE DI 20 T to have more coverage.

Bottom line is use the correct parts for the application.

Next is the transom mounting of a transducer for high speed depth readings. The transducers can be installed to give high speed depth readings. That is why they are shaped/designed like they are and have a transom mount bracket. As with any installation, getting the correct location and attitude to get that performance is difficult at the highest speeds and typically most don't want to expose that expensive Side Imaging transducer to possible impact damage.
Another thing with a thin fiberglass high performance pad hull, it is best to use a shoot-thru transducer for the best sonar performance at speed.

When using two transducers you have two choices. One is the AS SIDB Y cable that splits off the 83/200 kHz crystal from the SI transducer and connects the shoot-thru in its place. It is electrical connections so no unit settings are changed.
The other is a transducer switch TS3 and allows selecting which of the two transducers the display uses. Some use that because they think they get better 2D performance with an exterior transducer than a shoot-thru. They just use the shoot-thru at speed. Additionally some use a shoot-thru with remote temp sensor and put that sensor in the livewell to monitor the water temp when navigating between fishing locations or to the ramp.

It's all about installing the equipment rather than just mounting it. You customize your installation for your hull.

Thanks, Wayne for your input. You sound like a very sharp guy. My main issue was that I called before I purchased the unit & the rep told me I could swap the transducers. If he didn't know what he was talking about, I think they should train him, not penalize the customer. In any event, I just wanted people on the forum to realize there may be additional gear (and expense)required on these purchases.